Is a raft slab suitable for a granny flat?

Often yes — a granny flat’s typically smaller footprint and lighter loads compared to a full house can suit a raft slab well, provided your site’s soil conditions are genuinely appropriate for this system.

Like any habitable structure, a granny flat needs the same genuine soil assessment and engineering process as your main home — its smaller size doesn’t exempt it from proper foundation design.

Your engineer determines the most appropriate foundation system for your specific granny flat based on your soil report, the same rigorous process used for any residential structure, regardless of its smaller scale.

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