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Addressing Sustainability through Alternative Builds


Background

The construction industry is historically slow-moving when it comes to implementing new efficient and sustainable practices. However, several Habitat affiliates are shifting this standard through alternative models of building and bringing innovative solutions to the industry.


By thinking outside of traditional building standards and using features such as local climate and materials to their advantage, these Habitat affiliates created unique solutions to improve the efficiency and sustainability of their builds.


“We need to empower ourselves and the next generation to

have the most impact. We have to fundamentally shift the paradigm of how construction works in this country...”

– Gunnison Valley affiliate


Straw Bale Homes


One focus of Gunnison Valley Habitat in Colorado is resource conscious construction. They seek to avoid foam materials, reduce concrete or use emerging concrete technology, and employ less glass and steel, which can greatly reduce the environmental footprint of a build. They complete carbon impact analysis for their builds using the Building Emissions Accounting for Materials (BEAM) tool, designed by Builders for Climate Action. Since they are a smaller affiliate and have a unique model, they have been able to experiment with sustainability, leveraging their community to achieve their goals through innovative approaches rather than traditional green building practices alone.


Gunnison Valley is using local natural resources to their advantage in their builds. They incorporate Colorado’s abundant resources—like lumber, clay, straw, and other biophilic materials—in place of non-sustainable choices. They have found that this resource conscious approach offers many benefits, as plant-based materials sequester carbon and local materials reduce emissions due to less transportation.


In 2019, two Habitat homeowners were interested in a straw bale home, and Gunnison Valley worked with them to create an ecologically sound home. They used materials including straw and cellulose for insulation, around 90% local lumber, and other natural materials like wool, cork, and clay throughout the house. The straw bale hybrid used increased insulation values ranging from R-45 to R-70 for walls. One winter, while unheated, the home remained above 50 degrees inside for over a week, while outside temperatures were an average of -10 degrees, demonstrating the effectiveness of the combination of insulation and solar used for the build. According to the BEAM tool, this home will sequester more carbon than it emits by the time of occupancy, and it is expected that in 30 years of use this house will be carbon neutral. Beyond environmental benefits, the use of local materials was estimated to keep an additional $30,000 in the community.


Part of Gunnison Valley’s success with implementing innovative materials in their builds relies on their local community. They leverage support from local universities and non-profits, including key partnerships with Western Colorado University, the Coldharbour Institute, and Equitable Solar Solutions. Their local building inspector is also very supportive and willing to work with Habitat on out of the box solutions. In addition, the organization itself is changing. Previously, many members of the Board were not active in the building process, but there has been around 50% recent turnover in their Board. This provided an opportunity to work with new people and gain alignment and support for the affiliate’s new direction toward innovative and more sustainable builds.


For more information see: https://www.hfhgunnisonvalley.org/projects/205-south-6th-street




Concrete-Free Foundations


In 2011, Greater Jackson Habitat began to explore how they could build more efficient‑and lower cost- homes for their buyers. Their journey started with energy efficiency. The first change they made was a switch to building all-electric homes, which they have successfully been doing since 2015. Although they were building very energy efficient homes, they had a high carbon footprint most commonly due to the large volume of concrete used in builds. Other decisions made in the build process, such as using air sealing compared to caulking, demonstrate the tradeoffs between lower cost, higher efficiency, and more sustainable homes. However, they have been making progress toward their goal, stepping up their builds every year to make them better.

Greater Jackson highlighted the importance of attending green building summits to generate ideas about new techniques and innovations they can use in their builds. They believe attending and bringing information back to the affiliate is a key way to challenge their team to implement new strategies. In 2015, they went to their board to gain buy-in for some of these new types of builds. Although some cost a bit more, they were better for the environment and homeowners. In addition, they found that local corporations and businesses have interest in being involved in green projects and are willing to provide funding and resources to Habitat builds that include such programs. They are continually working to draw these groups in as bigger partners.


Around 2018, Greater Jackson learned a new method of building foundations using all wood instead of concrete. This technique was in discussion for a while, and 2022 was the first year they tested this process for building two houses on Franklin Street. These foundations use materials including wood, gravel, and cut stone instead of traditional poured concrete, which offers many benefits including lower cost and reduced carbon footprint. To evaluate benefits, Greater Jackson compared two builds of the same size (a 21’ x 35’ footprint) each using a different foundation style. The traditional concrete foundation cost $21,000 including labor and resulted in a carbon footprint of 27 tons of CO2. The all-wood foundation was installed by Habitat volunteers (only cost $15,000 to install) and had a carbon footprint of only 4.1 tons of CO2. The affiliate embraced this foundation style as a great step toward meeting their cost-saving and environmental goals.


“It is much more gratifying than just showing up and having a concrete slab to build on, because right away you are looking at that and if you are looking at it from an environmental standpoint, you just showed up to a huge carbon footprint that is going to be there for 100 years.”

– Greater Jackson affiliate


There are a few challenges with using an all-wood foundation. This approach can’t be used in every state due to climate concerns, although it is suitable for most. Areas with a north, north-central type climate or those with a non-coastal environment could likely employ this strategy. The process is also more time consuming and labor-intensive as it requires the right equipment and volunteers for installation. The prep time took one to two weeks to complete two foundations. One benefit is that once completed, it can be built upon immediately without having to wait for it to settle as with a concrete foundation. For success, it is important to have a volunteer base who is excited about the project and willing to put in extra work for it.


Tiny Homes


Pioneer Valley Habitat’s focus is on building small, simple, and energy efficient homes, where sustainability overlaps with affordability. There is give and take with this approach, as some materials are very affordable but do not have a great environmental impact. However, by focusing on practical implementation and building smaller homes, they can use less of these types of materials and make improvements in other areas. They believe dual benefits is a key aspect of their simple building focus. For example, building a more durable home is both more sustainable and better for Habitat homeowners because they do not need to replace things as often. They also have found that the industry as a whole has changed in recent years, especially in Massachusetts where building and energy codes have become stricter. Initiatives like energy efficiency and HERS ratings have become commonplace as the industry shifts towards embracing some of these ideas.


One of their simple building initiatives is the Big Enough Homes project. This project started being developed in 2017-2018, and the first pilot homes were built in 2019. Their goal was to explore how building small can be a tool for affordability, by implementing simple build designs and processes and reducing the number of materials needed. They use standard construction techniques to keep builds simple, such as traditional wood-framed houses, which may not have as great an environmental savings but are easy for volunteers to assist with without requiring the expertise of highly specialized builds. Instead, they earn their environmental and cost savings from building a smaller footprint.


Traditionally, Pioneer Valley built 2- to 3-bedroom homes, but they realized this missed an entire population of homeowners. Their first 1-bedroom home at 1 Garfield Avenue in Northampton totals 650 sq. ft. and was built on a small lot. Focus was on a simple box-shape design that minimized materials. One challenge was the permits required to build on a small lot. They had to apply for cluster development zoning in addition to a permit for smaller driveway and house setbacks. Using smaller setbacks allows more efficient use of land in existing neighborhoods and also had sustainability benefits. After construction of these houses, Northampton changed zoning laws to allow for smaller developments. This zoning is unfortunately not always allowed in other parts of Massachusetts or in other states but does present an interesting opportunity for Habitat affiliates to get involved with driving change toward smaller development.


One important consideration in these builds is how construction intersects with social aspects, such as homeowner culture, financials, and zoning requirements. When designing homes like this, Pioneer Valley had to balance the size of the build with the wants of the homeowner, for whom the switch from renting to home ownership has important cultural considerations. Homeowners expressed wanting features like a bedroom door and a washer and dryer in-house, which dictated a minimum size that the affiliate could build. However, beyond these features, homeowners were very willing to engage with smaller build options.


“If more people built small, they would see that a small home is all the space they need.”

current owner of 1 Garfield Avenue


Similar to other strategies discussed in this case study, the community is an important aspect of the success of these builds. Pioneer Valley stressed the importance of considering the house as a whole system. Rather than just implementing a green initiative, it is important to understand how that feature impacts other areas of the build, including design and livability of the home. Because of this, it is important to have a diverse range of stakeholders involved in green building projects—from architects that help with design of buildings, to home energy raters that provide a critical third-party review of a home, to volunteers who are passionate and willing to help reach your vision. There are also many established green building principles that affiliates can use as a starting point to enter the green building space, and then work toward adding more innovative building approaches to their repertoire through the support of their community.


For more information see: https://www.pvhabitat.org/big-enough/


Mixed- Income Development


Habitat for Humanity of Orange County has been working on their green building program for the past two decades. One of the challenges they face is balancing products that are good to make with those that are good to maintain. Some environmental products are not easy for volunteers to work with, which is a challenge they are facing especially for siding. Luckily though, the local community supports implementation of green building strategies. They have a large volunteer base, being close to universities, and many volunteers ask about sustainable practices, even something simple like where the recycling bin is. Volunteers can get turned off from returning if they do not see these initiatives in practice. In addition, asking about green building strategies is included when they apply for permits or developments in the area.


Another challenge faced in North Carolina is that people want to live in highly desirable areas, like Hillsboro and Chapel Hill, but there is limited land available for new development. Donors and town governments have been pushing builders toward denser developments. Orange County has decided to enter this space with their newest development, Weaver’s Grove, which will be the largest development contract for this affiliate.


Construction on 32-acres will hopefully begin Spring of 2023 and continue over the next five years. It will feature 101 Habitat homes, in townhouse or duplex styles, for a total of 237 units. Additionally, they are selling 40 single family lots and three condo buildings totaling 96 units to two local builders to help raise funds for this project and create a mixed-income development.


Orange County has sometimes considered different types of construction too expensive or not in line with a traditional Habitat build. However, you can usually find a way to do sustainable approaches affordably, and they are beneficial and fit well with the Habitat mission. One recent project example was implementing permeable pavers to reduce stormwater runoff from impervious surfaces. There are often grants available for innovative solutions like these, with interest in funding pilot programs that feature sustainable practices.

For more information see: https://weaversgrove.org/


Conclusions