Joe wrote:
I'm looking to replace the broken slate of an old driveway with
some kind of reasonably decorative paving slabs. I'm warned that
a minimum thickness of about 45mm in cast concrete slabs is needed
for parking a car on, which seriously limits the possibilities.
Basically, only fairly boring slabs in one or two sizes come that
thick.

I see a lot of Indian sandstone advertised, at about the same price
as decent concrete. Thickness is 25-35mm, but in sandstone this is
said to be OK for the load. Can anyone confirm that? Has anyone
actually used this for a drive?

I have used this on my patio and in my house and I reckon its stronger
than equivalent thickness pre-cast concrete flags. However as others
have alluded its how they are supported which will be the key. I imagine
a full mortar bed on something quite solid would be a must.

I have also seen this stuff used on a farmhouse driveway up the road and
this looks pretty good 2 years after I started walking past that drive.
Not sure what kind of traffic it gets though (probably nothing more than
the odd range-rover & horse box). No idea what the flags are laid on to
either.

Also, IIRC in my case the flag thickness varied from 15mm to 50mm thick
at the extremes. If you get the opportunity to hand pick thick ones from
a crate it might help a little.

HTH,

Alex.