What surfaces to prime

[Anna Rack]

Just wondered what surfaces to prime when tiling. Planning on acrylic as PVA seems to be frowned upon.

Got some 6mm cement faced backer boards to fix to green chipboard. The chipboard is quite waxy so will this benefit from a primer? Will also be screwing with washers and taping joints. Do I prime the underside of the backer board as well as the top face? Presumably you don't prime the (mesh backed) 50mm tumbled marble mosaics?!

Thanks in advance.

 

[beanz]

No need to prime the chipboard or the backer boards. I wouldn't use the washers either.. You'd be better off counter-sinking the screws.

 

[Rookery]

Same for me. Wipe the floor and back of the boards with a damp sponge to remove any dust/dirt before you start.

 

[beanz]

Oh! And you know to glue, as well as screw, the cement boards?

 

[Anna Rack]

Thanks.

Was planning on sticking the boards to the floor with adhesive and then screwing when set.

Don't think countersinking the screws would work as it's a foam board and they'd go straight through!

So I don't need to prime anything during the job?

 

[Ian]

Thanks.

Was planning on sticking the boards to the floor with adhesive and then screwing when set.

Don't think countersinking the screws would work as it's a foam board and they'd go straight through!

So I don't need to prime anything during the job?

Screw the boards whilst the adhesive is still wet, not after it has set.

 

[White Room]

Whats the name of the boards as backer boards as I refer to them as cement boards without the foam as in Hardie.

 

[DHTiling]

If they are cement faced polycore boards then min depth is 10mm and special washers are required... if they are solid core boards like hardibacker etc then no washer required and 6mm can be used in deflection is minimal.

 

[Anna Rack]

They're 'prowarm' tile backer boards. Had a look at the installation instructions and they say they can just be screwed without adhesive onto the floor, but I'd rather have both to be sure. They suggested normal stainless penny washers.

They also said 6mm would be fine on a level floor - wouldn't the thicker boards be more likely to compress?

 

[beanz]

If they are cement faced polycore boards then min depth is 10mm and special washers are required... if they are solid core boards like hardibacker etc then no washer required and 6mm can be used in deflection is minimal.

They sound like fun!?! How do you go about tiling on boards with screws and washers sticking up? Especially mosaics!?! Sounds like an absolute nightmare!

 

[Anna Rack]

They sound like fun!?! How do you go about tiling on boards with screws and washers sticking up? Especially mosaics!?! Sounds like an absolute nightmare!

First time I've used these boards but it seems the screws and washers would compress into the surface when tightened so would end up flush.

 

[beanz]

Oh I see.. You should post up some pics, it'd be interesting to see it coming together

 

[Anna Rack]

Back to the orginal question, I guess I don't need to prime anything unless the surface is dry/dusty? Or is it best as a matter of course anyway?

So you've never used the foam backing boards? There seem to be endless posts on the forum recommending using them over plywood.

It's all a learning curve for me... you try searching the internet to do something 'properly' and end up wishing you'd never started the job. Anyway I seem to be following the path most pros seem to suggest, only question mark is whether I should have used the thicker board.


Will get some pics up once things get moving.

 

[DHTiling]

They sound like fun!?! How do you go about tiling on boards with screws and washers sticking up? Especially mosaics!?! Sounds like an absolute nightmare!

The washer pulls into the board, nothing is proud if done right.

 

[Anna Rack]

Oh I see.. You should post up some pics, it'd be interesting to see it coming together

Here are my efforts so far, apart from a few tiles with a bit of lippage I am pretty pleased with the result. I guess a beige grout would be the way to go?