A raft foundation was required on the beach shingle, and to avoid cold bridging a continuous slab of insulation with integral upstands (kerbs) was created using Foamglas. The Foamglas is impervious to contaminants but most critically, water which could be useful in this Flood Zone 3 location. 2 layers of 150mm Foamglas T4+ boards (300mm overall) achieves a U value of 0.11 W/m2K which will be worthwhile over a perhaps 150 year life. Foamglas is an expensive option but it’s long term resistance to pretty much everything means it is less likely to fail and should last at least as long as the building. The kerbs are the formwork creating a tray in which to pour the slab, a very simple solution, much like the Isoquick system used on a previous project.
