Porcelain Slabs on concrete base - prepping the slab

[WanderOverYonder]

Morning all,

I'm in the process of covering over a 3600mm square concrete slab in my garden. It was an old base for a shed that's now gonzo.

The chief financial officer has approved 900 x 600 Kandala Grey porcelain slabs (20mm thick) and so I've ordered 30 to cover any wastage etc.

Due to the height of a drain channel that sits the end of the slab where the fall runs to, I need to use as thin a bed of adhesive/mortar as possible and so would be looking to use a cement based (powdered) external tile adhesive to give a c. 6mm bed and I understand that I need to use a primer slurry (SBR/Cement) on the tile backs to improve adhesion.

My question is, do I also need to prime the concrete slab under the adhesive? I see many conflicting opinions on this.

The area will be used as an occasional seating area but also to take a small 6 x 6 greenhouse.

Thanks in advance all.

 

[yorksbuilder]

Go with what the adhesive manufacturer recommends. Usual practice would be to pressure wash the concrete and prime with a diluted SBR primer before tiling to ensure it's sealed

 

[WanderOverYonder]

Go with what the adhesive manufacturer recommends. Usual practice would be to pressure wash the concrete and prime with a diluted SBR primer before tiling to ensure it's sealed

Thank you. I have done the pressure washing at the weekend as it was manky (it's made the surface quite rough with little bits of the concrete coming loose). I'll get some more SBR and give it a seal - if it ever stops raining here in Fife.

 

[simplesteve]

No rain here in Ayrshire for the next few days; I’m sure you’re aware though to keep an eye on the temperature, you don’t want it below about 5 degrees for a few days before and during laying …..