Granite slabs - bedding and grout

[johnyone]

I am going to put granite slabs on a surface which is part solid concrete and part beam & block. This is an extended part of my house floor - effectively a balcony, so I can't use a bed of sand and don't want to use mortar in case the cement causes "picture framing". I am thinking I could lay a bonded screed and then use external tile adhesive. What does anyone think of this? Also, although granite does not usually get installed with a grout (so I'm told) I am thinking of using one because I don't want water under the slabs because of frost issues. Is there a possibility that tile adhesive or grout could cause "picture framing"?

[Tony McC]

Mortar: cement based and risk of picture framing

Tile adhesive: cement based, therefore same risk

If you soak the granite 24 hours before laying, then use a full bed, with a slurry painted onto the underside as described in a separate thread, then you should be fine.

Picture framing most commonly arises in porous paving that is parched dry and then jointed with a wet cement mortar. Address each of those problems and you should eliminate any risk of picture framing.

So: soak your paving 24 hours in advance and consider using a stiffer cement mortar or even a resin-based mortar for the jointing.

[johnyone]

OK I will look up this thread. Many thanks