Porcelain Porcelain tiles and decoupling membrane?

[Bob2]

Hi all, I would appreciate some professional advice please. I have 10mm porcelain tiles for a garden front path leading to door. The path will be reinforced 120mm concrete.

I am also laying these tiles just inside the door, as this will be part of the same concrete slab, however, the tiles will overlap onto maybe 300mm of 25mm plywood topped with 6mm hardiebacker glued and screwed.

I'd like to know if I can tile direct onto the new concrete slab with a thick bed adhesive, or if I should be using a decoupling membrane first?

Secondly, on the inside, is the membrane a necessity over the 2 different substrates?

Lastly.....which adhesive and grout would be best for this purpose? I prefer using Mapei products, and use Keraflex Maxi a lot, but am unsure of the correct adhesive for exterior use.

I'm confident with my ability to do the job, just need some sound advice on the correct application of products. Your advice is much appreciated as always.

Thanks in advance. Richie.

 

[Dave]

Hi Richie.
How long has the slab been laid and how thick.

 

[Bob2]

Hi Richie.
How long has the slab been laid and how thick.

Hi Dave, it hasn't been laid yet...am planning to do it within the next few weeks. I was going to do a 120mm thick slab with rebar and fibres in as belt and braces.

 

[Dave]

Hi Dave, it hasn't been laid yet...am planning to do it within the next few weeks. I was going to do a 120mm thick slab with rebar and fibres in as belt and braces.

ok , you need to allow the sufficient drying/curing times according to BS5385. Typically 1mm per day for the first 40mm and 0.5mm for the rest of the depth. As for the change in substrate internally, try to fall on a tile joint and use a cold expansion joint

 

[Bob2]

ok , you need to allow the sufficient drying/curing times according to BS5385. Typically 1mm per day for the first 40mm and 0.5mm for the rest of the depth. As for the change in substrate internally, try to fall on a tile joint and use a cold expansion joint

So does that mean I wouldn't need a decoupling membrane? What do you mean by cold expansion joint?