Laying new patio over existing slabs

[abiknox]

I curently have a concrete slab patio 3m x 4m that i want to re do with nicer slabs. The current slabs are bedded down in 3 foot of concrete and so pulling them up is out of the question.

Can anyone tell me what preparation i would need to do first, can i just put a layer of sand over the top and lay them over? If so what thickness and what sand? I could also do with knowing the ratio and sand needed for the correct cement mix if anyone can help?

I have checked the height tollerance and this is fine.

Thanks in advance!

[landscaper2]

3ft, that's a mighty base!!!

If the existing slabs come up easily, it would be better to take them up first and clean up the base, a patio is only as good as the base its laid on and a sandwich of unstable slabs would not be good.

If they are really sound however, then pave over them. I would use a mortar mix of 5 parts pit(building) sand and 1 part cement at about 25mm depth as long as the base is even. Point the slabs with 3/1 mix soft sand/cement.
At 25mm bed you will need roughly 0.4cu mtrs of sand.

[AlBags]

Usually will lift ok.
Nuclear Fallout bunker? 3ft concrete .. lol

[ChuckFickens]

Wow!

I looked at this earlier (didn't know the answer, and still don't...) and read it as 3 inches for some reason! (probably because it's what I expected it to say)

Sorry I can't help, but please tell us...... why 3 foot of concrete?? there has to be a reason.

[AlBags]

It's the bodies, you see ... underneath.

[ChuckFickens]

Well unless the property is built on a hell of a slope.... yeah that's what I thought :)

[ladybirder]

Oh dear:-(

[AlBags]

They smell .. unless you can get at least a couple of feet of green concrete over them.

[abiknox]

Thanks for the answers! I really have no idea why there is so much concrete, we were just about to start digging up the slabs when our next door neighbour poked her head over the fence and stated that we would be wasting our time becasue there is 3 feet of concrete under them! She said she was with the previous house owner when he was doing the garden and he wanted to do it properly!

Who knows hey! Ill be keeping my sences open for the smell of decay though! :)

[AlBags]

Fred West's :-/

Brookside .. remember?!

[landscaper2]

..........I'd like to amend my advice given above. Break out the concrete..............we all want to know what's underneath!!!