Hardcore schmardcore - Suitable sub-base

[Der Kaiser]

Hi All,
I'm looking for some guidance if possible?

I'm laying a small patio area at the back of the garden ~3.5m by 2.5m. This is currently a soil base and on reading guides it sounds as though I need to purchase about a ton of screeding or DTp1 and hire a plate compactor to make a base of ~75-80mm.

I currently have some pieces of old broken paving, how wrong would it be to lay this and fill in with sand ballast and compacting creating a sort of crazy paving hardcore before then laying a dry bed of sand/cement mix and my new paving.

I realise it would be a 'comprimise' I'm just wondering by how much??

Thanks for any help?

[lutonlagerlout]

well although not recommended bill (can i call you bill,kaiser?) it should be ok for foot traffic
i recently did my patio at home and had 150mm to make up,i had about a tonne of random yorkstone and bits and bobs so i laid this in first to 100MM depth then added 50mm of mot and wacked the lot for 45 minutes
i am fairly confident that it will out last me anyway
cheers LLL

[Tony McC]

I think you'll end up with differential settlement and uneven levels on the completed paving. It'll take a few years to show, but because some areas of "sub-base" (and I use the term in it's loosest possible definition) will be solid and some will be loose, you'll get more settlement in some spots than in others.

Of course, it won't be the end of the world, especially as this is just a patio, but I'm a firm believer in "if a job's worth doing..." and for such a small job, there's almost no cost saving involved. If you were to break up the hardcore into pieces no bigger than 50mm, and then mix that with granular material (Type 1, 804, C/run), then there'd be less risk of diff settlement, and you'd have ridded yourself of all that old paving in the process.