Slates onto concrete blocks

[mikert]

Hi forum,

I'm about to fix 20 M2 of natural slate tiles, 300mm x 300mmx 10mm onto standard concrete 4" blocks internally.

I got the slates at a good price, but the seller is trying to get me to buy primer and adhesive off him as well.

I may well need them, but thought I'd check with the experts first.

Adhesive is Ultra Tile ProRapid RS and primer is Ultra Tile Prime IT FP Flexible Primer. I know I need adhesive, and this seems OK, but would I need primer too? The adhesive is cementitious so don't see the need for primer with concrete blocks.

While on the subject, should I seal afterwards also? They'll be in a stairwell so won't be getting wet or wear & tear.

Thanks in advance,

Mike.

 

[tpt]

the seller is right, you need the adhesive because concrete blocks are very porous. its very different to fixing onto a concrete screed. Frankly its not worth skimping.

Make sure you fix them with a notched trowel and spot them.

Yes you should seal them, before and after you grout, but you'll get away with not doing so if you like.

 

[mikert]

Ok, thanks tpt.

I understand the bit about needing adhesive, is the make he's suggesting recommended in your opinion?

Also, is sealer and primer the same thing?

 

[tpt]

Sorry!

No sealer and primer are different. the sealer is an impregnator really, its clear and soaks into the slate a little to close off any porosity. Look at Lithofin, LTP or Fila ranges.

Nothing wrong with Ultra, its a popular trade choice.