Cold exterior bathroom wall

bibibobo

Hi, is it ok to just blob standard plasterboard directly onto my bathroom exterior wall blocks using lafarge plasterboard adhesive? The wall is of hollow block construction rendered internally and sealed with PVA. There is no insulation in the wall but i'm not too bothered about that as any insulation is going to take from the size of a small bathroom and surely the plasterboard + air gap will help a little. Since the bathroom is a humid environment is there a risk that this method could cause problems with moisture in the air penetrating painted plasterboard and condensing on the cold exterior wall which could cause a number of problems (mold, plasterboard adhesive unsticking etc)? Would i be better to just put wooden battens 1" thick onto the wall then cover with a multilayer foil insulation then plasterboard taped, jointed and painted? Any thoughts much appreciated.

gsxr1

bibibobo wrote: »

Hi, is it ok to just blob standard plasterboard directly onto my bathroom exterior wall blocks using lafarge plasterboard adhesive? The wall is of hollow block construction rendered internally and sealed with PVA. There is no insulation in the wall but i'm not too bothered about that as any insulation is going to take from the size of a small bathroom and surely the plasterboard + air gap will help a little. Since the bathroom is a humid environment is there a risk that this method could cause problems with moisture in the air penetrating painted plasterboard and condensing on the cold exterior wall which could cause a number of problems (mold, plasterboard adhesive unsticking etc)? Would i be better to just put wooden battens 1" thick onto the wall then cover with a multilayer foil insulation then plasterboard taped, jointed and painted? Any thoughts much appreciated.

I would use 50mm( 2X1 1/2) batons. 400c centers.
50mm kingspan in between.
vapour barrier and 25mm insulated plasterboard. That will make a big difference.

if you are going to bother doing it. do it well.

RKQ

gsxr1 wrote: »

I would use 50mm( 2X1 1/2) batons. 400c centers.
50mm kingspan in between.
vapour barrier and 25mm insulated plasterboard. That will make a big difference.

if you are going to bother doing it. do it well.

I'd agree but if 75mm is too much to loose then definitely go with 50mm( 2X1 1/2) batons. 400c centers 50mm kingspan in between. It will save heat and prevent condensation problems.

Heat in a bathroom is so important, just for your own comfort. It must be cold at the moment!

gsxr1

RKQ wrote: »

I'd agree but if 75mm is too much to loose then definitely go with 50mm( 2X1 1/2) batons. 400c centers 50mm kingspan in between. It will save heat and prevent condensation problems.

Heat in a bathroom is so important, just for your own comfort. It must be cold at the moment!

would it be possible to stick a 50mm insulated slab onto the wall. This would help with cold bridging.

How does the insulation side of the plaster board take to being blobbed?

builditwell

I have to agree with GSXR1 and rkq you hae to put insulation in there. Prior to the bathroom being renovated after even the shortest of showers the water ran down the wall. This was with extractor running. it was freezing to the touch. i thought about incresaing the rad size but now its actually turned down half way.

I put 50mm warmboard onto exsisting external wall after rendering and vapour barrier and this has made a huge difference. I lost 2 inches in the length but this is nothing compared to the now comfortable room. It used to like an ice box. The wife almost rented it out for cold storage.

Regards
Builditwell

bibibobo

Think I will go ahead with the 50mm kingspan, sure i've a spare sheet in the attic. Only hassle with doing this job is the rad on the external wall having to be moved 2.5" out as i'll need to dig up the floor and shorten pipes - pain in the ass but sure long term it'll be worth it. Was thinking of not getting it skimmed coated and just doing a tape and joint skim instead to save money, it may not look the best.

gsxr1

bibibobo wrote: »

Think I will go ahead with the 50mm kingspan, sure i've a spare sheet in the attic. Only hassle with doing this job is the rad on the external wall having to be moved 2.5" out as i'll need to dig up the floor and shorten pipes - pain in the ass but sure long term it'll be worth it. Was thinking of not getting it skimmed coated and just doing a tape and joint skim instead to save money, it may not look the best.

taped wall can look perfect. Depending on the effort.

But you should buy Green board instead of ordinary plasterboard if you intend to tape . It is a few pound more but is better for moister resistance.