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

I'm going to use moisture-resistant plasterboard for the ceiling of a
shower room in my renovation.

Would Aquapanel be any better for your purposes ?

geraldthehamster wrote:
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

Ive got perfectly standard plasterboard above my showers. No problems.

Unless you deliberately spray the ceiling water generally comes
downwards out of showers....

In article ,
The Natural Philosopher writes:
geraldthehamster wrote:
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

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.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

"Andrew Gabriel" wrote in message
...
In article ,
The Natural Philosopher writes:
geraldthehamster wrote:
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

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.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

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.

On Oct 27, 7:20*pm, The Natural Philosopher wrote:

Ive got perfectly standard plasterboard above my showers. No problems.

Unless you deliberately spray the ceiling water generally comes
downwards out of showers....

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

geraldthehamster wrote:
On Oct 27, 7:20 pm, The Natural Philosopher wrote:

Ive got perfectly standard plasterboard above my showers. No problems.

Unless you deliberately spray the ceiling water generally comes
downwards out of showers....

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

geraldthehamster wrote:
On Oct 27, 7:20 pm, The Natural Philosopher wrote:

Ive got perfectly standard plasterboard above my showers. No problems.

Unless you deliberately spray the ceiling water generally comes
downwards out of showers....

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.


foil backed board then.

Scarcely rocket science.

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?


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.


Regards
Richard

On Oct 27, 7:40*pm, (Andrew Gabriel)
wrote:
In article ,
* * * * The Natural Philosopher writes:



geraldthehamster wrote:
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

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.

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

On 28 Oct, 14:16, wrote:
On Oct 27, 7:40*pm, (Andrew Gabriel)
wrote:





In article ,
* * * * The Natural Philosopher writes:

geraldthehamster wrote:
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

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.

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.


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

On Oct 28, 11:54*am, Rob G
wrote:
geraldthehamster wrote:
On Oct 27, 7:20 pm, The Natural Philosopher wrote:

Ive got perfectly standard plasterboard above my showers. No problems.

Unless you deliberately spray the ceiling water generally comes
downwards out of showers....

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

or a flow switch plus fan with timer, more reliable.


NT

geraldthehamster wrote:
On 28 Oct, 14:16, wrote:
On Oct 27, 7:40 pm, (Andrew Gabriel)
wrote:





In article ,
The Natural Philosopher writes:
geraldthehamster wrote:
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
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.
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.


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 ;-)


Probably, but since all you need for a vapour barrier is cheap foil
backed board, who cares?

Regards
Richard