Plasterboard or Backer boards

[Paul348]

Right after a bit of help and advice please if i may, i have done a few searches but it is not clear cut.

I am sorting out our bathroom ripped it all out and started from fresh, i have got a lot of good info from here and put it to good use so far so thank you all

I am installing a “p shape” shower bath, i have made new stud wall at the shower end of which i am going to tile with mosaic tiles. i am also putting in 2 recesses 300x 200 by 100mm deep for putting shower gel, shampoo etc on to. These will also be covered in the same mosaic tiles.

I was going to use moisture resistant plasterboard on the face of the stud work and make the boxes for the recesses with 18mm wpb plywood.

Do any of you see an issue with this? Or should I use tile backer boards instead of the plasterboard?

Thanks in advance

 

[Master of None]

After taking advice from this site I used Aquapanel for the wall of the shower I was dismantelling and tanked the remaining plaster board at side of shower. No problems upto now (over 2 years.)
PS Aquapanel does not take plaster or tanking well.

 

[Richard C]

Use MR plasterboard generally except if your fully plastering the walls; for wet areas use 12mm waterproof tile backer boards; do not use PLY as a tile base on walls; do not use PVA to prime anything; only use primer where adhesive manufacturer recommends it; only use quality trade flexible addy/grout of the correct type for your tiles. Use cement based addy for tiles larger than 300 x 200mm & gypsum plaster/boards must be primed to avoid reaction with the cement. If your ½ tiling & want to plaster MR boards, they must be primed first; you can plaster Aquapanel with the right prep but why would you want to; no need to tank it unless your constructing a wet room, just tape & seal the board joints which must not coincide with any tile grout lines.

 

[tictic]

for all wet areas and your recesses..(put these at a slight tilt so water run down and off).. use a tanking membrane shultuter/homelux/dura..and use tape at ALL joins...

has for mosaic make sure you use a mosaic fix addy and a bloody good grout..cos that how ya get failures 10/10(bad grouting)...with mosaic..
best of
tt.

 

[Paul348]

Thanks all for your replies very helpful

I called up Bal tech line and had a nice chat with David Spruce. He was very helpful and advised that making the revels out off plywood would not be an issue as i would be tanking the area anyway.

So i have gone for Aqua boards and WPB 18mm ply with and sealed the backs and sides with SBR.

The mosaic i am using are a mix of glass, stone, ceramic and stainless steel so Dave recommended Rapidset flexible as it will not bleed though the glass on the mosaic.

As you can see by the photos i have built the stud wall and made and fitted the plywood boxes / revels, thanks to tictic i made the bottom fall slightly to the front.

The large hole below them is for a Tilevishion TV ( The wife’s Idea)

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Now i have asked a few plasterers to come and have a look but so far one has turned up, but as yet he has not got back to me.

As i have a 9 inch wall with render to the outside, I was going to use plaster board with the insulation on the back.

My questions are this
I believe you can dot and dab this ? if so is there any specific adhesive to use
I have never done any plaster work as such well not dot and dab, but i do class myself a competent person how hard is it ?

How thick do you put the adhesive on and do i put it on the wall or the board.

I have a difference in wall levels due to new and old bricks; i have tried to show these in the photos below. This is 25 mm in places, do i screw a piece of wood here to build it out level with the rest of the wall and dab adhesive to it and then screw when set ??

I know batten and insulation the plaster boad would be better but i just don’t have the room.

Again thanks for all your help.
Regards Paul

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[Richard C]

I called up Bal tech line ---- He was very helpful and advised that making the revels out off plywood would not be an issue as i would be tanking the area anyway.
So i have gone for Aqua boards and WPB 18mm ply with and sealed the backs and sides with SBR.

Sorry Paul but I fear I'm going to upset you with this lot I would still not have used ply even with tanking; it’s wood & wood isn’t dimensionally stable if it gets damp/wet & the back/edegs will be the most vulnerable even with tanking. Plaster board or waterproof tile backer board is far easier to cut & work with.

With regard to installing insulation boards, you need at least “Thermaline Plus” as this has an integral vapour barrier. This can be dot & dabbed but also requires mechanically fixing with nailable plugs, however, that looks to be a huge hole in the brickwork there & your going to have one hell of a job to dot & dab anything over that the way it is. And what are you going to do about that pipe work? Not trying to be over critical but it looks a like a dogs breakfast to be honest!

The large hole below them is for a Tilevishion TV ( The wife’s Idea)

I assume you are aware of the regulations applicable to electrical circuits/appliances & bathrooms? & that wiring certainly doesn’t comply with Regs. I would advise you reconsider battening & get the electrics correctly installed by a suitably qualified (Part P) spark.

 

[Paul348]

Thanks for your reply Richard

Re the wood V Aqua panel my take on it is this and i don’t mean to say you are wrong

Whatever you use you are attaching it to wood just like you do on the floor so i just don’t see the issue. If i used aqua panel to make the boxes i still would have had to screw it to wood. I did consider lining the boxes with aqua panel but Bal said no need. I cannot see how the moisture can or will get into the back of the stud work unless we have a roof leak or someone stands there and throws water at it.

Regarding the electrics they are being done by a certified sparkly, the box you see on the photo is the warm up under floor heating control,there will be a glass ceiling to bath shower panel there so will be outside of the splash zone.

Regarding the TV it is a proper bathroom TV rated at IP65 and is powered by a 24 v supply via a transformer. The transformer is to be located outside of the bathroom; all meets the Niceic fact sheet here http://niceic.com/Uploads/File1219.pdf

Regarding the pipe work, i was going to let it into the thermaline plus.

Regarding the walls it is a 1800 cottage so not all the walls are straight so have to work with what i have got, i know it is not ideal! Before i started someone had tiles onto vapour board with the silver lining on the back, this in turn was dot and dabbed the concrete render and as you know you cannot dot and dab vapour board so it was all loose. I knocked concrete render off all of the walls and i am left with what you see, i only have issue with that wall the other walls are pretty good.

I can fix 25 mm battens on the wall and put moisture board or aqua panel on top but i would not have any room for insulation hence why i was going to go for 30mm thermaline plus.

After i posted last night i spent the next 4 hrs looking on the British Gypsum site and learnt quite a bit about the different type of boards and fixing them.

Still unsure what to do now though