Priming block wall before sticking Marmox?

[LEH]

I was going to fix backerboards with a continuous bed of adhesive (presuming they're not too squiffy), or dot-and-dab plus fixings if they look nasty. The wall is a standard thermalite type block thing. Might be a silly question but do I need to prime the wall or is the adhesive all right to go straight onto it?

 

[Dumbo]

I would prime every time . Also i would prime Marmox boarding even though some people will say you don't need to doesn't mean you can't. Belt and braces . I would also use mechanical fixings no matter how good or bad the walls are .

 

[LEH]

Yeah I think I agree on mechanical fixings. Would Mapei Primer G be OK for blockwork?

 

[Tile Shop]

http://www.marmox.co.uk/uploads/cat...tions/MarmoxMultiboardfittinginstructions.pdf

These are obviously on the condition that the blocks are in top knick. If they're not, I'd go for both full coverage and plenty of screws.

 

[LEH]

Yeah, had already read those. Highly doubt in top knick so will do as you say. Was just wondering if you could put adhesive straight onto the blocks, which is what they seem to imply in the instructions.

 

[Tile Shop]

Ahhhh.... priming. Missed that bit even though its the title of the thread. DOH! Sorry, typical Monday and brain slightly mashed. But yeah, blocks are porous as hell, so best to prime. Primer G will be fine.

 

[Bond]

Thermalite blocks are a extremely high suction background, would dampen blocks first with water, prior to applying at least two coats of dilute SBR.

 

[Chris Gibbs]

prime, prime and prime again they will suck the life out of the adhesive. oh and screw too. don't just rely on sticking with adhesive though.

 

[Bond]

If also screwing boards, check on there suitability for use on thermalite, don't take standard screws to well.

 

[LEH]

Cheers guys. I should be careful throwing terms around, not sure it's thermalite. It's early 70s so might be the older breeze block type, I'm not an expert on construction. I suppose that doesn't make too much difference though so I'll be sure to prime and make sure it's well fixed.