Laying slabs on concrete pad

[healey99]

Hi

I need some advice on how to lay slate slabs on an existing concrete slab.

The slab is 150mm deep, reasonably level and been down for 4 years. It is 2.4m x 2.4m.

I have around 35mm depth to make up to match surrounding levels. The slabs are 20mm leaving 15mm.

What is the best approach to laying these slabs.

I have looked at using thick set cement based tile adhesive, but this is expensive and difficult to work with due to rapid drying times.

Can the slabs be fixed with a regular mortar and if so what would be the best mix.

Any advice greatly appreciated.

[lutonlagerlout]

15 mm is tight for a proper bed
I would prime the concrete and the underside of each slab with an SBR slurry,
then bed them on to a very wet mix (wet bricklaying mortar mix) with SBR in the mix

its not impossible but it will be hard work to get right
you still need to use sharp sand and may end up with picture framing
LLL

[healey99]

Thanks for the advice, I will give that a go.