A Guide to Healthy ADU Materials

Insights
Written By Workbench Studio
 

We want everyone to live in a healthy home. A healthy home provides good indoor air quality (IAQ) through the types of interior materials chosen and how the interior spaces are ventilated.

Here are some suggestions for materials for your ADU that are low-emitting materials that do not release significant pollutants and support a healthy indoor environment. Note that often the least expensive material can have negative long-term health impacts, so please consider this when budget planning and selecting products for your ADU. Additional tips can be found from sources such as the U.S. Department of Housing and Urban Development.

Lower the VOCs

As a general starting point, the goal is to evaluate and select Select materials with low to zero volatile organic compounds or VOCs. VOCs  are chemicals found in common products and building materials that can escape into the air and cause illness and allergic reactions.

Flooring

Cork or natural linoleum

Consider a rapidly renewable resource such as cork or natural linoleum for flooring. Both options are easy to clean, resilient to spills, soft on the feet and come in many colors and patterns. 

Wood flooring

Consider solid wood or ‘Prefinished Engineered Wood’ which has a layer of natural wood over a substrate that makes it more 'stable' (little to no warping) and uses less wood. There are also wood flooring products that come from salvaged wood sources or are Forest Stewardship Council (FSC) certified. FSC wood is guaranteed to be harvested from responsibly managed, environmentally conscious forests. 

Tile

Tile, especially with recycled content, is durable, environmentally friendly, and comes in many styles. 

Textiles

Consider area rugs that can be easily cleaned. Area rugs made with wool, jute, or other natural materials do not ‘off gas’ and are healthier options than synthetic ones.

Walk off mats

Prevent unwanted dust and debris from entering the home by having a good mat before the entry. 

Walls and Ceilings

Most paint manufactures offer low-to-zero VOCs versions of paint. Avoid oil-based paints. Note that darker paints typically have more VOCs than lighter colors. When painting, be sure to keep windows open with as much ventilation as possible. Gypsum board (a.k.a. drywall or sheetrock) with recycled content is also available, which uses less raw materials during its production. Be sure to keep gypsum board dry and protected from the elements before and during installation. When installed, wet or damp construction materials (such as gypsum board) can grow mold and compromise the indoor air quality. See point 6 for information regarding a healthier approach to sealants.

Wall Tile

Search for a tile with recycled content, glass, terracotta or salvaged tile from a local resource to cut down on costs and your carbon footprint. In Northern California there are sources for locally made tile which can cut down on transportation costs and greenhouse gas emissions. Make sure your contractor uses a zero-VOC thin set and sealer. Coordinate with your contractor to source a non-toxic/no VOC waterproof membrane. These are important to include behind tiles in wet areas to provide waterproofing behind the tile and prevent the growth of mold.

Countertops

Select a countertop that is made of recycled content, such as recycled glass or granite chips. Another option is to find a natural stone slab that is mined locally, within 500 miles or less from your home/project site. Counters are also available at local salvage yards or at a local Habitat for Humanity ReStore. For a less traditional option, consider wood, which is a rapidly renewal resource. Butcherblock counters are a nice choice and bring warmth to the interior. There are also products that use a combination of resin and paper (either recycled or from responsibly managed forests) to make strong and easy to clean surfaces. These options promote a healthy indoor environment as they do not off-gas. Check with manufacturers and suppliers for their sustainability credentials.

Doors and cabinetry

If possible, avoid cabinets and doors with a particleboard core as they can contain formaldehyde, a chemical used in bonding the wood particles. Cabinets with plywood cores or medium density fiberboard (MDF) that use a bio-based resin to bind the layers are better than other forms of formaldehyde. There is even “wheat board” which uses agricultural waste as a core. When finishing your cabinet and door surfaces, follow the guide on paints under point 2 above. In terms of sustainability and healthy decisions for the environment, try to reuse materials whenever you can, avoid old-growth timber completely, and use FSC wood wherever possible.

Adhesives and Sealants

Adhesives and sealants may be overlooked when it comes to specifying products with low to zero VOC content. These products are often applied “wet” and often have a higher VOC than other, more stable products. Guides are available on the internet which can be helpful to consider when purchasing adhesives.

Maintenance

Most cleaning products contain chemicals associated with eye, skin, respiratory irritation, or other human health issues. Additionally, the concentrated forms of some commercial cleaning products are classified as hazardous, creating potential handling, storage, and disposal issues for users. Using “green” cleaning products can help to reduce the human health and environmental concerns that come with cleaning. It is a good idea to avoid products with strong scents, even if good smelling, as they often contain unsafe chemicals. Look for labels such as the EPA SaferChoice or Greenseal. Avoid anti-microbials whenever possible. You can even make your own cleaning products, which also can reduce costs and can cut down on plastic packaging. The internet offers many options for DIY cleaning products. 

Summary

If it is not clear whether the products being specified for your home contain harmful chemicals, ask your contractor to provide data sheets for review, or ask the store from which you are purchasing them to provide more information. There are also many resources on the internet that you can research when it comes to selecting interior finishes for your ADU. For example, The Living Building Challenge Redlist is one source. 

Beyond finishes, healthy homes also include good views to the outdoors, natural light, and access to clean water all of which are a part of creating a healthy interior environment. If you have questions or are looking for more help in designing interior spaces, selecting materials or building an ADU please reach out. We’re dedicated experts in creating housing in California and would be glad to help.

 
 
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