Plasterboard in bathroom

BobProperty

ozskin wrote:

Bob although i would have to check the specific techs I think grohe and gerberit suggest either the use of plasterboard or ply when using the wall hung frame systems. but does this then contravene building regs. I am interested to know

I think it is only in reference to shower areas, wetrooms and the like, not bathrooms areas in general. I also would not be surprised if different manufacturers specifications contradict each other.

Cypher

I am shortly about to do this very topic. My bathroom at the moment has a mix of brick and stud partition walls. The brick walls have all been battened and plasterboarded and then tiled up to the ceiling.

Currently the room has a 1500mm long corner bath which doesn't quite reach one of the walls and has caused problems with moisture getting between the bath and the wall. If I removed the battens, and reboard by dabbing I would probably be able to fit in a 1600mm bath wall to wall which would remove a lot of the problems and make sealing the bath and tiling much neater.

Would board adhesive (dabbing method) be sufficent to hold a fully tiled wall, I'm just curious why the previous refit was battened and the plasterboard nailed and screwed to the battens.

BobProperty

Cypher wrote:

......Would board adhesive (dabbing method) be sufficent to hold a fully tiled wall, I'm just curious why the previous refit was battened and the plasterboard nailed and screwed to the battens.

Suggested possibilities are: it was battened out to make it square, to hide pipes behind, to fill in the gap to the bath but they got the measurements wrong.
Dot and dab and weights of tiles I'm not sure about. I think you would be OK for a splashback of a few ordinary tiles but I wouldn't want to be going floor to ceiling in thick marble.
We are talking just baths here aren't we, not showers, otherwise we start the Aquapanel argument again

Cypher

Thanks BobProperty.

At the moment its a corner bath with a shower. Tiled on plasterboard laid on battens.

The new bath will also be having a shower over it. The tiling will be from bath to ceiling around the bath and from floor to ceiling elsewhere, standard ceramic tiles, although we haven't choosen a design yet.

ozskin

another word of warning the latest generation of large format porcelain tiles that are becoming popular are v v v heavy just to add another spanner in works so even more important to consider the weight and the adhesive you will be using, now we are into specialist stuff and not just off the shelf stuff so be carefull

Cypher

So would it be better to rebatten the walls and screw the new boarding to the battens ?

ictmad

i would say so and use moisture resistant plaster board

ozskin

not necessarily if you are adhering the board to a sound substrate wall over the whole area rather than a few dabs then I can see no problems with the right adhesive. Done right then this could have a more secure fixing than just a few screws in the battens. other than keeping the board level then this reduced depth may be good for you. just a warning though, if you do use large (or small) format porcelain you can not use conventional adhesive

Cypher

I think I will just be using conventional ceramic tiles.

Alan_M_2

ozskin wrote:

Bob although i would have to check the specific techs I think grohe and gerberit suggest either the use of plasterboard or ply when using the wall hung frame systems. but does this then contravene building regs. I am interested to know

This is specifically to do with shower areas and the problems arrive with what we understand the definition of shower to be.

As far as Building regulations are concerned a "Domestic Shower" is a hand held hose extension off a bath tap or similar.

A shower cubicle, power shower, proper shower over a bath is technically a "Wet Area" - Building regs, not my interpretation.

Building regs specific for tiling were changed in 1996 to exclude the use of substrates that are subject to expansion and contraction due to heat or moisture ( i.e. wood).

That aside , a lot of this is common sense. Tiles don't like a substrate that moves, this includes expansion or contraction, so a stable substrate is better, be that plasterboard or tile backer board.

There are so many (freely available) specialist products available for the construction of showers and wet areas, (many of which are no more expensive than plywood) that's there's no reason to be using products that aren't suitable.

There are also a lot of tanking systems available for wet areas, again - a product that has generally been neglected by the building industry at large for many years.

We are technically 20 years behind mainland Europe and the USA with regard to tiling, and the specifications for such.

Also in addition to further comments made above about the weight of tiles, this is becoming a material fact as tiles are increasing in size, the following are the maximum weights for each relevant substrate can support per sq/m including tiles, adhesive and grout.

skim plastered surface - 20kg/m2

correctly constructed stud plasterboard - 32kg/m2

Aquapanel or sand cement render - 50kg/m2

Also, as I'm on a roll here, tiling is not and never has been a waterproof barrier, it is used for aesthetic reasons and hygiene only. Any surface requiring full waterproofing should be done so at the substrate level (see tanking systems).