Hi I am renovating a bathroom in a 1960s bungalow. the walls are stripped back to the Cinder/Breeze block. I would like to use insulated tile backer board dot & dabbed to the block walls then screw fixed through the dabs for large format tiles. I really dont want to batten it out as I feel this will impact the available space. I am unsure what adhesive to use for the dabs, plasterboard adhesive is not the right stuff as it will not adhere to the boards properly(?). Tile adhesive will stick to the boards but will it be ok 10mm or more thick in the dabs and will it stick to the blockwork. Do I need to SBR(?) Prime the blockwork walls they are a bit dusty from the old plaster. Some advice would be appreciated. cheers ian PS Just had a thought about battens. Would it be OK to Fix the battens and insulated board with one masonry screw (with washer) through the board and batten or would that over compress the insulated backer board? Is that just a daft idea
Also i have read some posts about using Foam to fix boards. would that be okay for this application and would that need screw fixing as well? Ta Ian
Why try posting on uktilingforum.com there are loads of proffesional tilers who will give advice on your question
Look through my post on here about backer boards. Seal the wall with sbr, pre-drill the backer boards (use wedi or marmox for waterproof insulated boards) and then apply dabs of rapid set tile adhesive to the boards (especially where your holes are but spread out sensibly). They will suck to the wall and you can then tap on your level with a mallet to level out. If you're worried about them moving then brace in place with a timber whilst the adhesive sets. It won't take long for them to be secure. I waited until the next day and then drilled through the pre-drilled holes and used 8mm dowels (also called spankers) to secure. One in each corner (about 100mm in) and one in the middle. I got a good result with my boards with this technique. Good luck. Note that if you use cheap boards then they will have to be tanked as well to make them waterproof.