Which sub base

[b21playa]

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

thanks

 

[Ian H]

If you get your type 1, 20ton at a time it’s much cheaper.

 

[b21playa]

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?

 

[Ian H]

That’s plenty if it’s on decent ground.

 

[b21playa]

Is it worth getting the recycled stuff? Difference of about £115 a full 20T load

 

[Ian H]

Yes, should be decent enough

 

[b21playa]

Yes, should be decent enough

Perfect. hopefully my local supplier can get it to me in time. Need to fill up my steps as well as won’t be laying patio until next year, after other external works

 

[britishboy7]

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.