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LEED for Homes 101: Materials & Resources
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.
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How Do I Choose Sustainable Materials for My Home?
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.
What Materials are Considered by LEED to be "Environmentally Friendly"?
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:
- At least 25% reclaimed materials (includes salvaged, refurbished, or reused),
- At least 25% post-consumer of 50% pre-consumer recycled content,
- For concrete, at least 30% of fly ash or slag used as a cement substitute and 50% recycled content OR 90% reclaimed aggregate or recycled content,
- Wood that is FSC certified (note this is a prerequisite for tropical wood)
- Bio-based materials that meet the Sustainable Agriculture Network's Sustainable Agriculture Standard, or
- Products purchased from a manufacturer that participates in an extended producer responsibility program (see this explanation from the State of California).
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.
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.
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:
- That water should flow away (not towards) the home through sloped patios/decks/driveways.
- Making sure there is flashing around all windows and doors.
- That drain tile is installed around the basement and crawlspace walls.
- A requirement that wall-to-wall carpeting not be installed within 2 ½ feet of showers, tubs, or toilets.
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.
Melissa Rappaport Schifman
Melissa became the Twin Cities’ fifth LEED for Homes Accredited Professional (LEED AP) and completed the work necessary to get her own home LEED Gold Certified, the basis for her book, Building a Sustainable Home: Practical Green Design Choices for Your Health, Wealth, and Soul, (Skyhorse Publishing, August, 2018). With her corporate experience in finance, marketing, and business development, and an MBA and Master’s in Public Policy from the University of Chicago, Melissa has been providing sustainability advisory services to businesses, governmental agencies and non-profits, focusing on strategic and operational change that provide bottom-line financial returns. She has led the LEED certification of two million square feet of commercial buildings, written GRI-compliant Corporate Sustainability Reports, is a LEED Pro Reviewer and LEED mentor with the U.S. Green Building Council. She is the founder of Green Intention LLC where she writes about sustainable home living.
