Knowledge Centre / What Is an Insulated Raft? / What is an insulated raft foundation?

What is an insulated raft foundation?

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An insulated raft foundation is a reinforced concrete slab that sits on top of a layer of load-bearing insulation, with more insulation wrapped around its edges. It supports the building structurally and keeps heat from escaping through the floor — no cold bridges, no heat leaking into the ground, and no separate ground floor slab to worry about.

House section showing ISOQUICK continuous insulation beneath the floor slab and around the building envelope
ISOQUICK® forms a continuous insulated foundation beneath the floor slab and external walls.

How Does an Insulated Raft Foundation Work? Think of an insulated raft as a warm island sitting on the ground. The concrete slab spreads the weight of your building across the insulation beneath it, and because the insulation is load-bearing (tested and rated for exactly this purpose), the whole structure remains solid and stable over the lifetime of the building. Because the concrete acts as both foundation and ground floor, you eliminate an entire stage of the traditional build process....

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