Tanking, aqua panel & skimming.

[GaryinAshby]

In my new bathroom extension I was going to use aqua board for the whole room. Having priced it up (& had a sit down....) I've decided to use plasterboard & Aquapanel only in the shower cubicle.

The entire bathroom will be tiled floor to ceiling, so.......

Do I need to skim the plasterboard and aquapanel, or will it be okay to bond the tiles straight to the plasterboard and aquapanel? If so, should they be PVA'd first?

What about plasterboarding the whole lot & tanking the shower area? What exactly is tanking & how does it work?

Thanks.

 

[Richard C]

In my new bathroom extension I was going to use aqua board for the whole room. Having priced it up (& had a sit down....) I've decided to use plasterboard & Aquapanel only in the shower cubicle.

Wise move. That’s fine but I’d also use Aquapanel behind the bath as well; use moisture resistant plasterboard for the remainder.

The entire bathroom will be tiled floor to ceiling, so.......
Do I need to skim the plasterboard and aquapanel, or will it be okay to bond the tiles straight to the plasterboard and aquapanel?

You don’t need to skim, just tile straight onto both the PB & Aquapanel; in fact you can't use conventional plaster on Aquapanel. Use a trade quality tile adhesive & grout (BAL) not DIY shed stuff.

If so, should they be PVA'd first?

No

What about plasterboarding the whole lot & tanking the shower area? What exactly is tanking & how does it work?

Personally, I always use Aquapanel but Tanking will work just as well. Tanking places a waterproof membrane between the back of the tiles & the wall/floor being tiled; it’s generally used in wet rooms.

 

[GaryinAshby]

Thanks Richard. No bath, just a shower cubicle so I'll use Aquapanel & moisture resistant PB elsewhere.

I never touch DIY store tile adhesive....... used it once, NEVER again!

 

[kingandy2nd]

I don't disagree with anything Richard said but I went for the tanking method in my bathroom.

Link to my previous post can be found here:

//www.diynot.com/forums/viewtopic.php?p=908639#908639

I found to be very easy to do - no issues with how to fix the aquapanel to the walls nor any differences in the width of plasterboard or aquapanel which can cause issues if you want a flush finish.

Also it worked out cheaper for me.

 

[Richard C]

I don't disagree with anything Richard said but I went for the tanking method in my bathroom.

Link to my previous post can be found here:

//www.diynot.com/forums/viewtopic.php?p=908639#908639

I found to be very easy to do - no issues with how to fix the aquapanel to the walls nor any differences in the width of plasterboard or aquapanel which can cause issues if you want a flush finish.

Also it worked out cheaper for me.

Whatever floats your boat, both will work equally as well. Tanking is both cost effective & essential on wet rooms but Aquapanel lining is a lot quicker on well defined areas such as shower or bath surrounds & fixing/flush finish is not the problem it may, at first, seem!

 

[GaryinAshby]

Thanks, I'm going with the Aqua panel as it comes in 12.5mm thick, the same as the plasterboard I'm using. My blockwork walls are good so hopefully I should be able to get both Aquapanel & plasterboard to butt up against each other flush. I'll dot & dab the PB as usual & do the same for the Aquapanel, but also use stainless screws for a mechanical fastening.

 

[AndersonC]

Just the post I was looking for! I'd posted the info below in the "my projects section"

Floor - currently T&G pine, final condition will be tiled with UF heating. Intend to replace T&G with WBP ply - is 18mm or 25mm thickness best? Room is only 6' square.

Walls - currently lots of lime plaster & layers of tiles. Intend to take back to brick and batten & board. I will use a cement backer board in the shower area. Do I need to use this behind the sink as well? For the rest of the walls I am intending to use a "moisture check" type plasterboard. Is this OK or overkill? For battens I am intending to use 2x1" rough cut battens which are described as "50 x 25mm Slate/Tile Batten NW Green Treated " in the shop. Are these suitable?

Ceiling - currenly un-insulated (winter = brrrr) with lath and plaster directly on the rafters. I intend to rip this out, introduce 2" insulation between rafters (difficult to fit over L&P due to height contsraints) ensuring suitable ventilation gap, then overboard with a "vapour check" type plasterboard before finishing with either a skim or timber of some description. Again does this sound a reasonable way to proceed?

Any suggestions appreciated, thank you.

The essence being to work out what kind of board I needed where. In summary:

What kind of battens are recommended for boarding out a bathroom?
Would moisture check be recommended for ceiling too, or the foil backed vapour check?
Would aquapanel behind the sink be recommended?

Thanks all

 

[Richard C]

I just could not get the quotes to work (I think it has something to do with the link to your other post) so I’ve used italics instead!
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Just the post I was looking for! I'd posted the info below in the "my projects section"

I can see there is relevance but it’s always best to start your own thread.

Floor - currently T&G pine, final condition will be tiled with UF heating. Intend to replace T&G with WBP ply - is 18mm or 25mm thickness best? Room is only 6' square.

18mm WBP ply will be fine 25mm even better but this will give you a significant difference in floor levels. Assuming the U/F heating system is electric; these should be installed with insulation board below or it will take ages for the system to heat up. I have one but personally I wouldn’t bother again; with the additional expense & running costs I don’t think they are worth it unless you intend to spend a lot of time standing around in your bathroom.

I will use a cement backer board in the shower area. Do I need to use this behind the sink as well?

No; moisture resistant PB is fine.
For the rest of the walls I am intending to use a "moisture check" type plasterboard. Is this OK or overkill?

Not sure what you mean by moisture check PB; use moisture resistant PB not foil backed duplex board, this is intended for a completely different application.

For battens I am intending to use 2x1" rough cut battens which are described as "50 x 25mm Slate/Tile Batten NW Green Treated " in the shop. Are these suitable?

If the walls are basically sound & reasonably flat, I would dot & dab the boards, far quicker & cheaper; there is a method of fixing Aquapanel in this way!

Ceiling - currenly un-insulated (winter = brrrr) with lath and plaster directly on the rafters. I intend to rip this out, introduce 2" insulation between rafters (difficult to fit over L&P due to height contsraints) ensuring suitable ventilation gap, then overboard with a "vapour check" type plasterboard before finishing with either a skim or timber of some description. Again does this sound a reasonable way to proceed?

That’s a very messy way of going about it, if it’s sound I would just overboard it. Have you thought about introducing a false ceiling below & lining this with high efficiency foil/bubble wrap insulation; I used this method to good effect on a single skin garage wall which used to get freezing in the winter. I used vapour check duplex board but this was to check any damp from the garage; you wouldn’t need this on your ceiling.

 

[AndersonC]

Richard, thank you for the reply

The ceiling does fall quite low so putting a false ceiling in below this would lower the ceilnig too much for us. I will certainly look at a false cailing under part of the taller area of the room. I was thinking vapour check to help reduce the likelihood of moisture from steam entering the roofspace (but I will keep this ventilated).

I will re-consider the UF heating. It seems a lot of effort and I never hear anyone giving it significnt praise. Perhaps I could incorporate a second small radiator into the bathroom to ensure plenty of towel drying space.

Walls (well the one I have stripped so far, is not at all flat or sound). I am going to mix up a load of mortar just to tidy up the pointing which is crumbling out from between the blocks. Dot and Dab would require a lot of work, whereas I could pack battens out to ensure plumb and level. Rather than use PSE timber I thought that treated battens intended for slates would be OK for this job.

The plasterboard I was going to use for the walls is "Lafarge Moisturecheck (moisture resistant)" - sounds like this would be appropriate - would this be suitable for use on the ceiling?

Thanks again for your help

 

[Richard C]

Richard, thank you for the reply

The ceiling does fall quite low so putting a false ceiling in below this would lower the ceilnig too much for us. I will certainly look at a false cailing under part of the taller area of the room. I was thinking vapour check to help reduce the likelihood of moisture from steam entering the roofspace (but I will keep this ventilated).

Steam in the roof space! Forgive me but using foil backed Duplex board is a total waste of time & money. The foil is on the back to prevent damp entering the PB from behind, not the other way around; steam would have to travel through the PB before it reached the foil & by that time the PB would be mush anyway. I assume it’s an just an ordinary bathroom & not a sauna your installing & I assume you have an extractor fan? It is a building regs requirement!

I will re-consider the UF heating. It seems a lot of effort and I never hear anyone giving it significnt praise. Perhaps I could incorporate a second small radiator into the bathroom to ensure plenty of towel drying space.

Personal choice/decision but I wouldn’t disagree with you.

Walls (well the one I have stripped so far, is not at all flat or sound). I am going to mix up a load of mortar just to tidy up the pointing which is crumbling out from between the blocks. Dot and Dab would require a lot of work, whereas I could pack battens out to ensure plumb and level. Rather than use PSE timber I thought that treated battens intended for slates would be OK for this job.

You can use treated timber but I don’t think using untreated would present any problems either; if you use the right products, moisture/damp just isn’t going to get through there from the bathroom.
I don’t agree with your view that dot & dab would be more work than battening; I do both & I prefer to D&D every time! It will accommodate significant discrepancies in level as long as its not bordering on the ridiculous.

The plasterboard I was going to use for the walls is "Lafarge Moisturecheck (moisture resistant)" - sounds like this would be appropriate - would this be suitable for use on the ceiling?

I tend to use only Gyproc products but the Lafarge equivalents are fine; you can use it for the ceiling as well.

 

[AndersonC]

Richard

I was being my normal pessimistic self in thinking that water vapour could somehow get into the roofspace above the bathroom. Taking a more pragmatic view, this is highly unlikely unless the ceiling itself had absorbed sufficient moisture to degrade it such that significant moisture could pass through it. Thanks for putting me on the straight and narrow.

I do have an extractor fan and opening window so it shouldn't be a problem. Thanks for the lesson in the use of foil backed boards.

WRT battens I will simply go for the most cost effective option.

Think I will look into an additional radiator instead of underfloor heating, you can't hang towels on underfloor heating for a start!

Thanks again

 

[Richard C]

Think I will look into an additional radiator instead of underfloor heating, you can't hang towels on underfloor heating for a start! Thanks again

Having tried an aftermarket electric element system, I'm not a big fan! It works reasonably well as long as you keep it ticking over on low but turn it off & it seems to take ages to get going again + it can really can be expensive if you’ve a large floor area as I have. If building new I would, however, go for a wet under floor heating system rather than conventional radiators. A developer friend of mine has been installing these in his new properties for around 3 years now on both ground & 1st floors & they are both impressive in use & economical.