Steel and EPS do not feed mold, do not off-gas and contain no carcinogens or allergens. What that means for indoor air, and why ventilation still matters.
People with allergies, asthma or young children often ask what a house is made of before they ask what it costs. For a steel panel house the answer is short: galvanised steel and EPS foam, and neither one feeds mold.
Mold needs food, water and time
Mold grows on organic material that stays damp. In a wood-framed wall that means framing, sheathing and paper facings, often hidden where nobody sees it until it is serious. Steel and EPS are not food. The panels resist mold, mildew and black mold, and neither material rots or delaminates when it gets wet.
Wet during construction
New England weather does not wait for the roof. With panels there is nothing in the assembly that has to dry out before it is closed in, so a wet week during the build does not become a mold problem behind the drywall later.
No off-gassing
The panels do not off-gas and are allergy friendly. They contain no carcinogens, pathogens or allergens, which matters most for the people who spend the longest hours breathing indoor air: children asleep through long winter nights.
Airtight means ventilate
A well-built panel shell is very airtight. ThermaSteel homes have a track record of extremely low air infiltration on blower door tests, which is exactly what saves the energy. The flip side is that fresh air has to be planned rather than leaked in. Every tight house needs mechanical ventilation designed with the heating system, and your mechanical designer should size it early. We explain the air sealing side in air sealing a panel shell.
How it feels to live in
Quieter and more even. There are no cold walls and no draught at the base of a stud bay, and rooms stay within a degree or two of each other. Warm, dry wall surfaces are also less likely to collect condensation, which is where a lot of household mold starts.
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EPS smoke and flame spread data and the other material reports are on our resources page, with no form to fill in.
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Keep reading
Air sealing a panel shell: joints, tracks and what the blower door reads
The field of the wall takes care of itself. Every number you care about comes from the joints.
Carpenter ants, termites and mice: why a steel panel wall offers nothing to eat
Carpenter ants are a New England problem. Why steel and EPS panels give ants, termites, bees and rodents nothing to eat, and cut the need for pest poisons.
Building on the New England coast: wind, salt air and moisture
Hurricane panels tested to 185 mph including flying debris, and nothing in the wall to rot. What steel SIPs mean on the Maine, Cape Cod and Rhode Island coast.
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