Design Follows Availability: Design of Affordable Dwelling Units based on reclaimed materials in San Antonio

ExecutiveSummary

Introduction

Wood waste in the United States is a significant issue from a waste management perspective. According to the U.S. Environmental Protection Agency (EPA), wood debris made up about 18% of total construction and demolition debris generated in the United States in 2018 (EPA, 2019). This high level of wood waste is due in part to the growing construction industry and the increased rate of demolition and renovation of existing buildings. Wood waste is a challenging material to manage, as it can take a long time to decompose in a landfill, and burning it can contribute to air pollution. However, there are many efforts underway to reduce the amount of wood waste that ends up in landfills. For example, some companies and communities have established recycling programs that repurpose wood waste into fuel for boilers, animal bedding, and other products. In addition, the use of salvaged and reclaimed wood has been growing in popularity in recent years, as consumers and builders look for more sustainable building materials. This trend has helped to reduce the amount of new wood that needs to be harvested and has provided an outlet for the reuse of existing wood products. The use of salvaged and reclaimed wood has also been shown to have a number of environmental benefits, including reducing greenhouse gas emissions and conserving forests. Despite these efforts, wood waste remains a significant problem in the United States, and much more needs to be done to reduce the amount of wood waste that ends up in landfills. This will require continued investment in recycling and repurposing programs and increased public awareness and education about the importance of reducing wood waste.

There have been growing efforts to recycle and reuse deconstruction wood in recent years. These efforts are driven by a desire to reduce waste and conserve natural resources, as well as to create more sustainable building practices.

One of the main ways that deconstruction wood is being recycled is through the creation of wood products, such as wood chips, sawdust, and mulch, which can be used as fuel or as landscaping materials (Figure 3). This type of recycling

diverts the wood from landfills and provides an alternative source of fuel for

boilers and other heating systems. Another way that deconstruction wood is being reused is through the use of salvaged and reclaimed wood in construction and building projects. This trend has grown in popularity as more consumers and builders seek out sustainable building materials. Reclaimed wood has the advantage of being a unique and characterful building material, and it also provides a way to reduce the demand for new wood products, which can help conserve forests.

The process of salvaging and reclaiming wood can also create jobs and support local economies, as it requires specialized skills and knowledge to process and prepare the wood for reuse. In addition, the use of reclaimed wood has been shown to have a

positive impact on the environment, as it helps to reduce greenhouse gas

emissions and conserve energy that would otherwise be used to produce new wood

products. Overall, the growing efforts to recycle and reuse deconstruction wood are a positive trend, and they demonstrate that it is possible to create a more sustainable future through creative and innovative solutions to waste management and resource

conservation. Reusing deconstruction wood from historic buildings has a number of benefits from a historic preservation standpoint. These benefits include:

1. Conservation of historic resources: Reusing wood from historic buildings helps to conserve historic resources, as it allows the original materials to be used again in new projects. This can help to maintain the character and authenticity of historic structures and to preserve the cultural and architectural heritage of communities.

2. Cost savings: Reusing existing materials can be more cost-effective than using new materials, as it eliminates the need to purchase and transport new materials. This can help to reduce the overall cost of a project, while still providing high-quality building materials.

3. Sustainability: Reusing wood from historic buildings is an environmentally sustainable practice, as it reduces the demandf or new materials and conserves resources. In addition, it helps to reduce the amount of waste that goes to landfills and reduces the carbon footprint of aproject.

4. Unique character: Wood from historic buildingsoften has a unique character and patina that is not found in new materials.This can add a distinctive quality to new projects and help to create aconnection to the past.

5. Community value: Reusing materials fromhistoric buildings can have a positive impact on the community, as it helps topreserve local history and cultural heritage, and supports the local economy bycreating jobs and promoting economic development.

Overall, the benefits of reusing deconstruction wood from historic buildings are substantial and multi-faceted. By repurposing these materials, communities can conserve historic resources, reduce waste, conserve energy, and promote sustainability, all while supporting local economies and preserving cultural heritage.

Reclaimed and salvaged lumber is becoming an increasingly popular material for building and construction projects, due to its potential for reducing waste and conserving resources. In recent years, several studies have been conducted to evaluate the quality and characteristics of recycled wood, including reclaimed and salvaged lumber. These studies have shown that recycled wood can have comparable strength, stiffness, and durability to newly harvested wood, and that it is a suitable material for use in building construction. One study, "Evaluation of the Physical Properties and Durability of Recycled and Reclaimed Lumber" (2007), compared the physical properties of recycled and reclaimed lumber to those of newly harvested lumber. The results showed that recycled and reclaimed lumber had similar physical properties to newly harvested lumber, and that their strength and stiffness were comparable to that of new wood. Another study, "The Durability of Reclaimed Lumber for Outdoor Applications" (2010), evaluated the durability of reclaimed lumber for outdoor applications, such as decks and siding. The results showed that reclaimed lumber had good durability and resistance to decay and insect damage and that it was a suitable material for outdoor applications.

The use of recycled wood in construction projects has a number of environmental benefits. By reducing the demand for newly harvested wood, recycled wood helps to conserve resources and reduce the carbon footprint of a project. Additionally,

repurposing wood from demolished buildings helps to reduce the amount of waste

that goes to landfills, further reducing the impact on the environment.

Despite its potential benefits, it is important to note that the quality of reclaimed and salvaged lumber can vary, depending on the type of wood and the method of preparation. It is always recommended to have the wood evaluated by a professional before using it in construction, to ensure that it meets the necessary standards and

requirements.

Accessory dwelling units

Accessory dwelling units refer to the extra residential units that are incorporated into a pre-existing single-family or multifamily property. These supplementary living spaces can be built attached or next to an already established structure, such as a house or apartment complex. Many cities are adopting policies and programs to make the construction of ADUs more straightforward and more cost-effective as part of a comprehensive, affordable housing strategy. This topic is outlined as a local

priority in the Strategic Housing Implementation Plan (Council, 2021). For an average-sized home, the lumber salvaged from one deconstruction project could potentially be sufficient to construct the structure of an ADU at a minimum. This project helps inform how San Antonio can develop a Salvage-to-ADU program that utilizes reclaimed building materials to build new affordable housing units. Such a program would simultaneously advance multiple goals: create affordable housing, promote the circular construction economy, and raise awareness of the importance of combating these crises. This would be an opportunity to educate homeowners on how to finance, build, and manage an ADU and an opportunity for education on building with reclaimed materials.

According to the sources, the reuse of timber in construction is currently not widely practiced. This lack of widespread adoption can be attributed to several barriers, including a lack of demand for salvaged materials, absence of standardized design guidelines, and restrictive building regulations. The ease with which a building can be deconstructed for potential reuse largely depends on its method of construction.

In order to ensure sustainability in timber construction projects, it is imperative that considerations are made regarding the deconstruction, reuse, and recycling processes right from the planning stage itself. This approach would enable long-term and material-efficient use of high-quality wood.

To reduce costs associated with constructing stilted buildings or structures while simultaneously promoting innovation in the industry and minimizing environmental impact through efficient resource utilization has been suggested by architects who advocate using alternative reusable and recyclable materials. A study carried out by Osmani and Villoria-Saez further supports this argument as it reveals that employing reclaimed timber could result in an impressive reduction of up to 80% in environmental impact. Reclaimed timbers are often obtained from demolished old structures or buildings known for their strength.

It should also be noted that wood products have the potential for various end-of-life scenarios

This project will address the latter option while informing the following steps on developing a pattern book or design guidelines for ADU construction. To further incentivize property owners, the City could streamline the permit process for constructing ADUs with salvaged materials, which is a critical policy goal of OHP. This project also helps further identify functional components of the Material Innovation Center (MIC) through evidence-based research and development. The project aims to gather information and knowledge on how the Material Innovation Center can fulfill several important roles. These include sourcing and distributing materials for various affordable housing programs in the city, such as the Shotgun Pilot Project, REHABARAMA, and Owner-Occupied Rehab Program. Additionally, it will function as a learning lab where trades education can take place and contractor skills can be developed. The center also has the potential to offer space for retail sales and warehouse management purposes. Moreover, it will serve as a dedicated workshop area for local construction science students and architecture students who wish to gain hands-on experience in designing and building structures using reclaimed materials.

Furthermore, this initiative seeks to support small businesses that focus on material reclamation or reuse by providing them with an incubation platform within the facility. Lastly yet importantly, this center will act as an innovation hub that encourages new practices of transforming salvaged or surplus building materials into alternative uses.

The Material Innovation Center

The city of San Antonio is actively pursuing its way to prevent building materials from landing on landfills and instead works towards implementing reuse. The Treasure in the Walls report was prepared for the City of San Antonio's Office of Historic Preservation and explores the economic and environmental benefits of a deconstruction program. The report includes findings on the building material supply chain, the economic and environmental cost of demolition, the impact of a deconstruction ordinance, and proposed recommendations for implementing a deconstruction program in San Antonio. The recommendations focus on passing a deconstruction ordinance, developing incentives for deconstruction activity, identifying barriers to material reuse, establishing workforce development programs, and creating a City-Incubated Reuse Warehouse.

Purpose of this study

Statement of Work

The primary objective of this research project is to explore and examine pertinent technologies that can optimize the usage of reclaimed materials for designing and constructing Accessory Dwelling Units (ADUs) in San Antonio. To attain a deeper understanding of this process, we propose to conduct a detailed case study that scrutinizes the life-cycle of salvaged materials from the design phase to the construction stage. Due to the intricate nature of ADUs, we suggest a two-tiered approach: an initial research phase focusing on simpler construction tasks (Stage 1), followed by a comprehensive demonstration of an ADU (Stage 2). Both stages will collectively offer valuable insights into the Salvage-to-ADU process chain at varying scales.

In Stage 1, we will concentrate on understanding the variety of available materials and their influence on design. Our focus will be the garage door project at the Material Innovation Center (MIC) and a medium-scale model, both of which will illustrate the potential of a design process rooted in salvaged materials. We will procure building materials from either a deconstruction site or through donations, and these materials will be stored at the MIC located in Port San Antonio. We will employ 3D scanning technology during the collection process, which will allow us to conduct quantitative and qualitative assessments of the materials. To simplify the design process, we will develop a digital inventory system that catalogs these materials, providing easy access to information that is critical to the designers.

Our garage door demonstration will involve the disassembly of three existing garage doors. The first will be re-designed using the existing materials, the second will incorporate reclaimed materials, and the third will feature new materials. We will document the labor effort and costs associated with each scenario to facilitate comparison. Additionally, we plan to design and construct a medium-scale model that exemplifies the concept of reclaimed construction materials. This model will address findings from the garage door project and also explore issues relevant to the development of ADUs, setting the groundwork for Stage 2.

Throughout the design, planning, and construction stages of the demonstration, we will explore the potential of digital technologies and computational design tools to increase efficiency and automation. As part of this investigation, we will develop and test design tools, visualization techniques, and construction methods that specifically target the use of salvaged materials in the design process. Our findings will be thoroughly documented in a case study report, supplemented with architectural drawings, diagrams, and photographs. The overarching question that we aim to answer through this report is: How can the Material Innovation Center facilitate the establishment of a Salvage-to-ADU pipeline and influence related housing development policies?

Building Material Reuse Case Study

Case Study Introduction

In recent years, there has been a growing emphasis on sustainability within the construction sector. As companies seek to reduce their environmental impact and adopt more eco-friendly practices, one area that often comes under scrutiny is the use of building materials (The Construction Industry Is Getting Greener: Why, How, And ... - Forbes, n.d). Materials used in building construction can have a significant impact on the environment, both in terms of resource depletion and pollution.

The use of sustainable materials in building construction can have multiple positive effects on the environment and overall efficiency of a building. These environmentally-conscious building products not only reduce material consumption and solid waste, but also decrease greenhouse gas emissions both during manufacturing and throughout the construction process.

As the development and construction materials industry continues to grow, it is crucial that we consider the impact this has on natural resources and environmental pollution. Key factors to consider include minimizing raw material waste, properly managing disposal processes, promoting renovation over replacement when possible, maintaining building components effectively, and implementing efficient waste treatment during demolition. By adopting a strategy centered around reducing, reusingThis case study aims to examine the efficacy of selected interventions on the sustainability of corporate environmental practices within the construction industry. Specifically, we will be focusing on the reuse of building materials, specifically garage doors. In order to comprehensively analyze the effects of various approaches, a comparative case study was undertaken to evaluate three different types of garage doors constructed from distinct building materials: newly sourced lumber, salvaged lumber, and reclaimed lumber. This study aimed to assess the environmental impact and resource utilization associated with each material choice.

In the first case study, the primary objective is to analyze the complete processes involved in reusing lumber for three garage doors. This includes identifying potential opportunities and challenges related to working with recycled wood. The construction of these garage doors encompasses various aspects such as structural integrity, aesthetic appeal, and integration of hardware like hinges and locks. To compare different reuse scenarios, three doors were chosen: one utilizing salvaged lumber found on-site, another using reclaimed lumber purchased from a reseller, and a third door made from new lumbe,r which serves as a baseline for traditional construction practices.

Reusable Building Materials

In the field of construction, terminology such as salvaged, reclaimed, and reused are commonly used interchangeably; however, it is important to note that each term carries a distinct meaning. In the ever-evolving realm of construction, there exists a jargon that often intertwines terms such as salvaged, reclaimed, and reused. While these words may appear to be interchangeable at first glance, it is vital to recognize their nuanced differences and meanings within the industry.

When referring to salvaged materials in building projects, we are alluding to items that have been rescued or recovered from demolition sites or other sources before they meet an untimely demise. These materials retain their original form and functionality but avoid becoming part of our planet's waste stream. By repurposing them for new structures or refurbishing existing ones, we contribute not only towards reducing environmental impact but also towards preserving resources.

On the other hand, reclaimed materials carry a distinct connotation within sustainability-driven construction endeavors. Such components encompass those taken from previous buildings or structures that are no longer in use due to various reasons like renovation plans or demolitions. The process involves gathering these discarded elements carefully so as not to compromise their integrity while simultaneously diverting them away from landfills and giving them another lease on life. Lastly yet equally significant is the concept of reusing materials - an act focused on extending products' lifespan rather than solely considering end-of-life options when addressing resource management strategies within construction workspaces. This approach prioritizes taking existing materials and incorporating them into new projects, eliminating the need for new resources to be extracted or manufacture (Dongez et al., 2021)

Salvaged Building Materials: Salvaged materials refer to those that are extracted from a site prior to or during its demolition or renovation with the intent of repurposing them in other projects.n the context of construction, salvaged lumber is wood that has been extracted from buildings, structures, or sites undergoing deconstruction, demolition, or significant renovation. This lumber might originate from a variety of architectural components, such as structural beams, supports, flooring, or siding. Salvage operations often target this wood due to its high quality, distinctive characteristics, or the unique properties offered by old-growth wood, which are seldom found in new lumber. Generally, these materials remain unaltered and are preserved in their original form. To illustrate, salvaging lumber may entail removing intact wooden beams, planks, or unique architectural elements from a site set for demolition for future application in other construction initiatives.

Reclaimed Building Materials: The term 'reclaimed' typically alludes to materials that have been sourced from a built environment and undergone some form of processing to render them reusable. Such processing could encompass cleaning, de-nailing, resawing, or other modifications.The reclamation process aims to conserve the wood's innate characteristics, frequently preserving signs of wear and age that contribute to a unique, rustic aesthetic. This reclaimed lumber can then be integrated into diverse applications in new constructions, including structural elements, flooring, furniture, and accent walls, among others. Within the field of construction, reclaimed lumber denotes wood that has previously served in a building or structural context and has subsequently been removed, processed, and earmarked for new construction purposes. For instance, reclaimed lumber may originate from old barns, factories, or warehouses and is usually processed prior to its reuse in fresh construction projects.

Reused Building Materials: 'Reuse' is a broader term, generally encompassing any materials that find multiple applications, regardless of whether they have been salvaged, reclaimed, or used again in their existing form. This may or may not entail significant processing or treatment. For example, lumber that has been directly repurposed in a new construction following the disassembly of a prior structure, without undergoing significant treatment, can be categorized as 'reused.'

In summary, while all these terms reflect strategies to mitigate waste and bolster sustainability in construction, they denote different processes and stages of material use. Salvaged materials are rescued from waste in their untouched state, reclaimed materials undergo processing to facilitate their reuse, and reused materials refer to those that are deployed multiple times, irrespective of their form.

3D Scanning for Assessment and Measurement

To accurately assess and measure the current situation, we employed 3D scanning technology. This advanced technology allowed us to capture detailed and precise digital replicas of the three garage doors made from new lumber, salvaged lumber, and reclaimed lumber. With the help of 3D scanning, we were able to capture important data such as dimensions, angles, and surface textures. This data provided us with a comprehensive understanding of the dimensions, condition, and characteristics of each garage door.

Furthermore, 3D scanning allowed us to compare and analyze the three garage doors in a highly accurate and efficient manner. By creating digital replicas of each door, we were able to visually understand their condition and identify any variations or similarities. This information was crucial in our comparative study of the building materials used. Moreover, 3D scanning apps proved to be incredibly useful during our assessment process. These apps provided us with easy-to-use tools for capturing 3D scans using just a smartphone or tablet camera. The convenience and accessibility of these apps allowed us to quickly gather data on-site without the need for bulky equipment.

The 3D scans obtained were subsequently imported into specialized software for in-depth analysis and precise measurements. The utilization of 3D scanning technology was immensely valuable in our comparative examination of three different garage doors constructed from fresh timber, salvaged timber, and reclaimed timber. Within our 3D modeling environment, the entire structure of the garage was remodelled using the acquired 3D scans along with supplemental manual measurements.

Three Types of Garage Doors

In our comparative study, we focused on three types of garage doors: those made from new lumber, salvaged lumber, and reclaimed lumber. The garage door made from new lumber represents the conventional approach of using freshly harvested wood for construction. On the other hand, the garage door made from reclaimed lumber incorporates wood that has been repurposed or recycled from other sources, such as deonstructed houses or old storages. Lastly, the garage door made from salvaged lumber utilizes wood that has been on site already from the previous dissassembled garage doors.

In our comprehensive comparative study, we delved into the characteristics and benefits of the three distinct types for constructing garage doors: those crafted from new lumber, salvaged lumber, and reclaimed lumber. By closely examining each type, we were able to gain a deeper understanding of the diverse approaches to constructing these essential structures.

New Lumber Garage Door

The conventional approach is exemplified by the use of freshly harvested wood for building garage doors. This method represents the widely adopted practice in which new timber is sourced specifically for construction purposes. While this approach has been traditionally favored due to its availability and ease of procurement,it may not necessarily align with sustainable practices. The newly acquired wood for the project was sourced from a local hardware store and primarily consisted of whiteboard material. However, there were instances where some of the boards had suffered damage during production or transportation. As a result, it became necessary to inspect and sort through the available stock before making a purchase in order to ensure that only high-quality wood was obtained.

This process of sorting serves as an important quality control measure to minimize potential drawbacks caused by damaged or substandard materials. By carefully scrutinizing each piece of wood, builders can identify any defects such as cracks, warping, or other structural issues that could compromise the integrity and longevity of the finished product.

Reclaimed Lumber Garage Door

The lumber for the reclaimed garage door was sourced from a local reseller in San Antonio who obtained the lumber from a decosntrcuted building. Acquiring reclaimed lumber involves several stages, from sourcing to processing. The process varies depending on the type of structure the wood is being reclaimed from and the intended use for the wood after reclamation. However, the general process can be summarized in the following steps:

Sourcing: The first step is to identify suitable sources of reclaimed wood. This could be old barns, warehouses, factories, residential homes, or other structures slated for deconstruction. The age, condition, and type of wood used in these buildings are all factors to consider when sourcing reclaimed lumber.

Permission and Safety: Next, permission must be obtained from the owner of the structure to remove the wood. In some cases, a structural engineer or similar professional might need to evaluate the building to ensure it's safe to deconstruct.

Deconstruction: Unlike demolition, which destroys the building quickly, deconstruction is a slower process designed to preserve as much of the material as possible for reuse. The building is taken apart piece by piece, with the wood carefully removed to avoid unnecessary damage.

Sorting and Inspection: Once the wood has been removed, it's sorted based on factors such as type, size, and quality. It's also inspected for issues that could affect its reuse, such as insect damage or rot.

Processing: After sorting and inspection, the wood is processed for reuse. This typically involves cleaning, removing nails and other hardware, and treating the wood for insects or decay if necessary. Depending on the intended use, the wood may also be milled into boards or other shapes.

Storage and Distribution: Finally, the reclaimed lumber is stored until it's sold or used. Many reclaimed wood companies have showrooms or warehouses where customers can browse and purchase the lumber.

One of the key aspects of this process is that it's labor- and time-intensive and requires expertise in handling and processing wood. This can contribute to the cost of reclaimed lumber, but also adds to its unique appeal and environmental benefits, as it keeps usable materials out of the landfill and reduces the demand for new lumber.

The use of ratchet straps to remove the crook from the boards, followed by fastening screws into the front of the wood to secure them in place, is a common method employed during deconstruction processes. Ratchet straps offer an efficient and effective means of pulling out any deformities or irregularities present in the timber. By applying tension with these straps, it becomes possible to straighten bent or warped boards, ultimately enhancing their reusability.

Once the crook has been corrected using ratchet straps, utilizing screws to affix them firmly helps maintain their desired alignment. This step plays a crucial role in ensuring stability and structural integrity when repurposing salvaged lumber for construction purposes.

Salvaged On-Site Lumber Garage Door

The use of salvaged lumber for constructing garage doors offers a very sustainable alternative compared to the conventional approach of using new lumber. Salvaged lumber refers to wood that has been reclaimed or salvaged from previous structures, such as old buildings or in our case from deconstructed garage doors.

The salvaged doors were constructed in just four hours. With two other bays having been replaced, this left two old sets of doors completely unused. Since the only part of the doors that was decaying was the bottom due to overexposure to rain, the idea was to take the tops of the now unused doors and replace the bottom of the existing doors. The existing doors were cut in half to be prepped for the new bottoms.

A crucial point to note is that the labor costs involved in deconstruction and processing of salvaged lumber tend to exceed those associated with new timber. Furthermore, the availability of salvaged material is often limited, contributing to its higher market price when compared to new materials. However, if deconstruction were to become a more widespread practice, leading to a greater influx of salvaged material, the cost of these materials might decrease. This could potentially render salvaged materials a cost-effective alternative to new ones (Davis, 2012).

It's worth mentioning that labor costs associated with deconstruction and processing of salvaged lumber are quite high compared to new timber. Additionally, there may be shortages and limited availability of salvaged material which contribute towards their higher price relative to new materials on today's market. However, it is argued that if deconstruction became more common practice and a greater supply of salvaged material became available, the cost of salvaged materials could potentially decrease, making them a more viable alternative to new materials (Davis, 2012).

In the case of the salvaged doors the material was already on site and was almost dimensioned perfectly. The only challanges were the proper cut, which required some preperation time and expertise.

Comparative Results and Findings

The comparative study of the three garage doors, one made from new lumber, one made from salvaged lumber, and one made from reclaimed lumber, revealed that there are important considerations to be made when choosing between these different types of materials. Firstly, the cost of reclaimed lumber is currently higher than that of new lumber due to the labor-intensive process involved in deconstruction and processing. This does not only include a little bit more extensive construction time but also more time consuming efforts during the design as well as material aquisition.

Firstly, it was found that while the salvaged lumber used for the door construction was readily available on-site, there were challenges associated with the proper cutting and preparation of the salvaged materials.

Environmental and Economic Benefits

ADU Models

The concept of reusing local materials in the construction of Accessory Dwelling Units is particularly intriguing due to their compact size and integration into existing infrastructure. It is possible that salvaged or reclaimed materials from a deconstructed full house within a neighborhood could provide enough resources to build an ADU. However, further research is necessary to thoroughly assess the potential advantages and limitations associated with utilizing these types of materials for ADUs.

When considering the utilization of salvaged or reclaimed materials for ADUs, a challenge arises due to their temporary nature. Since ADUs are often installed temporarily before being removed, it may affect the feasibility of incorporating salvaged or reclaimed components. To overcome this challenge, there is an increasing interest among contemporary researchers and practitioners in adopting "Design for Disassembly" principles when designing ADUs. By intentionally factoring disassembly into the design process, it becomes more convenient to salvage and reuse materials during future deconstruction endeavors.

In the realm of sustainable building design, there is an intriguing prospect in incorporating deconstruction practices to utilize local resources for affordable housing solutions like Accessory Dwelling Units. By effectively repurposing materials and employing mindful design strategies, it is possible to reduce waste production significantly while simultaneously fostering environmental sustainability on numerous fronts.

In this case study, three different demonstrators were constructed to showcase the reuse of reclaimed materials. The main focus was on a structural lumber framing system. The first demonstrator featured a conventional framing system with a cladding made from salvaged lumber. This showcased how traditional construction methods can incorporate reclaimed materials for sustainability. The second demonstrator highlighted a truss system that could be prefabricated and easily assembled on site. This demonstrated the efficiency and speed at which reclaimed materials can be utilized in construction. For the third demonstrator, modular construction techniques were employed, utilizing reclaimed lumber to create stackable boxes that could be quickly and easily assembled. This example showcased innovative ways of using reused materials for fast assembly. Overall, these three demonstrators serve as excellent examples of different approaches to incorporating reused materials in contemporary building construction practices while emphasizing their various applications in promoting sustainability within the industry.

Access to Materials

The practice of resource utilization, particularly in the context of salvaging timber, underscores the broader principles of sustainability and conservation. As the global demand for timber continues to rise, these practices become not just beneficial, but also necessary for resource management and environmental stewardship (Montague et al., 2023).

When a building is demolished, the resultant debris often consists of various types of wood, from structural beams to interior elements. Instead of relegating this to landfills, conscientious demolition practices can identify and separate valuable pieces of timber for future reuse. This reclaimed lumber often bears unique aesthetic features and history that new wood lacks, contributing to the character and appeal of the final product.

The act of deconstruction provides a similar but more purposeful avenue for reclaiming wood. Unlike demolition, deconstruction entails the careful disassembly of structures, where the intent is to maximize the recovery of usable materials. This process is often more labor-intensive but results in a higher yield of salvageable timber, which, again, is not only economically advantageous but also environmentally friendly. The extracted timber can be treated, if necessary, and reprocessed for reuse in various ways, such as in building new structures or creating unique furniture pieces.

Construction projects typically generate a substantial amount of waste, including discarded timber from cut-offs, over-ordering, or design changes. By implementing sustainable practices like efficient material planning, site waste management plans, and just-in-time ordering systems, the amount of waste can be significantly reduced. Any surplus or scrap wood that still results can be repurposed or upcycled into smaller items, ensuring the most efficient use of the material.

Through these methods, reclaimed and salvaged timber is obtained from a variety of contexts, each with its unique challenges and benefits. Together, they contribute to a circular economy where waste is minimized, resources are efficiently utilized, and the environmental impact is mitigated. This highlights the importance and value of the timber resource, promoting its sustainable management and conservation for future generations.

A fundamental problem with building material reuse raised by many contractors is that

customers do not want used material in new buildings. Other common problems

concerning building material reuse include:

• dimension problems - rehabilitating a house may require finding the right

cabinet to fit existing walls. Locating reused materials that fit into an existing

space may be more difficult than purchasing a new product;

• inconsistency in supply - building new houses with used materials requires

customization, which results in extended lead times and potential delays in construction schedules;

• lack of design standards - there is a lack of standardized guidelines and regulations for utilizing reclaimed or salvaged materials in construction projects, making it difficult for architects and designers to confidently incorporate these materials into their designs

Materials for Demonstrators

The ADU prototypes require higher amounts of materials compared to the garage door study. The acquisition of salvaged timber from various sources, such as previous building demolitions, deconstruction activities, or ongoing construction projects, serves as a prime example of the ability to obtain resources from these different origins. This demonstrates the diverse contexts in which reclaimed timber can be sourced.

Salvaged Demolition Materials

The initial batch of timber was sourced from a storage facility located at the Kelso House in San Antonio. These particular timbers consisted of dimensions measuring 2" by 8" and were obtained through salvage efforts following a demolition project conducted at the Pearl. Careful deconstruction methods were employed to salvage these lumber pieces, ensuring their suitability for reuse in the construction of ADU prototypes. The salvaged lumber exhibited some variability in terms of lengths and sections, as is common with reclaimed materials. This variability can present challenges in terms of supply and fitness for purpose in mainstream construction, as reclaimed whole members tend to be shorter in usable lengths and have smaller effective sections. Reclaimed whole members generally tend to have shorter usable lengths and smaller effective sections compared to newly manufactured counterparts (Rose et al., 2018). Furthermore, the salvaged lumber obtained from the storage facility lacked warranties and certifications, which may limit its demand in mainstream construction where certainty and quality assurance are highly valued.

This lack of consistent dimensions may limit their use in traditional construction settings where standardized specifications are highly valued. However, given appropriate design considerations and modifications tailored towards working with reclaimed materials, innovative solutions can be developed.

Reclaimed Deconstruction Materials

The process of deconstruction - carefully dismantling structures to reclaim materials that would otherwise be discarded - offers a valuable opportunity to salvage reusable timber. The Material Innovation Center houses material sourced from a deconstruction training event held in San Antonio in October and November 2022. This event, organized by the Office of Historic Preservation and the San Antonio River Authority, was a Certified Deconstruction Contractor Training program, which was conducted by Re:Purpose Savannah. The program was specifically designed to teach contractors how to deconstruct early 20th-century wood-framed structures.

The structures used for training were originally constructed in the early 1900s as housing for workers and their families from a nearby ranch. As the trainees carried out the deconstruction, they discovered markings on the lumber that provided valuable historical information about the structures and the lumber company involved in their construction, Hillyer-Deutsch-Jarratt Lumber Co. This discovery illuminated not only the history of these particular structures but also contributed to the broader understanding of San Antonio's development history, establishing connections with the individuals who constructed the city's homes and businesses. This kind of information, which typically would be lost during standard demolition, was preserved due to the deconstruction process.

This initiative forms part of the city's Deconstruction and Circular Economy Program. The program's goal is to preserve historical materials and promote sustainable practices. The materials sourced from this training event are now stored at the Material Innovation Center, contributing to the center's mission.

Reused Construction Waste

In addition to demolitions and deconstruction, another potential source of salvaged timber for reuse is ongoing construction projects. The study also included a prominent construction site located on Josephine Street in San Antonio as the third source of materials. This site proved to be a significant contributor of dimensional lumber, which is commonly used for temporary structures like fences and staircases during construction processes.

However, it should be noted that these reclaimed lumber pieces from construction sites are often considered unsuitable for large-scale construction projects that require high-quality materials adhering strictly to structural integrity standards. This is primarily due to time constraints and the potential damage incurred during their previous use.

To address this issue, sustainable practices can be implemented within construction activities by integrating meticulous planning and efficient material usage. By doing so, excess or unused structural elements can be repurposed rather than being disposed of wastefully. Ultimately, the goal is to reduce the demand for new materials by maximizing the use of salvaged and reclaimed lumber in construction projects.

Recycled Fabrication Waste

The construction industry is progressively shifting towards prefabrication processes, a trend prominently observed in the timber products sector. Prefabrication techniques not only optimize operational efficiency but also minimize timber waste, thereby enhancing business profitability. Despite these improvements, waste material is an inevitable byproduct of these processes. Various strategies are adopted to repurpose this waste, such as transforming leftover pieces from post and beam fabrication into energy resources or farming material. However, a significant portion still finds its way into landfills.

Our study focuses on salvaging the residual cut pieces generated during post and beam fabrication. We noticed that a large quantity of dimensional lumber could be recovered. However, the dimensions varied slightly from standard construction lumber sizes. To ascertain the potential reuse of these lumber blocks, we undertook a systematic assessment of their dimensions and structural functionality.

We harnessed the precision of 3D scanning technology to accurately measure the salvaged lumber blocks. This advanced method provided detailed analysis of each block's structural properties, enabling an in-depth understanding of their potential functionality. With the data collected from the 3D scans, we created digital models of each lumber block within a Computer-Aided Design (CAD) environment. These digital counterparts mirrored the physical stock of lumber blocks, presenting an exact replica of each item.

By utilizing cutting-edge technologies like 3D scanning and CAD software tools, we can perform a comprehensive assessment of reclaimed materials such as lumber blocks. This innovative approach empowers us to explore their potential for reuse in a range of applications, thereby further reducing waste and promoting sustainability in the construction industry.

Evaluation of RECYCLED Materials

In addition to the sourcing of salvaged timber, it is equally important to consider the quality and condition of the materials (Chini & Acquaye, 2021). The trade and acceptance of reclaimed lumber products greatly depend on rigorous quality control measures. It is important to maintain high-quality standards for recycled lumber to build confidence among stakeholders involved in the reuse of dimensional lumber in construction.

Previous research (Falk & Green, 1999) suggest that heart checks result in a reduction in the modulus of rupture for recycled timber beams, while having minimal impact on the strength of recycled timber columns. It has been observed that dimensional lumber obtained from deconstructed buildings tends to be one grade lower than freshly sawn lumber due to damage incurred during the dismantling process. Since the value of lumber is closely associated with its quality, assessing the grading levels of timber derived from these structures will prove instrumental in determining potential reuse options and market valuation.

In the United States, the visual grading of lumber is generally conducted according to the standards set by the American Softwood Lumber Standard (Voluntary Product Standard PS 20-70), developed by the National Institute of Standards and Technology (NIST) and the American Lumber Standard Committee (ALSC).

This standard covers the sizes, grading rules, and moisture content to which softwood lumber is normally manufactured and is used as a reference for the oversight of the accreditation program by the ALSC. The grades established under this standard depend on various factors such as the species of wood, its intended use, and the visual characteristics of the lumber, including knots, grain patterns, and other natural defects.

However, for reclaimed or recycled lumber, the grading process can be more complex due to factors such as nail holes, saw marks, and weathering. At present, there isn't a widely accepted standard for grading reclaimed lumber. Some organizations are working on developing such standards, but in the meantime, the grading of reclaimed lumber often depends on the judgement of experienced professionals in the field.

Several proposed methods for visual grading include creating a distinct "Reclaimed" lumber species group, which would be treated as a unique species within the National Design Specification (NDS) for Wood Construction with design values reflecting the strength reduction. Another approach is applying a reduction factor to current lumber design values based on the strength reduction percentage. Some grading agencies suggest a one visual grade reduction in properties for reclaimed lumber. Alternatively, reclaimed lumber could be included in a lower strength NDS species grouping, as the bending strength of certain reclaimed lumber like Douglas-fir would meet the requirements of the Western Woods species grouping.

The processing of reclaimed wood often involves a series of steps, including de-nailing, cleaning, kiln drying, milling, and installation. These steps help ensure the quality and safety of the reclaimed wood, particularly kiln drying, which is essential for removing moisture and potential pests from the wood. The importance of this step is such that it can distinguish between good and great reclaimed wood companies. While there might not be specific grading standards for reclaimed lumber, the general principles of wood grading considering aspects like the presence of defects, the size of the wood, and other factors, can still be applied. It's also crucial to ensure the reclaimed wood has been properly processed to ensure it's safe and suitable for its intended use.

The lumber that was used for the demonstrators was either pine or douglas fir, both of which are commonly found in construction projects. Bothe are softwoods that offer strength and durability, making them suitable for structural applications. Previous study already pointed out the structural capacity of reused lumber from deconstruction or salvaged from demoltions sites.

During our selection process the lumber pieces were visually inspected and graded based on their condition. The salvaged lumber showed signs of previous use, including nail holes and cuts, but its structural integrity was still intact.

The compression tests conducted for this study showed similar resulst to the findings of previous research, indicating that salvaged and reclaimed lumber can still meet the necessary structural requirements for construction. In conclusion, the evaluation of salvaged and reclaimed materials is crucial for maximizing their use in construction projects.

Framing with Reclaimed Materials

Stick framing is one of the most common construction techniques for single family houses in San Antonio. It became widely adopted as a construction method for residential and commercial buildings during the 1830s and 1840s. Stick framing involves constructing the structural frame of a building using individual wooden members, such as studs, joists, and rafters, which are assembled on-site. This method replaced earlier techniques like timber framing, which utilized larger, handcrafted beams and joints. Stick framing offered several advantages, including faster construction, lower costs, and greater flexibility in design. It revolutionized the construction industry and continues to be the predominant framing method used in the United States today.

From an engineering perspective, ensuring the performance of reclaimed lumber in service is crucial, which requires the establishment of suitable design values (Falk et al. 2012). Given that reclaimed lumber has been found to have lower strength than new lumber, adjustments in lumber use provisions and design codes are necessary.

To address this difference in building with reclaimed lumber the easiest way is to increase the cross section of the used pieces. In our case we constructed the conventional stick framing, that usually would have been made from 2 by 4s, but instead used reclaimed lumber with larger dimensions, such as 2 by 6s or even 2 by 8s. Moreover, one can easily reduce the distance between the sticks. This modification ensured that the structural integrity and load-bearing capacity of the framing system were maintained.

The use of reclaimed materials in construction poses challenges compared to conventional framing. One primary concern is the condition of the wood, as it may have defects such as warping or being non-straight. Additionally, reclaimed lumber tends to be harder than new lumber due to its age and previous use. These characteristics can make working with salvaged timber more difficult and require special attention during design and construction processes.

To explore these challanges a prototype was build from salvaged wood. The design consist of three walls, one of which includes a reclaimed window and partial cladding. The purpose of this prototype was to assess the feasibility and performance of using salvaged lumber in a real construction scenario. The walls were assembled and put together at the site of the Material Innovation Center.

By addressing these technical barriers through rigorous quality control measures and innovative building techniques, there is an opportunity to enhance the acceptance and trade of recovered dimensional lumber in the construction industry.

Modular Truss from Reclaimed Lumber

Another demonstration project that was undertaken as part of this case study involved the construction of a modular truss system using reclaimed lumber. This modular truss system was designed to be easily assembled and disassembled, making it ideal for temporary structures or buildings that may need to be relocated in the future. The modular truss system was constructed by carefully selecting and preparing salvaged lumber to ensure its structural integrity. The designed truss system primarily addresses the issue of varing dimension commonly found in reclaimed lumber. Therefore, the truss elements are designed as discrete modular pieces with a hight of 14" (35.5cm) and a maximum length of 48" (121.9cm). It was important to design the modular system so that each module can be carried by maximum two persons to enable easy on site assembly. The elements are intended to be prefabricated at a factory or the Material Innovation Center and then transported to the construction site for assembly.

The use of modular construction not only offers the advantage of easy assembly and disassembly, but also provides flexibility in design and future repurposing.Besides the assembly the modules offer also various configurations, making them feasible for future repurposing into new structures. By offering a reversible connection between the truss pieces using mechanical fasteners, such as screws or bolts, the modular truss system allows for easy disassembly and reassembly without causing damage to the reclaimed lumber. Especially, for ADUs that might only be temporary structure the easy disassembly and potential reselling of the parts may offer benefits. One can imagine that such building systems provided for affordable housing throughout a city. Once an ADU or any structure build from thee modules can serve as donor for a new structure.

The modular system is constructed using a double truss structure that is interconnected by cross braces. This configuration serves the purpose of enhancing both stability and strength across the entirety of the system. While such an approach may seemingly be perceived as less material-efficient due to its additional layer, it can also be considered as an adaptation aimed at addressing the inherent unpredictability associated with reclaimed lumber. Given that material defects or weaknesses might not always be readily apparent, this layered structure plays a pivotal role in accommodating such uncertainties while ensuring optimal performance of the overall system. Moreover, the presence of these layered truss elements offers another advantage: self-alignment during assembly. Consequently, fitting between modules becomes considerably easier and more straightforward.

The prototype was constructed by utilizing a limited set of modules, specifically consisting of straight truss pieces, corner pieces, and truss-to-corner connectors. A total of 24 such modules were employed in the assembly process, which could conveniently fit within two pickup trucks. This modular approach to construction exhibits several benefits including simplified logistics and ease of transportation due to the compact nature of these standardized components.

An entire ADU could potentially be constructed using this modular truss system made from reclaimed lumber. Depending on the size and design of the ADU, a larger quantity of modules would be required. Illustrated on the next page is an ADU with a pent roof. The pent roof ADU design showcases the versatility and adaptability of the modular truss system. The design still utilizes the straight truss and corner pieces, additionaly it requires two different types of modules for the roof structure: ridge truss pieces and gable-end truss pieces. These additional modules allow for the creation of a sloping roof that is commonly seen in residential structures. By changing these additional pieces the modular system can be costumized easily to meet different roof slope criteria.

The use of reclaimed lumber in the construction of this modular truss system not only showcases the potential for structural reuse but also highlights the importance of innovative design

Reuse Stack Reuse

The rise in costs and the limited availability of construction labor in recent times have placed significant strain on the housing market, causing a decrease in affordability when it comes to building houses. In order to address this issue, one potential solution is to explore the use of recycled materials and modular construction. This approach not only helps reduce material expenses but also lessens the burden on transportation infrastructure within local communities. Additionally, it becomes crucial to reassess current construction methods and strategies with an aim to enhance overall efficiency.

One method of achieving such efficiency is the adoption of prefabricated, modular systems. This case study focuses on the efficient and rapid assembly of prefabricated structural components. By manufacturing the modules offsite and transporting them to the construction site, construction timelines can be significantly shortened and labor costs reduced. This approach represents a paradigm shift in construction, where the bulk of the work shifts from the site to the manufacturing facility, leading to increased productivity and less disruption to the local environment.

The proposed building blocks for walls and the slab construction system are designed to be stackable, bearing similarity to Lego blocks. This discrete logic simplifies the construction process and renders complex assembly instructions unnecessary. The self-supporting blocks require no falsework, further simplifying the construction process.

Moreover, these building blocks serve a dual purpose, acting as construction scaffolding during the assembly of the roof slab. Skilled construction workers were able to utilize the horizontal lumber beams of these blocks as practical steps, facilitating their access to and from the roof area and enabling them to execute their assigned tasks with precision.

Although the block design results in a thicker wall layout, the space between the studs offers multifunctional possibilities. It can be utilized for insulation, plumbing, storage, among other purposes, transforming what might be seen as a design limitation into a functional advantage.

The use of prefabricated wall systems and modular construction methods not only streamlines the construction process but also allows for greater flexibility in design. By decoupling the design and construction processes, architects and engineers can explore innovative design possibilities without being constrained by traditional construction limitations. The used blocks offer vast possibibilities of combinatorics to creat an ADU as long as the design copes with the block dimensions. Consequently, the final building product can be a harmonious blend of aesthetics, functionality, and sustainability.

Prefabricated wall systems and modular construction methods have gained significant popularity in the construction industry due to their ability to streamline the building process while also allowing for greater design flexibility. By separating the design and construction phases, architects and engineers are able to explore innovative possibilities without being limited by traditional constraints. This approach offers a wide range of combinatorial options when utilizing blocks, such as creating an Accessory Dwelling Unit, as long as the designs adhere to block dimensions.

The result is a final building product that harmoniously combines aesthetics, functionality, and sustainability. The use of prefabrication techniques not only saves time but also reduces waste generated during construction activities. According to research , noise levels and disruptions caused by nearby buildings are significantly reduced by approximately 30-50% with prefabricated modular constructions compared to traditional methods (Yao et al., 2020).

Worforce Training and Augmented Reality

In order to successfully implement the use of prefabricated modular construction methods, it is crucial to provide adequate training and education to the workforce involved (Zhang & Tsai, 2021). Better workforce training in the construction industry, especially in the realm of Accessory Dwelling Units (ADUs), has numerous benefits. Skilled workers are essential for any construction project, but more so for ADUs, which require workers to quickly adapt to a new construction plans due to the small size of the projects. Training helps workers to better understand the intricacies of ADU construction and equips them with the skills to efficiently and accurately complete their work. One method that can enhance workforce training in the construction industry is through the use of augmented reality technology (Nassereddine et al., 2022).

Quality training enhances workers' efficiency and productivity by helping them understand the best practices for constructing ADUs. This can reduce the time it takes to complete a project and can also minimize mistakes that could lead to costly rework. This is particularly important for ADUs, which are often built in tight spaces or in residential neighborhoods where delays or mistakes can have significant impacts.

Training can also improve worker safety. Construction is a dangerous profession, and ADUs often involve working in close quarters or in residential areas with unique safety considerations. By teaching workers how to safely handle equipment and materials, and how to anticipate and mitigate risks, training can reduce the occurrence of accidents and injuries on the job.

As for the use of augmented reality (AR) in workforce training and during ADU construction, it offers transformative potential (Tan et al. 2022). AR can provide a visual and interactive method of training, allowing workers to learn in a more engaging and effective manner. For instance, trainees can use AR to visualize the steps of a process, practice skills in a safe and controlled environment, or explore a 3D model of an ADU before they start building it.

During construction, AR can be used as a tool to assist workers. For instance, AR can overlay digital images onto the real world, showing workers exactly where components should go or how they should be assembled. This can reduce the likelihood of mistakes, speed up the construction process, and ensure that the final product aligns with the design specifications.

AR can also facilitate better communication and collaboration among project stakeholders. For example, architects, engineers, and construction workers can use AR to visualize and discuss aspects of the ADU design, helping to ensure everyone has a clear understanding of the project and their roles in it. This can help avoid misunderstandings or miscommunications that could lead to delays or design discrepancies. In this study AR was used to effectivly communicate construction steps. A 3D model of the ADU to be constructed is projected onto the site, which potentially could also be used during design decisions by the property owner to chose placement and orientation of the ADU. During assembly of the prefabricated blocks, the AR system displayed step-by-step instructions and visual cues, helping the workers to accurately position each block and ensure proper alignment.

In summary, embracing prefabrication and modular construction offers an effective approach towards mitigating the challenges faced in the housing market. It promotes more sustainable practices through the use of recycled materials, enhances construction efficiency, and offers greater design flexibility. This approach could revolutionize the construction industry and lead the way towards more sustainable and affordable housing solutions.

Conclusion and Recommendations

The objective of the studies conducted in this report was to explore the ways in which the Material Innovation Center can facilitate the establishment of a Salvage-to-Accessory Dwelling Unit pipeline, as well as develop appropriate housing development policies. The case study on utilizing salvaged and reclaimed lumber in ADU construction provides significant insights into its advantages. However, it is important to acknowledge that there are certain challenges associated with accessing and using these materials for construction projects. Nevertheless, constructing an ADU at a small scale presents an excellent opportunity for experimentation due to its limited material requirements and relatively lower structural demands compared to larger buildings. Based on the findings of this study, it is recommended that further research and development be conducted to explore the feasibility and potential benefits of using salvaged and in a proper setup prefabrication center as well as appropriate training for the on-site construction.

Further studies should also be conducted to assess the long-term durability and performance of buildings constructed using salvaged and reclaimed materials. This will help evaluate the structural integrity and ensure that these materials can meet the necessary building standards and regulations.

In conclusion, the comparative study of three garage doors made from new lumber, salvaged lumber, and reclaimed lumber highlights the potential for utilizing reused materials in construction projects. The most time and cost effective method was to utilize on-site salvaged materials which renders a strong case to reuse materials as local and similar to ther previous utility. Although the door made from reclaimed materials was slightly more expensive and time consuming compared to the door made from new lumber, it is still a more sustainable choice due to its significant reduction in environmental impact. The machinery and transportation for each new piece of lumber not only contributes to carbon emissions but also depletes natural resources. However, the reclaimed resellers still have potential to improve their inventory system to provide better information about available stocks. Especially larger quantities of materials for instance for ADU projects need better coordination about what is available. Thherefore, we proposed a digital inventory system that allows designers, contractors, and clients to easily access information about salvaged and reclaimed materials, their availability, and specifications. This information could be presented in form of an online database or platform that allows users to search for specific materials, view their dimensions and condition, and make inquiries about pricing and availability. This digital inventory system would not only help increase the demand for salvaged and reclaimed materials by providing easy access to information, but also streamline the process of sourcing and procuring these materials for construction projects.

The procurement of new materials at a local home builder shop provides a quicker and more streamlined process for construction projects. However, even when shoping for new lumber the quality control of the lumber requires detailed inspection to find the highest quality lumber pieces.

Additionally, the study emphasizes the importance of incorporating considerations for using salvaged and reclaimed materials into the design process.

In another study by Denhart (2010), who focused on deconstruction programs after hurricane Katrina hit in 2005, reclaimed materials from four deconstructed houses were reported upon.

The careful sourcing and utilization of salvaged timber from various origins demonstrates the ability to acquire valuable resources in a variety of contexts. These sources include past building demolitions, deconstruction activities, or ongoing construction endeavors. By exploring these diverse avenues for obtaining salvageable timber, we can maximize resource efficiency while minimizing environmental impact. It is important to recognize the potential value of repurposing materials that would otherwise go to waste. This approach aligns with sustainable principles by reducing the need for virgin timber extraction and promoting circular economy practices in the construction industry. This approach not only reduces overall resource consumption but also promotes sustainability by extending the lifespan of building materials through their re-use.

By implementing sustainable practices like efficient material planning, site waste management plans, and just-in-time ordering systems, the amount of waste can be significantly reduced. Additionally, incorporating salvaged and reclaimed timber into construction projects not only helps conserve natural resources but also promotes the concept of circular economy.

However an alternative option exists through utilizing salvaged or reclaimed lumbers in constructing garage doors. Surprisingly though it's possibility being more evident today than ever before their usage remains somewhat limited within industry standards due mainly to several prevailing challenges such as insufficient demand for recycled materials alongide inadequate design guidelines coupled with stringent building regulations that act as barriers preventing widespread implementation. It should also be noted while feasible certain factors surrounding deconstruction methods greatly impact how easily a structure can be dismantled post-use ultimately determining reusability potential.To comprehensively examine these possibilities we must acknowledge advancements made in reverse engineering technology; particularly 3D scanning which allows objects and places to transform seamlessly into digital three-dimensional

Prototypes

From a technical standpoint, this project underlines the concept of Design for Disassembly (DfD), which is an increasingly important paradigm in sustainable architecture and construction. The easy assembly and disassembly of the modular truss system, ensured by the use of reversible mechanical fasteners, facilitates the eventual decommissioning and repurposing of the structure. Such a design strategy increases the potential lifespan of the materials, enabling multiple life cycles of use.

This principle of DfD also aligns with the increasingly popular notion of buildings as 'material banks', where components are not considered as permanent fixtures, but rather as temporary deposits. This perspective underpins the concept of circular economy in construction, where the focus is on resource efficiency and the extension of the service life of materials and components (Kanters, 2018).

From a logistical perspective, the modular truss system is particularly beneficial. The standardization of elements reduces complexity in construction and inventory management. Moreover, the use of a limited set of module types enhances the feasibility of transportation, as witnessed in the case study where the entire assembly could fit within two pickup trucks. This efficiency in logistics can translate into significant cost and time savings during the construction process.

To overcome these challenges and enhance the supply of secondary timber for construction, it is crucial to establish design standards that consider the characteristics of salvaged and reclaimed timber. Design standards for salvaged and reclaimed timber would provide certainty regarding the mechanical characteristics, usability, and fitness for purpose of these materials. Additionally, overcoming the barriers posed by prohibitive building regulations is crucial for increasing the demand and utilization of reclaimed structural components.

There is a need for standardized design guidelines and building codes that specifically address the use of salvaged and reclaimed lumber in construction.

References

Falk, R. H., Cramer, S., & Evans, J. (2012). Framing lumber from building removal: How do we best utilize this untapped structural resource? In Forest Products Journal. https://doi.org/10.13073/0015-7473-62.7.492

Nassereddine,H.,Schranz,C.,Hatoum,M. & Urban,H.(2022).Mapping the capabilities and benefits of AR construction use-cases: A comprehensive map. Organization, Technology and Management in Construction: an International Journal,14(1) 2571-2582. https://doi.org/10.2478/otmcj-2022-0003

Tan, Y., Xu, W., Li, S., & Chen, K. (2022). Augmented and Virtual Reality (AR/VR) for Education and Training in the AEC Industry: A Systematic Review of Research and Applications. Buildings, 12, 1529. https://doi.org/10.3390/buildings12101529

Yao, F., Liu, G., Ji, Y., Tong, W., Du, X., Li, K., Shrestha, A., & Martek, I. (2020). Evaluating the environmental impact of construction within the industrialized building process: A monetization and building information modelling approach. International Journal of Environmental Research and Public Health. https://doi.org/10.3390/ijerph17228396

Davis, J. E. B. (2012). Suitability of salvaged timber in structural design.

Denhart, H. (2010). Deconstructing disaster: Economic and environmental impacts of deconstruction in post-Katrina New Orleans. Resources, Conservation and Recycling. https://doi.org/10.1016/j.resconrec.2009.07.016

Kanters, J. (2018). Design for deconstruction in the design process: State of the art. In Buildings. https://doi.org/10.3390/buildings8110150

EPA. (2019, January 1). Advancing sustainable materials management: Facts and figures report. . United States Environmental Protection Agency. https://www.epa.gov/facts-and-figures-about-materials-waste-and-recycling/advancing-sustainable-materials-management
Council, C.. (2021, December 17). 2022-2031 Housing Plan for the City of San Antonio and Bexar County. San Antonio. https://www.sanantonio.gov/Portals/0/Files/NHSD/Coordinated%20Housing%20Web-page/CHS/SHIP_Approved.pdf?ver=2021-12-20-104249-810
The Construction Industry Is Getting Greener: Why, How, And ... - Forbes. (n.d). https://www.forbes.com/sites/sap/2021/08/25/the-construction-industry-is-getting-greener-why-how-and-whats-changing/
Dongez, N., Manisa, K., & Basdogan, S.. (2021, December 28). Tendency to Circular Economy. https://scite.ai/reports/10.17831/enqarcc.v18i2.1089
Montague, I., Craig, M., & Shmulsky, R.. (2023, January 1). From Refuse to Reuse: How Much do Consumers Know about the Reclaimed Lumber Industry?. Forest Products Journal, 73(1), 43-52. https://doi.org/https://doi.org/10.13073/FPJ-D-22-00053
Rose, R., Colin et al. (2018, November 9). Cross-Laminated Secondary Timber: Experimental Testing and Modelling the Effect of Defects and Reduced Feedstock Properties. https://scite.ai/reports/10.3390/su10114118
Chini, A. R., & Acquaye, L.. (2021, January 1). Research Article: Grading and Strength of Salvaged Lumber from Residential Buildings. Environmental Practice, 3(4), 247-256. https://doi.org/https://doi.org/10.1017/S1466046600002805
Falk, R. H., & Green, D.. (1999, January 1). Stress Grading of Recycled Lumber and Timber. Structures Congress - Proceedings. https://www.fpl.fs.usda.gov/documnts/pdf1999/falk99d.pdf
Zhang, K., & Tsai, J.. (2021, October 7). Identification of Critical Factors Influencing Prefabricated Construction Quality and Their Mutual Relationship. Sustainability, 13(19), 11081. https://doi.org/10.3390/su131911081