28/05/2026
Steel frames are not going away. We know that. The industry is built around them, the supply chain is optimised for them, and the price point makes them hard to argue against at the volume end of the market.
We still think there are better ways to build. But if you are going to use steel, at least do it properly. Because the way most steel-framed homes are being built right now is not good enough and the people living in them are paying for it every winter.
So here is what properly actually looks like.
Ditch the thermal break strip. It does not move the performance number in any meaningful way and it gives everyone involved a false sense of progress. It is a sticker on a problem that needs a proper fix.
Insulate externally. A continuous layer of insulation on the outside of the frame is the only approach that actually works. It keeps the steel warm, eliminates the thermal bridge, and gets you to a performance number worth having.
Now a word on materials. You can use XPS for that external layer and it will perform thermally. But here is what you need to understand. XPS is essentially vapour impermeable. Once it is on the outside of your frame, moisture cannot move outward through the wall. The wall cannot dry to the outside. That is fine if you are managing internal moisture deliberately. It is a problem if you are not.
Which brings us to the thing nobody mentions at the point of specification. The moment you wrap your building in continuous external insulation and tighten the envelope properly, you have created a wall that cannot breathe outward. Your building is now dependent on controlled ventilation to manage every gram of moisture your family produces - from cooking, from showers, from breathing, from existing.
That means mechanical ventilation is no longer optional. Not a rangehood and a bathroom fan. A properly designed system that brings fresh filtered air in, exhausts stale air out, and recovers the heat before it leaves. Without it, that moisture has nowhere to go except into your wall cavity. And you already know what happens there.
Build it right or do not build it at all.