Insulated concrete forms (ICF) are a material to consider when building a mold free home. The main components are concrete and foam, with some plastic connectors. None of these have organic materials that support mold growth.
Brands include Fox Block and Nudura. In terms of which brand might be better, the composition of the materials in each brand is similar. Both use Expanded Polystyrene (EPS), a foam used for for insulation and the forms that hold the concrete in place.
The recycled polypropylene mentioned is used in plastic parts: webs, hinges, fastens, and so forth. Plastic can’t grow mold. And the polypropylene is not a potential air quality issue.
A potential air quality issue is from the styrene. Ingredients on the safety data sheets include styrene and pentanes. Pentanes are from the blowing agents used to make the foam. These may off-gas by leaking through the foam after it’s blown. There is the potential for some pentane to end up in the air. In air samples I’ve collected (for VOCs, known as volatile organic compounds) in homes which where built, I don’t recall detecting pentanes so much as the styrene.
The as-built effect on air quality is minimal if a ventilator system (Heat Recovery Ventilator or Energy Recovery Ventilator) is installed.
According to the specs for Fox Block and Nudura, when tested for mold, the result was “no growth.” This is as expected for clean (new) materials that don’t support mold growth. However, left exposed to the elements, surfaces will collect dirt and debris from nature that do support mold growth. The surface of the finished forms must be protected from the elements to prevent a bio-film of growth.
When building with insulated concrete forms, the installation and proper flashing of the windows is more technical than a stick-frame (wood framed) home. If optimal window flashing details are not added to the building specifications, water may end up in the interior of the blocks after the home is built. While this might not cause mold growth, it allows for bacteria and other organisms to flourish. This might result in musty odors and a potentially unhealthy construction.
To flash and install windows properly requires a 4-way consultation with the builder, ICF installer, and the window installer. Each party needs to understand the details and what’s expected of them and how they need to work together to coordinate this. It’s best if this conversation happens before materials arrive. If you wait until the windows are being installed, the contractor may not allow work to be stopped as parties agree upon the best installation methods and flashing details.
Building with insulated concrete forms is a good material in regard to using materials that don’t support mold growth. Building with ICFs, it’s more technical to properly flash and install windows. To learn more, contact us. Need help taking to your builder? Let’s talk.
