Is a raft slab more expensive than a waffle slab?

There’s no fixed answer — cost comparison between raft and waffle slabs depends heavily on your specific site’s soil classification and size, not a general rule that one is always cheaper.

Where soil conditions genuinely suit a raft slab, it can be more cost-effective, since it’s a comparatively simpler single-pour system. But if your soil is reactive and needs a waffle slab’s specific design to perform properly, comparing the two on price isn’t really meaningful — a raft slab wouldn’t be an appropriate, compliant option for that site in the first place.

The genuinely useful comparison is against what your soil report and engineer actually recommend for your site, not a generic price-per-square-metre figure pulled from an unrelated project.

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