Can screw piles be combined with a waffle slab on the same site?

Genuinely uncommon as a direct pairing — screw piles typically support suspended structures like decks and additions, while a waffle slab is itself a ground-supported foundation system, so they usually solve different problems on the same site rather than combining on one structure.

It’s entirely normal, though, for a single property to use both — a waffle slab under the house and screw piles under a separate deck or extension — each specified where it genuinely suits that part of the site.

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