Laying sandstone slabs on top of quarry tiled porc - Laying sandstone on top of quarry tiles

[goose66]

Hi everyone,

I have an outdoor front porch that is tiled with quarry tiles, i have some sandstone flags left over from my patio and would like to put these down on the porch...

Can i lay these directly on the existing quarry tiles and if so what should i use as an adhesive? I've been using an SBR/cement slurry rolled onto the bottom before placing them on my mortar bed for the patio - would the SBR/Slurry be enough to adhere them to the quarry tiles with maybe a very thin mortar bed for levelling purposes (obviously the porch is perfect level wise but the flags are not all perfectly equal in thickness)

i should also mention that the porch is covered so i'm not worried about drainage beneath the slabs, there is a nice fall away from the house too.

Any advice would be much appreciated!

[Tony McC]

SBR or another bonding agent would be essential, but you also need to consider the impact on the DPC. If the paving laid over the tiles would be less than 150mm below DPC, that could well be a breach of Building Regs.

You need to question whether such a breach is worth the risk.