Two weeks to a shell: building with SIP panels
Months of digging and concrete. Then the chalet itself went up in under two weeks.
By Marc 3 min read
A chalet emerges
For months, the chalet was a hole in the hillside, then a concrete box. Then the panels arrived, and in under two weeks it was a chalet.
That’s the strange rhythm of a SIP build. Almost all the work happens before anything goes up on site. The panels are designed on computer from the architect’s plans, cut in a factory in the UK, numbered, and shipped out ready to slot together. By the time they reach Saint-Gervais, the hard thinking is done.
Getting the panels up the mountain
Factory-made panels have to travel, and ours had a long way to go: from the UK, across France, and up a narrow lane to the plot. Kingspan TEK panels can be up to about 7.5 metres long, so delivery needed planning. With the narrow access lanes, the panels were removed from the articulated lorry away from the site, then transported in sections for the last mile.
Once on site, a crane lifted each panel into place. Cranes are in high demand in the area so it was good that we’d arranged for the crane to remain on site throughout this phase of the build.
A base that’s dead level
Panels made to the millimetre need something just as accurate to sit on. That’s why the last job of the groundworks was finishing the tops of the concrete walls perfectly level. Any error there would have carried all the way up to the roof.
The first walls
The panels started where the concrete stopped. Our ground floor is concrete, set into the slope, so the first SIP walls went up on top of it, forming the floor above.
Each Kingspan TEK panel is a sandwich: a rigid urethane insulation core between two sheets of OSB, a tough engineered board. The panels have recessed edges, and they lock together with splines: strips that sit in the recess between neighbouring panels, fixed through the boards on each side. The joints are sealed with expanding foam, so the wall ends up as one continuous, airtight skin rather than a row of separate pieces.
That’s where the warmth comes from. No gaps, no cold spots, and very little for an Alpine wind to find.
Two weeks later
In under two weeks the shell was up, the shape of the chalet finally standing on the hillside. After months of planning, digging and pouring concrete, watching it happen that fast was one of the most satisfying moments of the whole project.
A little context
How long does it take to put up a SIP chalet?
The panel shell can go up very quickly: ours took under two weeks. The whole build takes much longer once you add the groundworks before and the cladding, roofing and fit-out after.
What are Kingspan TEK panels made of?
A rigid urethane insulation core sandwiched between two layers of OSB board. They come in 142 mm and 172 mm thicknesses, and are made to your plans in a UK factory.
How do SIP panels join together?
The panels have recessed edges that take a spline between neighbouring panels, fixed through the boards and sealed with expanding foam. The result is an airtight wall with very few cold spots.
Why does a SIP chalet need a very level base?
The panels are factory-cut to tight tolerances, so any error in the base carries up through the building. Our concrete walls were finished dead level before the panels arrived.
Can you build a SIP chalet on a steep site?
Yes, but the panels have to reach the plot and be lifted into place. On a steep, narrow mountain lane, delivery and lifting need planning before the panels are even made.
