I'm going to use moisture-resistant plasterboard for the ceiling of a shower room in my renovation. This will be screwed under 3x2 ceiling joists, with rock wool above. How moisture-resistant is it, and would I be wise also to install a vapour barrier? The roof space above the ceilings is ventilated (soffit vents and vented ridge tiles).
If relevant, this is the first floor of a dormer bungalow, so the roof space left above the ceilings is pretty small.
Regards Richard
Would Aquapanel be any better for your purposes ?
Ive got perfectly standard plasterboard above my showers. No problems.
Unless you deliberately spray the ceiling water generally comes downwards out of showers....
That was my thought too. Actually, the ceiling in one shower does get wet sometimes; if you turn that shower on too much, water blows past all the seals in the showhead and soaks the whole bathroom. Still, the ceiling hasn't come to any harm -- it usually just rights off a toilet roll on the other side of the room.
Even if it isn't skimmed, two or three coats of vinyl silk emulsion should waterproof it sufficiently against modest spray / condensation. Might be worth using the mould resistant paint made for kitchens and bathrooms.
It's not direct spray from the shower that's the issue, it's the water vapour in the air, which is why we have vapour barriers: to prevent water vapour penetrating into a cold space and condensing within the roof structure. Two people sleeping in a bedroom can generate enough of that, let alone a shower.
My roof space is ventilated, and there will be extraction in the shower room, so I'm not anticipating a problem. Having said that, I've just fitted a 25mm sheet of foil-backed Kingspan to the ceiling joists before installing the PB, as part of my insulation regime, so I'd say that was both belt and braces taken care of.
None of which answers my original question ;-) Just how moisure- resistant is moisture-resistant PB?
Regards Richard
I'm going to dodge the question too as I've never heard of this material. But I'm dodging it to join in with those above who are saying that it isn't necessary; I built my current shower area some 20 years ago with a plasterboard ceiling, a membrane above it and then insulation - roof space above. No problems just as all the others haven't had any.
Concern about water vapour - then make sure there isn't any lingering by putting in a humidity switched extractor. Even better get one which has a pull switch on it to and it can be switched on manually as well - probably still available for £25 or so off Ebay.
Rob
Me too. Both our bathrooms have perfectly ordinary plasterboard walls &/or ceilings, and I've never noticed any problems. They're both painted with "bathroom & kitchen" paint.
foil backed board then.
Scarcely rocket science.
well moisture to me means water droplets in suspension, or in liquid form adsorbed or absorbed into a matrix.
You are talking vapour barrier, which is a different thing.
The short answer is, if painted with emulsion, pretty good,.
I wash emulsion painted plasterboard walls with no bad effects. Its when water gets behind the surface that it goes pear shaped.
All this aquapanel stuff is predicated on the assumption that water WILL get behind the surface coating. That as far as I am concerned means the whole design is wrong.
Shower ceilings can get wet every time, due to steam & condensation. Standard PB seems happy enough in this situation, as long as the room dries out after use.
NT
It's interesting that several people are considering this in terms of damage to the ceiling, which isn't the issue. The issue is whether water vapour is penetrating the PB into the roof space - which it will, with standard PB without a vapour barrier. Not that this is likely to be a problem, provided the roof space is ventilated.I wondered whether moisture-resistant PB would remove the theoretical need for a vapour barrier - which nobody seems to know ;-)
Regards Richard
or a flow switch plus fan with timer, more reliable.
NT
Probably, but since all you need for a vapour barrier is cheap foil backed board, who cares?
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.