Deck footings

4 Apr 2021
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United Kingdom
New to the forum although I have got a lot of useful stuff from it over the years.

I am in the process of landscaping my new build and I am about to deck the large (20m x 5m) area at the rear of the house.

My original plan was to patio it and I now have 300mm of compacted hardcore over the entire area.

I have seen conflicting advice on fitting deck posts (either to 400mm or 600mm) set in concrete whilst others suggest I could get away with a floating deck.

Will compacted hardcore be sufficient to support the deck without worrying about frost movement etc or should I start digging.

I must admit having just finished fencing the place I don't fancy digging out another 60 odd post holes if I can avoid it.
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Hardcore may move unevenly over time, or sink directly under each joist, and timber is better off not laid directly on surface to avoid it being constantly damp.

Consider a dense concrete block as a pad with the joist spanned between, and some DPC between it and the timber.
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