Cement board for tiling

Up Donegal

Is this material suitable for tiling over?

https://brooksonline.ie/12mm-permabase-cement-board-2400mm-x-1200mm-uk1650

TIA

Dr_Colossus

Yes, it's perfect especially for anywhere involving water such as in a shower as doesn't degrade when wet like plasterboard.

Don't use plasterboard screws to fix as the alkali of the cement will eventually eat through them. You're supposed to use ruspert coated screws like you get in outdoor decking which have a much better resistance. I couldn't source any suitable ones locally so used stainless screws.
Also don't use standard scrim tape for joining, there's a specific cement board tape available which again I couldn't source locally so had to import from the UK.

Despite some claims cement board is not waterproof so tanking is still required for wet areas such as showers.

It's pretty heavy stuff to work with so positioning 8' X 4' sheets around on your own is difficult work. There also a slight flex to it so ensure there's enough battens and noggins in any partitions if wall mounting.

Up Donegal

Dr_Colossus wrote: »

Despite some claims cement board is not waterproof so tanking is still required for wet areas such as showers.

Thanks for that.

Any suggestions as to what tanking system I could use? I'm working at a shower enclosure.

Would this be suitable?
https://www.screwfix.ie/p/mapei-shower-waterproofing-kit/78484?gclid=EAIaIQobChMIupfS7u7N7gIVFWHmCh2WYQFyEAQYASABEgJ1AfD_BwE&gclsrc=aw.ds#product_additional_details_container

Dr_Colossus

Yes, that looks good. Have only used Mapei silicone but it's a well recognised brand for grout and silicone so tanking should be no different. Little surprised that the Mapei kit shows coverage of just 4m2 for a 5kg tub plus 10m of tape. For reference this is the tanking kit I used (although sourced from the UK for €55 which included the ParcelMotel fee)
https://www.goodwins.ie/products/aquaseal-wet-room-system-large-kit.html
and for a 5 liter tub plus 10m of tape indicates a coverage of 7.5m2 which in practice was pretty accurate.

fred funk }{

I recently did a job in the shower and used https://www.tiles.ie/insulated-tile-backer-board.

They're water proof and a pleasure to work with, a simple cut with a stanley knife and it's done. They will give some heat and sound insulation qualities too. They do need to be tanked along the seems and joins.

ElderWanderer

If it's not a silly question, if you're tanking the shower area anyway, why not just tile straight onto the (tanked) plasterboard?

Water degradation of plasterboard isn't an issue if it's tanked properly, as the water won't be able to get into the plasterboard to degrade it. If it's not tanked properly, you're going to have issues regardless of what you use.

Up Donegal

ElderWanderer wrote: »

If it's not a silly question, if you're tanking the shower area anyway, why not just tile straight onto the (tanked) plasterboard?

Thanks for the reply.

It's my understanding that the board I was referring to (see link below) needs to be tanked. Ideally, yes, I would like to tile directly on to the board, but if it could leaad to issues later on, I will tank it.

https://brooksonline.ie/12mm-permabase-cement-board-2400mm-x-1200mm-uk1650

Dr_Colossus

ElderWanderer wrote: »

If it's not a silly question, if you're tanking the shower area anyway, why not just tile straight onto the (tanked) plasterboard?

Water degradation of plasterboard isn't an issue if it's tanked properly, as the water won't be able to get into the plasterboard to degrade it. If it's not tanked properly, you're going to have issues regardless of what you use.

Fair question, it's all about taking every precaution and using belt and braces when water is concerned.
If the area is properly tiled then there should be no need for tanking either. The tanking offers an additional layer of security behind the tiles should they or the grout/silicone fail. If everything fails then the cement board/tile backer board is another layer of security as won't degrade over time.

I had to re-do my ensuite as previous tiler didn't take those precautions and while aesthetically ok there was untold damage being done behind the scenes. Once I cut the grout I was able to peel large 750x450 porcelain tiles off the wall with my fingers. No tanking and plasterboard behind was rotten and mold ridden and subfloor completely soggen.

Replaced subfloor with OSB followed by an additional layer of magnesium board bonded and screwed. Shower area consisted thereafter of a mortar based preslope form re-informed with galvanised mesh, heavy duty pvc shower pan and additional mortar shower tray.
On walls used 3 1/2 sheets of 8'x4' cement board around the shower and moisture resistant plasterboard in the remaining areas around the toilet and sink. All areas primed and anywhere that might see water was tanked.
Everything thereafter tiled from floor to ceiling and had great difficulty in getting epoxy grout for a fully waterproof top layer. Applied a couple layers of tile sealer/impregnator when finished.

fred funk }{

Dr_Colossus wrote: »

Fair question, it's all about taking every precaution and using belt and braces when water is concerned.
If the area is properly tiled then there should be no need for tanking either. The tanking offers an additional layer of security behind the tiles should they or the grout/silicone fail. If everything fails then the cement board/tile backer board is another layer of security as won't degrade over time.

I had to re-do my ensuite as previous tiler didn't take those precautions and while aesthetically ok there was untold damage being done behind the scenes. Once I cut the grout I was able to peel large 750x450 porcelain tiles off the wall with my fingers. No tanking and plasterboard behind was rotten and mold ridden and subfloor completely soggen.

Replaced subfloor with OSB followed by an additional layer of magnesium board bonded and screwed. Shower area consisted thereafter of a mortar based preslope form re-informed with galvanised mesh, heavy duty pvc shower pan and additional mortar shower tray.
On walls used 3 1/2 sheets of 8'x4' cement board around the shower and moisture resistant plasterboard in the remaining areas around the toilet and sink. All areas primed and anywhere that might see water was tanked.
Everything thereafter tiled from floor to ceiling and had great difficulty in getting epoxy grout for a fully waterproof top layer. Applied a couple layers of tile sealer/impregnator when finished.

You're absolutely wrong. Tiles should not be the water proofing layer, they only act as a first defense. Without a tile laid, the enclosure should be 100% water proof.

Dr_Colossus

fred funk }{ wrote: »

Without a tile laid, the enclosure should be 100% water proof.

That's true and that's the way it should be done, no disagreements here. Have read of installers using fiber glass to encase a shower enclosure prior to tiling to get that level of proofing.

Tanking and waterproofing however is a relatively new addition and I'd guess until about 10 years ago was unheard of. There are still a staggering number of professional tilers that don't bother with it. In those cases the tiles were the one and only water proof layer.

GreeBo

Dr_Colossus wrote: »

Tanking and waterproofing however is a relatively new addition and I'd guess until about 10 years ago was unheard of. There are still a staggering number of professional tilers that don't bother with it. In those cases the tiles were the one and only water proof layer.

i dont think thats true, there were DIY tanking kits available 15-20 years ago, I used them myself. I think the problem we have is that in Ireland many tilers see themselves as just that, people who lay tile on whatever substrate is there when they get there, compared to other countries where you dont just get a tiler, you get a bathroom guy.

Dr_Colossus wrote: »

If the area is properly tiled then there should be no need for tanking either. The tanking offers an additional layer of security behind the tiles should they or the grout/silicone fail. If everything fails then the cement board/tile backer board is another layer of security as won't degrade over time.

I would never consider the tiles + grout + silicone to be a waterproof layer, water resistant at best. Waterproof grout is relatively new and even then you are relying on proper install and no movement.

ULMarc

I'm looking for advice on fixing cement board through 50mm PIR into studs. The cement board screws I'm finding aren't long enough.

So wondering what a good alternative would be? Do plasterboard screws fit the bill? Accompanied with washers maybe?

the_pen_turner

go stainless. normal type screws