What primer should I use on a Besser block wall prior to tiling?

[RyanL1]

Hi All,

We have had a besser block wall built for the entrance to our driveway, which we will be having stack stone tiles applied to. However, we have been told that the blocks can sometimes "weep" through the mortar lines, so it is advisable to prime it before tiling.

Is there a particular product we can use to do this?

We also have a rendered brick pier as part of our facade to be tiled. Should that also be primed beforehand and can we use the same product as the wall?

cheers

[MitchellMc]

Hi @RyanL1,

It's best to speak with the manufacturer of the stacked stone to determine the most suitable products to be used over your besser block wall. If the stack stone is natural, then they are susceptible to tile glues that are acidic and have long cure times. I've had some discussions with our various glue suppliers, and Sikaflex 11FC Plus Polyurethane Adhesive Sealant would be the best D.I.Y. product to use on our stacked stone products. I would advise to purchase the sausage 11FC and apply a liberal amount of the adhesive all over the back of the tiles and not just in dots or lines. You should find a QEP 6mm Square Notch Handyman Adhesive Trowel useful in getting a consistent coating. 

Regarding the rendered pier, it's typically not a great idea to tile over render. You are essentially hanging an additional weight off the render, which can cause it to delaminate. It would likely be best to install fibre cement sheeting over the render that you would glue to it and then also use physical fixings into the column for strength. You can then tile over the sheeting. A similar method could be used on your wall if you are concerned about weeping.

Please let me know if you have any questions.

Mitchell

[RyanL1]

Thanks Mitchell, much appreciated. I did ask the supplier, but did not get a response, hence the query here. Will also double check with the tiler when we find one.

Will get some fibre cement sheets for the render, that is easy enough. Any particular adhesive for the sheets I should be using? and from my research, I need to go at least 50mm into the bricks with the screws, so I'm guessing a 60-65mm masonry screw and plug will be sufficient and will account for the thickness of the render?

sorry, this is all new to me. 

cheers mate!

[MitchellMc]

You can use Liquid Nails @RyanL1, and a 65mm masonry fixing sound just about right. You can use countersunk Dynabolts instead of screws and plugs if that's more convenient.

Mitchell