Cement Boards....

[grouchfungus]

Hello. Not posted here for a couple of years. And am a bit dejected to say the least. So -

What's the general opinion regards Tanking Cement Boards when they are fitted in a bathroom containing a shower enclosure? To clarify, I'm not talking about when they are fitted in a wetroom.

Thanks, Grouch.

 

[AliGage]

Welcome back.
If its in a "wetarea" then it should tanked.

 

[SJPurdy]

Tanking is recommended in general shower wall tiling to protect a water sensitive substrate from water seeping through the non water proof grout (grout resists water but if the surface is constantly wet then the back surface of the grout will also be damp). Therefore if a cement board is used then tanking is not required as the substrate (cement board) is presumably not water sensitive

 

[Alan.P]

Welcome back.
If its in a "wetarea" then it should tanked.

I agree

Therefore if a cement board is used then tanking is not required as the substrate (cement board) is presumably not water sensitive

Not really correct, in certain boards water will pass through the board so it should be tanked, cement boards range but regardless should be waterproofed in wet areas, this drives me mad, if weights allow it then why not use plasterboard instead, tanked is tanked ??

 

[grouchfungus]

Thanks for replies. It'a annoying to say the least... Have used cement board for many years and this tanking question is still a grey area..... Knauf say you don't generally have to tank in a shower enclosure situation. However if you ever have a problem with an installation a tile supplier/manufacturer will cop out by quoting BS on tanking etc. So why use cement board in the first place? Using plasterboard and tanking with a decent tanking system ie. The ardex wpc kit will cover you with regards BS's etc. And give

 

[SJPurdy]

Or use Wedi board with joints sealed with their 610 sealant/adhesive. It's much easier to handle and cut than cement boards and it is waterproof.

 

[Concrete guy]

I used to fit showers in Aquapanel and tank with the BAL system. This was before it was included in BS and tanking was a strange thing that only the Americans and Europeans did. That was just the way I worked.

I figured if I used a structural board and tanked it I'd covered all bases.

The only issue I used to have though was because I specialised in natural stone I would often be fitting a product that exceeded the weight limit of tanking (but not the board), so you had to go without tanking or use mechanical fixings. So sometimes you'd need to think laterally and use an impervious substrate like Wedi board.

There isn't a one size fits all solution, in a domestic environment tanked plasterboard is perfectly acceptable but it's not the best solution and I was always keen on finding the best solution possible that wasn't stupidly expensive.