Paving over concrete

[MadAlicesDad]

I want to pave our driveway (either slabs or block paving). Currently it is concrete but badly cracked in places, and if possible, I don't want to remove it (cost / effort) and it is a stable base.
The drive runs between two house walls (ours and neighbours).
I will put a drainage channel along one wall and slope the surface towards it, but if I use blocks, will I have a problem with water getting through the gaps and not being able to soak away?
Mike

 

[^woody^]

You'll need to use cement mix for the base not just sand, and deal with the increased height compared to adjacent ground and house DPC level

 

[MadAlicesDad]

They are Victorian houses with 18" solid stone walls and no DPC, and the drainage channel will be below the airbricks. My concern is about water between and under the paving, or are you saying that a cement mix will prevent this being a problem?

Mike

 

[^woody^]

Water would be a problem for a sand base, but not for a rigid base.

 

[MadAlicesDad]

Excellent, just what I was hoping for! Many thanks.
Mike

 

[MadAlicesDad]

I've now done the drainage channels along the house wall, and would like to do this surface with Indian sandstone; it is too narrow to get a car down so is effectively a patio. However are Indian sandstone flags laid on a full mortar base over concrete ok for parking a car on?

TIA
Mike

 

[r896neo]

Large flags will never be as good for a driveway as smaller units due to the risk of breaking if not bedded perfectly. If you lay them well on a good full bed of wet mortar 4:1 (grit sand: cement)

You should be able to get thicker units like 40mm for use on driveways which was also lessen the risk. 22mm calibrated stuff is much less suitable. Also kandla grey, raj green and autumn brown sandstone are much harder and stronger than fossil mint etc.

 

[MadAlicesDad]

I was looking for 40mm thick flags (any size) online but can't find any supplier. Some do packs of 25-40mm mixed thicknesses, but do you know of anywhere that does just 40mm?
Mike

 

[r896neo]

Sorry cant help you with suppliers, i'm in northern ireland. Contact london stone perhaps and they could perhaps put you on to someone.

Uncalibrated 25mm-40mm would probably be fine especially in the colours i mentioned, just avoid calibrated stone.