Which sub base

18 Feb 2006
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United Kingdom
Hi all

Going to be digging out for a new patio soon once my new retaining wall has been finished for a new patio. We are on clay soil and planning on digging 8” down from 150mm below dpc (current patio too high) for 5-6” hardcore and then, 2” laying bed and 1” natural sandstone flags. Is 6” too much?

As a balance what’s the mast cost effective sub base to use. I don’t mind using type 1 if that’s the best, but if there’s something cheaper that’s just as good I’m open to suggestions, bearing in mind I’ll need approx 35-40 tonnes of it

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If you get your type 1, 20ton at a time it’s much cheaper.
Yeah I’ve found 20T a lot cheaper. Someone even mentioned tarmac plannings

What thickness should sub base be, getting conflicting advice. 3-4” for flags?
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We had 12t of recycled concrete to use first, and it went down great and had more dust and was about £11 or £14 a tonne. Needed spraying after it went down to limit dust coming from it.
Next load was proper limestone type 1 at a cost of nearly 3 times as much. The proper stuff just seemed to go down better, and certainly whacked down a lot better.

We ended up going down about 12” in some parts due to clay, and wet ground.

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