Self-Builders Knowledge Centre
Everything you need to know about insulated raft foundations for your self-build project — from first principles to getting a quote.
Guided journey: 5 essential steps
FAQs for Self-Builders
What is an insulated raft foundation?
An insulated raft foundation is a reinforced concrete slab that sits on top of a layer of load-bearing insulation,...
Why Use an Insulated Raft Instead of a Traditional Raft with Insulation Above?
Insulation below the slab does more work, with less effort. When insulation sits above a concrete raft, the concrete...
What Is the Minimum Concrete Thickness for an Insulated Raft Foundation?
200mm for most houses. 250mm for taller buildings. If a supplier is showing you anything less, ask them to explain...