Last Updated: Jul 1, 2021
Welcome to the fifth category of the crazy LEED for Homes rating system! In our series of articles, and as outlined in our LEED for Homes 101 overview, we translate a technical reference guide into comprehensible language for homeowners, home builders, and residential architects. Why? Because while a tiny percent of homeowners will ever go through LEED certification, the rating system lays out best practices to making homes healthier, efficient, and better for the planet. We think that's a good thing; that it's knowledge worth spreading.
This section refers to the myriad of decisions we make around flooring, countertops, cabinetry, and roofing. Also, it addresses the seemingly minor decisions that homeowners might not weigh in on, like framing, drywall, sheathing, and insulation. The Materials and Resources category has two prerequisites and is worth up to 15 points.
Arguably the most compelling section of LEED for Homes, the Materials and Resources section delves into three sustainability topics:
There is no such thing as a purely sustainable material for material selection—it is merely more or less sustainable than the conventional alternative. There are many different sustainability criteria, and it is up to you to decide what you value most. For example, some more durable materials will last longer, so you won't have to replace them, but that could be offset because it takes a lot of energy to produce (referred to as embedded energy). Every selection involves weighing the tradeoffs, and LEED helps us understand what is most important from a sustainability perspective.
LEED does not provide a bulleted list of what you should purchase for your home. Still, it does tell you one thing you cannot buy: tropical wood that is not certified by the Forest Stewardship Council (FSC) or USGBC-approved equivalent. (See this Rise article to learn more about wood certifications.)
"Tropical wood" is defined as any tree species that grows between the Tropic of Cancer and the Tropic of Capricorn. This region includes Central America, Brazil, Southeast Asia, Central and Western Africa. Many of these wood varieties, like mahogany and teak, are coveted for their durability and beauty. But in practice, harvesting these types of trees has caused deforestation, loss of habitat and biodiversity, issues with soil fertility, and contributes to climate change.
So, the LEED rating system requires that if you want tropical wood in your home, it must be certified by an independent third party that it was grown and harvested responsibly. A better choice is to avoid tropical wood altogether. There are ample beautiful wood choices grown sustainably in North America—like fir, cherry, pine, maple, and oak.
To earn points in this section, you have to pay attention to where the materials are made and how they are made. For items such as aggregate for concrete and foundation, framing, and drywall or interior sheathing, you can earn up to one point each. To achieve these points, at least 50% of the building component must be "extracted, processed, and manufactured" within 100 miles (160km) of your house. This "local" sourcing cuts down on transportation and the associated carbon emissions; it also helps the local economy. The lesson? Ask your builder or contractor where they source the materials. (The good news is that anything reused from the site automatically meets the local criteria for renovations.)
You can alternatively earn up to five points for how the material is made. It's a little more complicated (see table below, directly from the LEED Credit language), but basically, look for materials that are compliant—meaning they contain or are labeled as:
These criteria apply to all building materials except HVAC and pipe insulation. So, when you're choosing flooring, doors, cabinetry, decking, even trim, etc., find out how it's made. Richlite, for example, is an excellent countertop material made of recycled paper and is extremely durable. Great options abound; sometimes, you only need to ask.
Hopefully, these criteria help reduce the number of purchasing choices. But LEED is missing one key component: material omission. (After all, isn't the greenest material is no material?) Why doesn't LEED give points to homeowners who choose to leave some of their ductwork and piping exposed, forgoing things like drywall, paint, and wallpaper? Leaving a concrete floor uncovered and polished can be a beautiful alternative to flooring; homeowners can save resources and money. Another creative idea: no drawer pulls. If a cabinetmaker is making custom cabinetry, have them cut out a little hole to pull it open. (It will save your thighs from getting bruised on those drawer pulls as well!)
Moving on from purchasing, at the other end of a material's life cycle is waste. LEED projects can earn up to one point for recycling or salvaging 50% or more construction and demolition materials; projects can earn two points for diverting 75% or more from the landfill.
LEED Residential v4.1 has become more stringent than earlier versions of LEED for Homes, and the calculations have become relatively complicated. (See the LEED credit language for more detail.) Construction companies used to get away with providing basic paper reports that showed an overall percent diverted. In this updated version, the facility where the material is recycled must be certified by the Recycling Certification Institute (or approved equivalent). In the US, you can find a certified facility here. In reality, most home construction and renovation projects will not be LEED-certified. So, the takeaway is to make sure your construction waste company recycles its waste.
The second LEED credit that addresses waste reduction is called "Material-Efficient Framing." The idea here is to use advanced framing techniques to reduce the use of unnecessary framing materials. If you have hired a contractor to build or renovate your house and aren't familiar with standard framing, this can be a way to reduce your overall footprint and save money.
Durability is the third component of the Material & Resources category. A home that lasts longer is more sustainable because it will need fewer materials replaced over the life of the house. But this section is not really about the hardness of a floor or countertops that won't wear down—it's about making sure your home does not suffer from water damage.
There is one prerequisite under "Durability Management" with two parts: first, meet the ENERGY STAR for Homes, Version 3, Water Management System Builder Requirements. This comprehensive list includes:
The second part requires installing indoor moisture control measures such as water-resistant flooring in the kitchen, bathroom, entryway, and laundry areas. That means that for those high-use areas likely to get wet, don't install carpet or flooring materials that would absorb water, like cork. This prerequisite is full of small but essential details to keep your home free of mold and rot; see the credit language for a complete list.
After the prerequisite, a project can earn one point by inspecting and verifying that the prerequisite, as outlined above, was met. A project can earn another point by ensuring that each exterior door is protected by an overhang or awning. This feature must extend at least two feet beyond the outer wall, and the width should extend at least one foot past the exterior door. (This is also very helpful for package delivery and visitors waiting at the door in the rain!)
The third and final point addresses moisture control: wrap insulation around all cold water pipes in unconditioned spaces to reduce unwanted condensation and drips.
With the hundreds of material choices homeowners make, even for a minor remodel, referring to this LEED section for best practices can help you have a more durable home that reduces resources and is easier on our planet. While it may seem overwhelming, focus on the big choices like flooring, cabinetry, and countertops. Ask your contractor to make sure your waste gets recycled. And follow the durability management checklists!