Waterproofing a patio?

[Nosher]

Hi all, I'm a newbee on this site so might as well start by bending a few ears.

I'm an expat from London I live in sunny Cyprus although not sunny all year round. And when it rains, it rains, unlike anything I ever saw in the UK.

The point is that I have a grey slate patio at one end of the pool under which is my workshop. When it rains I get water leaking down the wall onto the electrics which is never a good idea but is lost on these guys.
The builders (Ha!!) didn't install a damp proof membrane when they laid the patio so I now have to dig it up and find some way of making the whole thing waterproof. I do not want to disturb the coping stones to the pool but can dig down past them to a depth of about 10cms. Ideally I would like to buy something that can be poured onto the ground and find it's own level and waterproof everything it touches before re laying the crazy paving. The area to be done is about 2m x 10m.
One idea I'm toying with is to grind a groove at the bottom of the coping stones and insert some kind of roofing felt then seal it with a torch. Not sure if this is the best way but am hoping you guys may advise.

Many thanks in advance,

Nosher

 

[Deluks]

You don't need a waterproof patio, you need a flat roof. Search on here in the roofing section for flat roof options and ideas. Alternatively put a roof up inside the workshop and drain the water out somehow.

You might be looking at a good quality pond liner laid sandwiched between thin protective layers such as polystrene.

 

[Nosher]

Thanks for that Deluks.

I can't erect an internal roof as such because the water runs down the wall onto the electricity box.
The idea of a pond liner on the outside has definite possibilities though.
I need to remove the crazy paving and substrarte and waterproof from there. Had thought of applying a load of self leveling waterproof compound; something that will penetrate the cracks into the fabric of the building and then using your suggestion of the pond liner to prevent anything going further. Just have to think of a way to fix the liner to the coping stones and so far am considering some kind of mastic before relaying the paving.

Nosher