Waterproofing walls & floors - How much is enough?

[Pgeddon]

Hi all,

Having a new bathroom fitted this week and looking for advice on how far we should go with waterproofing it.

The bathroom will be tiled floor to ceiling and will have a penta/corner shower cubicle, a sunken bath. Pan to wall toilet and a vanity unit / basin.

top down Layout and renders below.




After seeing a few horror stories on youtube of bathrooms not being appropriately waterproofed, rotting plasterboards and wall studs etc. I asked our plumber/fitter what they intended to do waterproofing wise...i.e waterproof boards / tanking etc.

Their reply was that they'd planned to use tile backer boards for where shower cublicle and sunken bath are (including steps etc). They said they didn't plan to tank or board the remaining areas and just doing the boards for the shower/bath area should be enough.. I've outlined on the images below the areas that they've said will be sufficient.





I guess my questions are

:- Does this look correct and will it be sufficient for the areas outlined to be done with tilebacker boards, or should they be tanked too?

:- For the remainder of the room where they've said there wont be any tilebacker boards, it will be tiles directly onto soundbloc acoustic plasterboard...is this an issue? would it be wiser to tilebacker board the remaining areas too? or tank those areas that wont have the tile backer boards?

thanks for your help as always guys!


Edit:- these are the latest youtube links I saw about waterproofing, found them quite informative -

 

[ShaunCorbs]

Tbh that bathroom looks impressive I would be installing schluter and doing the whole bathroom

Bathrooms & wetrooms | Schlüter-Systems

The essentials for every wet area. Whether you are planning a bathroom or wet room as part of a new build or renovation, Schlüter-Systems offers everything you need for preparation and protection when laying tiles or natural stone.

www.schluter.co.uk

Do you know what fitments eg items your going for eg shower toilet etc

 

[Pgeddon]

Do you know what fitments eg items your going for eg shower toilet etc

I know the fitments yes. I have all the shower toilet bath etc all here already.

Those schluter boards look very similar to the element ones that will be used in the blue outlined parts of the pictures above.

If you’re putting the schluter over the top of the plasterboard, Do you tank over the top of the schluter boards? Or inbetween the plaster board and schluter? or neither?

 

[Ben-gee]

Tbh there is no real need to tank the wall with the vanity.
I just Re-read your 1st post and I agree with what your fitters are planning to do.

 

[king of pipes]

It looks like your installers have it covered providing the walls can take the weight of the wall tiling and the tanking system is fitted and sealed correctly then all should be ok , it looks like a impressive project so no corners should be cut, the prep and first fix is vital to a successful outcome, project manage this one well regular checks and plenty of photos don't put your trust totally in your builder keep checking regularly the standard of work it needs to be A1 . Kop

 

[Ben-gee]

Agree it looks like a nice project.
You cannot have too much structure under that top deck of the bath - it should look like a forest of stud walls under there!
This is your most vulnerable area, I have just done a similar bath - ply, then 12mm hardie then tanked was my choice - you don’t want any movement.

 

[Pgeddon]

It looks like your installers have it covered providing the walls can take the weight of the wall tiling and the tanking system is fitted and sealed correctly then all should be ok , it looks like a impressive project so no corners should be cut, the prep and first fix is vital to a successful outcome, project manage this one well regular checks and plenty of photos don't put your trust totally in your builder keep checking regularly the standard of work it needs to be A1 . Kop

As said in the post at the top, they'd planned to board the areas in blue outline, but they didn't say they'd be tanking any of the bathroom. Just board the blue outlined areas and just tiles direct to plasterboard for the remainder of the room.

I'd hoped that'd be fine, but then i saw the Latest codes of practice of British Standards Institute (BSI) for BS 5385-1 with regards to wet rooms / bathrooms, Link below.

Tanking A Tiled Bathroom Is Now Mandatory…

Bathrooms & Wetroom Must Be Tanked To Comply With British Standards Institute (BSI) for BS 5385-1. Do you need to tank a bathroom? British Building Standards.

www.rubberduckbathrooms.co.uk

In that links it says

"What areas needs Tanking?

A wet area is considered to be any wet-room, bathroom, shower area, steam room or any other location that is subjected to frequent water contact. This would include the walls and floor in a wetroom, walls within a shower cubicle and walls around a bath with a shower."

I find that a little confusing, do they mean the entire has to be tanked for it to be within regs then? or just the vulnerable parts (i.e shower, and raised bath)

 

[Pgeddon]

Tbh there is no real need to tank the wall with the vanity.
I just Re-read your 1st post and I agree with what your fitters are planning to do.

thanks, what about the south wall, where the door is?

 

[ShaunCorbs]

Are they decent brand / you can get spares for them in 10 years ? Eg taps / showers

You use schulter waterproofing and yes else no point fitting them as it’s not water tight

 

[Pgeddon]

Agree it looks like a nice project.
You cannot have too much structure under that top deck of the bath - it should look like a forest of stud walls under there!
This is your most vulnerable area, I have just done a similar bath - ply, then 12mm hardie then tanked was my choice - you don’t want any movement.

Yeah agreed..

Its getting the balance of not safety of mind and finance I guess.

I think the most sensible with respects to above will be to tilebacker board and tank the bath and shower areas. and tank the rest of the room. I guess that could be considered overkill but I'm just thinking now's the time to get it right, I dont want to have to revisit this and if its only an extra few hundred quid for the extra tanking/boarding. It'd be multiples of that if we have to redo the room in future.

 

[king of pipes]

As said in the post at the top, they'd planned to board the areas in blue outline, but they didn't say they'd be tanking any of the bathroom. Just board the blue outlined areas and just tiles direct to plasterboard for the remainder of the room.

I'd hoped that'd be fine, but then i saw the Latest codes of practice of British Standards Institute (BSI) for BS 5385-1 with regards to wet rooms / bathrooms, Link below.

Tanking A Tiled Bathroom Is Now Mandatory…

Bathrooms & Wetroom Must Be Tanked To Comply With British Standards Institute (BSI) for BS 5385-1. Do you need to tank a bathroom? British Building Standards.

www.rubberduckbathrooms.co.uk

In that links it says

"What areas needs Tanking?

A wet area is considered to be any wet-room, bathroom, shower area, steam room or any other location that is subjected to frequent water contact. This would include the walls and floor in a wetroom, walls within a shower cubicle and walls around a bath with a shower."

I find that a little confusing, do they mean the entire has to be tanked for it to be within regs then? or just the vulnerable parts (i.e shower, and raised bath)

All wet areas should have waterproof tile backer boards fitted with all with joints taped and sealed and tanked that's the shower and bath area, the rest I would and use a paint on tanking system and tape up before tiling we also have a UK tiling forum you can log into there you can get more professional advice and help , as said before keep a close eye on the standard of work I haven't been impressed so far regarding the drainage issue you had ,this job needs good highly skilled craftsmen to achieve a very high standard of finish the job deserves . Regards kop

 

[Pgeddon]

All wet areas should have waterproof tile backer boards fitted with all with joints taped and sealed and tanked that's the shower and bath area, the rest I would and use a paint on tanking system and tape up before tiling we also have a UK tiling forum you can log into there you can get more professional advice and help , as said before keep a close eye on the standard of work I haven't been impressed so far regarding the drainage issue you had ,this job needs good highly skilled craftsmen to achieve a very high standard of finish the job deserves . Regards kop

Cheers, it is a different team from the soil pipe to be fair - but its something i'll be keeping an eye on regardless.

Just a quick one - the process for tanking the tile backer boards and tanking is the same right? your message about sounded like it was different? i.e tanking is paint and tape regardless of what you're tanking onto? or have I misunderstood.

 

[Ben-gee]

Tanking is either paint and tape, or (probably better if done correctly) membrane.

 

[Pgeddon]

Tanking is either paint and tape, or (probably better if done correctly) membrane.

ah, can you link me to some membrane?

I was gonna buy 3 tubs of this stuff. :- Mapei AquaDefense Waterproofing Membrane 7.5kg - https://www.NoLinkingToThis/p/mapei-aquadefense-waterproofing-membrane-7-5kg/8531d

it says it's a liquid paint on membrane, are you talking a bout something else?


Also the plumbers aid they're using KERDI boards from Schluter, they look to be waterproof?

 

[ShaunCorbs]

Have a read

https://www.schluter.co.uk/media/schlueter_db_12_1_kerdi_board_uk.pdf

https://www.schluter.co.uk/media/schlueter_db_8_1_kerdi_uk.pdf

 

[king of pipes]

Cheers, it is a different team from the soil pipe to be fair - but its something i'll be keeping an eye on regardless.

Just a quick one - the process for tanking the tile backer boards and tanking is the same right? your message about sounded like it was different? i.e tanking is paint and tape regardless of what you're tanking onto? or have I misunderstood.

As above tanking is paint on and tape this can be applied to plaster board or other boarding to make it more durable and protected from moisture, tile backer boards are insulating foam sandwiched between cement faced reinforced fibre glass for strength and are totally waterproof, the other thing to consider is the weight of tiles and adhesive as the list below , we have a sponsor the wet room store who stock every thing you need to achieve the perfect prep for tiling onto I regularly use their thermopanel .

 

[WillaHolland]

I get your concern about waterproofing your new bathroom, you don't want to end up with a horror story like those on YouTube. From what I can see in the pictures, the bathroom looks impressive and I agree with ShaunCorbs that Schlüter boards are a great option for waterproofing. I would recommend using them throughout the bathroom, especially under the sunken bath and shower cubicle, as Ben-gee pointed out, those are the most vulnerable areas.

 

[SimonG]

I get your concern about waterproofing your new bathroom, you don't want to end up with a horror story like those on YouTube. From what I can see in the pictures, the bathroom looks impressive and I agree with ShaunCorbs that Schlüter boards are a great option for waterproofing. I would recommend using them throughout the bathroom, especially under the sunken bath and shower cubicle, as Ben-gee pointed out, those are the most vulnerable areas.

18 months old, I would imagine it's been long done.