help needed CONDENSATION

paulbhoy

hi wonder can anyone help or advise me ????
i have had a bad problem with condensation in my ensuite so much so that i have had to remove tiles plaster board on stud wall was rotten so took that out......plasterboard on external wall was rotten to so remove that to find that there was no vapour barrier only insulation slabs between battens.....????? is this the correct construction method?????? or is this the reason for my condensation problems

Poor Uncle Tom

Not a good idea to have plasterboard behind tiles on shower walls, as you are depending on the tile grout to keep moisture away from the soft chalky board material. WBP is usually used in these areas.

A vapour barrier should have been incorporated in the outer wall make up. It sounds as though you have a mixture of shower water soaking through your grout to the plasterboard behind and possibly not enough ventilation in the ensuite.

Check the shower tray to wall seal as well.

paulbhoy

cheers tom
There was a bad seal at the shower to the wall but i repaired that......when i removed the tiles the area of plasterboard around the water connection for the shower was very moist too...... the builder used normal 12.5 mm plasterboard behind the shower area....... sorry for my ignorance but what is a WBP that you speak of.
As regards the vapour barrier it looks to me as if they have concrete block walls battened out with treated timber but instaed of having rockwool then the plastic sheeting then plasterboard all that is there is xtratherm foil slabs screwed into the timber and plasterboard on top is this correct ????

oraiste

Tom is referring to WBP Plywood (Weather and Boil Proof Plywood). It is considered the standard substrate used for tiling in shower areas. Standard plasterboard is not suitable and should be replaced.

There are specialist plasterboards available for tiling, such as Gyproc Moisture Resistant Plasterboard (plasterboard with water repellent additives in the core, encased in a special green paper liner. Suitable as a base for ceramic tiling in wet use areas).

There are some good general tiling guides to be found on the net:

http://www.originalstyle.com/technical_guides.htm
http://www.tiles.org.uk/help/tileitright.pdf

Poor Uncle Tom

paulbhoy wrote: »

...the vapour barrier it looks to me as if they have concrete block walls battened out with treated timber but instaed of having rockwool then the plastic sheeting then plasterboard all that is there is xtratherm foil slabs screwed into the timber and plasterboard on top is this correct ????

Not quite paul, any contact with the blockwork should be through DPC (damp proof course) 1000 gauge preferably, imo. The vapour check layer should be in one continuous layer directly on the inner (room) side of the insulation. This is to prevent the room vapours/moisture getting through or passed the insulation to the cold outer surfaces, or worse in the centre of the cold outer materials causing interstitial condensation, and then freezing.

paulbhoy

so basically the builder who built my house has not built it correctly ?????
do you know of any websites or agencies that might be able to help me word an email to the builder to complain about how it is built as i dont feel i should have to foot the bill for repairing this problem !!!!

Poor Uncle Tom

You need to talk to your solicitor to see if it is appropriate to apportion blame in this case, I'm not a solicitor so I won't comment.

davgtrek

as an aside for your construction problems a factor that does not help in 90% of spec housing is the extract fan. they are usually absolutely crap at extracting and literally end up ineffective after a year or so.

get your backing to tiles right and waterproofing but install a decent wall/ceiling extract fan.

go with a VENT AXIA or an EXPELAIR surface mounted centrifugal fan with timer over run. they are strong ( which means quiet as dont need to operate at max to suffice ) and reliable.

I have some damp issues in my own house even though the shower area was constructed properly. I have come to the decision that tiling in shower areas is a bad idea. grout is ineffective after a while and almost definately water will penetrate at some stage. especially with powershowers being common place.

also make sure that the room is warm prior to showering. have the radiator timed to come on 30 minutes before expectant showering. as if the room is warm then you wont get as much condensation on the surfaces of tiles and the fan will suck most of it out.

P

davethebuilder

paulbhoy wrote: »

so basically the builder who built my house has not built it correctly ?????
do you know of any websites or agencies that might be able to help me word an email to the builder to complain about how it is built as i dont feel i should have to foot the bill for repairing this problem !!!!

always worth a call to homebond if the builder was regisered - they will advise and maybe help on this

bauderline

I seen a thread some time ago that indicated cement board was a better option for show areas...

Any comment on that one ?

P.

davethebuilder

bauderline wrote: »

I seen a thread some time ago that indicated cement board was a better option for show areas...

Any comment on that one ?

P.

its a good product, seen it used in hotels and worked reasonably well, but they put pvc sheets against it rather then tiling, you really need to tank with seamless materials like spray on polyurethane or have the pvc sheets v.v.v well installed to be sure of no leakage, tiles have grout line and they will leak through no matter what you do, cement board is usually good enough to withstand the moisture in normal residential jobs through the grout, if its a larger job tank it with polyurethane (rhinolinings is the one i have seen in ireland) and you will be 100% covered (even if its just plasterboard behind), its not cheap but the best out there.

RKQ

I have cement board in my shower - its formed from cement board. Its fully tiled - walls and floor. Cement board is excellent for tiling.

Its also got good sound proofing qualities due to it dense structure which is also very good for retaining the heat of electric underfloor heating.

Plasterboard in a bathroom is never a good idea. Plasterboard within the area of a shower tray is crazy!

Poor ventilation and a leaky shower tray probably caused alot of damage.