A Mytikas cabin has a Class A fire-rated exterior envelope. Five things make it so, and each one is standard on every cabin we build.
In the film above, Ed Libby and Nathan Fisk walk through the siding, the foam and the steel behind them.
The five parts
- James Hardie fiber cement siding. We use James Hardie HZ5, rated to 2,200°F.
- A fire-rated insulated panel between the siding and the steel.
- An all-steel structure that won't burn. The structure has no wood framing.
- A standing seam steel roof, closed, with no soffits for embers to enter.
- TimberTech decking with a Class A fire rating.
Why the envelope is the point
Wind-driven embers are one of the main ways a wildfire reaches a building. They look for a way in, or for something to light. A wood frame behind vinyl siding gives a wildfire fuel and a way in. Ours is built to give it neither.
That is why we talk about the whole envelope and not one material. Siding alone does not make a fire-rated exterior. The panel behind it, the roof above it, the deck beside it and the structure inside it all have to do their part.
What Class A does not mean
It does not mean a cabin cannot be damaged by fire, and we will never tell you it does. Class A is a rating of how the exterior performs under fire exposure. Fire, like flood and hail, is an outside event, and insurance is the right protection for it. We recommend insuring the cabin for its full replacement value from the day you get the keys.
Where a jurisdiction requires fire sprinklers, they are available and quoted per project.
Questions we hear
Is the siding real fiber cement? Yes. James Hardie HZ5, over a fire-rated insulated panel.
Why no soffits? Open soffits and vents are a common path for embers into a roof. Ours is closed.
Is the deck fire-rated too? Yes. The included TimberTech decking carries a Class A fire rating.
Does steel framing help in a fire? The structure is steel, which won't burn, so the frame is not fuel.