I have a ceiling area which is very prone to condensation and mould
problems - in this picture it's the funny-looking arrowed area
(characterful, as the estate agents would put it) which protrudes
downwards into the room, and is very cold due to the close proximity of
the valley gutter above it.

http://img.photojerk.com/axV49uc7j.JPG

There's not really any way of getting any more insulation above the
ceiling, and unless I start cladding the ceiling with polystyrene
sheeting (which I really don't want to do), so I'm trying to prevent the
recurrence of mould.

This is in a rented-out house, and it's not easy (ie impossible!) to
educate the tenants about ventilating the place properly. I'm between
tenants right now, and have just cleaned away all the black gunk using
proprietary bleach-based mildew remover which worked a treat.

Fiinally, the question!

I want to repaint the ceiling now, but what best to use? Do these
bathroom/kitchen paints contain fungicide to prevent regrowth? Browsing
at B&Q just now, it didn't seem so. I came away with some "fungicidal
wash" which you can use pre-painting - will that do the trick (insofar
as anything will?) if I apply it prior to ordinary emulsion? I've heard
about anti-condensation paint but couldn't find any at B&Q - or is that
just the kitchen/bathroom stuff?

Any advice appreciated...

David

In article ,
Lobster writes:
I have a ceiling area which is very prone to condensation and mould
problems - in this picture it's the funny-looking arrowed area
(characterful, as the estate agents would put it) which protrudes
downwards into the room, and is very cold due to the close proximity of
the valley gutter above it.

http://img.photojerk.com/axV49uc7j.JPG

There's not really any way of getting any more insulation above the

Does that imply there is some? What is it?
Even just an inch thick sheet of cellotex would stop this.

If there is no gap, you can get cellotex-backed plasterboard,
and replacing that part of the ceiling with it would work well
(or a 1" sheet of ordinary cellotex behind standard plasterboard).

Nothing you paint on it will stop condensation when it's cold
and below the dew point.

--
Andrew Gabriel

Andrew Gabriel wrote:
In article ,
Lobster writes:
I have a ceiling area which is very prone to condensation and mould
problems - in this picture it's the funny-looking arrowed area
(characterful, as the estate agents would put it) which protrudes
downwards into the room, and is very cold due to the close proximity of
the valley gutter above it.

http://img.photojerk.com/axV49uc7j.JPG

There's not really any way of getting any more insulation above the

Does that imply there is some? What is it?
Even just an inch thick sheet of cellotex would stop this.

If there is no gap, you can get cellotex-backed plasterboard,
and replacing that part of the ceiling with it would work well
(or a 1" sheet of ordinary cellotex behind standard plasterboard).

Nothing you paint on it will stop condensation when it's cold
and below the dew point.


AFAIK anti condensation paints contain microspheres. Maybe if the coat
was an inch thick it might help

Lobster wrote:

I have a ceiling area which is very prone to condensation and mould
problems - in this picture it's the funny-looking arrowed area
(characterful, as the estate agents would put it) which protrudes
downwards into the room, and is very cold due to the close proximity of
the valley gutter above it.

http://img.photojerk.com/axV49uc7j.JPG

There's not really any way of getting any more insulation above the
ceiling, and unless I start cladding the ceiling with polystyrene
sheeting (which I really don't want to do), so I'm trying to prevent the
recurrence of mould.

This is in a rented-out house, and it's not easy (ie impossible!) to
educate the tenants about ventilating the place properly. I'm between
tenants right now, and have just cleaned away all the black gunk using
proprietary bleach-based mildew remover which worked a treat.

Fiinally, the question!

I want to repaint the ceiling now, but what best to use? Do these
bathroom/kitchen paints contain fungicide to prevent regrowth? Browsing
at B&Q just now, it didn't seem so. I came away with some "fungicidal
wash" which you can use pre-painting - will that do the trick (insofar
as anything will?) if I apply it prior to ordinary emulsion? I've heard
about anti-condensation paint but couldn't find any at B&Q - or is that
just the kitchen/bathroom stuff?

Any advice appreciated...

David

http://wiki.diyfaq.org.uk/index.php?...esistant_Paint


Even if you had to put an inch of insulation on the surface, a stepped
patch will probably look as good as mould, or better.

Usually a waste of time explaining things, most tenants couldnt give a
toss. As far as theyre concerned its your problem and doesnt concern
them.

The other approach os to reduce the interior RH. This might take
nothing more than a sheet of paper suggesting ways to save money,
including turning the ring right down and using a lid. And how to make
your room fresh by airing it in the am etc. Can sometimes work.


NT

wrote:
Lobster wrote:

There's not really any way of getting any more insulation above the
ceiling, and unless I start cladding the ceiling with polystyrene
sheeting (which I really don't want to do), so I'm trying to
prevent the recurrence of mould.

In response to Andrew - the trouble is that not only is there this
valley above, but the roof has a very shallow pitch. When I originally
refurbished the place 2-3 years ago I put about 9" of Rockwool into the
roof space, but that area was a nightma I ended up lying down full
length and poking the stuff in using a stick, also trying to maintain
adequate ventilation up there. I think the only way of sorting it
properly would be to remove and rebuild the valley gutter or to pull the
ceiling down and start again, neither of which appeals!

I want to repaint the ceiling now, but what best to use? Do these
bathroom/kitchen paints contain fungicide to prevent regrowth?
Browsing at B&Q just now, it didn't seem so. I came away with some
"fungicidal wash" which you can use pre-painting - will that do the
trick (insofar as anything will?) if I apply it prior to ordinary
emulsion? I've heard about anti-condensation paint but couldn't
find any at B&Q - or is that just the kitchen/bathroom stuff?

http://wiki.diyfaq.org.uk/index.php?...esistant_Paint

Adding aspirin to the paint - that's an interesting idea! Wouldn't an
antibiotic like penicillin work better though (thinking of Alexander
Fleming and his bread mould)? Having said that, the mould is definitely
only the surface as I've been able to clean it away completely (it's
also on glass and uPVC window frames) - wouldn't a drug in the paint
only act if the mould was *within* the interstices of the paint?
+
Usually a waste of time explaining things, most tenants couldnt give
a toss. As far as theyre concerned its your problem and doesnt
concern them.

Well yes, as I said below. Typically they tell you there's 'damp' - ie
meaning leaking from outside - and it's hard to convince them that the
reason I'm not employing armies of roofers etc is not because I'm a
tightwad, it's because I know full well there's no leak to cure!

This is in a rented-out house, and it's not easy (ie impossible!)
to educate the tenants about ventilating the place properly.

The other approach os to reduce the interior RH.

Mm. I tried replacing the bathroom extractor fan with a
humidistat-controlled model, and suggested they routinely left the
upstairs doors open during the day to let it do its stuff, but I suspect
they didn't. Bathroom is fine and dry though, with no reccurrence of
the mouldy silicone I replaced at the time!

I wondered about providing a dehumidifier, but rejected that on the
grounds that they'd be unlikely to use it anyway due to the running costs.

David

Lobster wrote:
wrote:
Lobster wrote:

There's not really any way of getting any more insulation above the
ceiling, and unless I start cladding the ceiling with polystyrene
sheeting (which I really don't want to do), so I'm trying to
prevent the recurrence of mould.

In response to Andrew - the trouble is that not only is there this
valley above, but the roof has a very shallow pitch. When I originally
refurbished the place 2-3 years ago I put about 9" of Rockwool into the
roof space, but that area was a nightma I ended up lying down full
length and poking the stuff in using a stick, also trying to maintain
adequate ventilation up there. I think the only way of sorting it
properly would be to remove and rebuild the valley gutter or to pull the
ceiling down and start again, neither of which appeals!

If youre getting condensation despite 9" of insulation, RH is the
problem rather than inadequate insulation.


I want to repaint the ceiling now, but what best to use? Do these
bathroom/kitchen paints contain fungicide to prevent regrowth?
Browsing at B&Q just now, it didn't seem so. I came away with some
"fungicidal wash" which you can use pre-painting - will that do the
trick (insofar as anything will?) if I apply it prior to ordinary
emulsion? I've heard about anti-condensation paint but couldn't
find any at B&Q - or is that just the kitchen/bathroom stuff?

http://wiki.diyfaq.org.uk/index.php?...esistant_Paint

Adding aspirin to the paint - that's an interesting idea! Wouldn't an
antibiotic like penicillin work better though (thinking of Alexander
Fleming and his bread mould)?

Penicillin, like any antibiotic, will only kill some bacteria. It
doesnt affect mould at all.


Having said that, the mould is definitely
only the surface as I've been able to clean it away completely (it's
also on glass and uPVC window frames)

.... more evidence you've got an RH problem

- wouldn't a drug in the paint
only act if the mould was *within* the interstices of the paint?

The salicylic acid formed is water soluble to some extent. The paint is
not a perfect vapour barrier. Hence salicylic ends up on the surface as
well as within the paint. I tried it and it worked well.

+
Usually a waste of time explaining things, most tenants couldnt give
a toss. As far as theyre concerned its your problem and doesnt
concern them.

Well yes, as I said below. Typically they tell you there's 'damp' - ie
meaning leaking from outside - and it's hard to convince them that the
reason I'm not employing armies of roofers etc is not because I'm a
tightwad, it's because I know full well there's no leak to cure!

yes, I think educating tenants how to solve what they see as your
problem is going nowhere. Theres always a reason theyre tenants.

This is in a rented-out house, and it's not easy (ie impossible!)
to educate the tenants about ventilating the place properly.

The other approach os to reduce the interior RH.

Mm. I tried replacing the bathroom extractor fan with a
humidistat-controlled model, and suggested they routinely left the
upstairs doors open during the day to let it do its stuff, but I suspect
they didn't. Bathroom is fine and dry though, with no reccurrence of
the mouldy silicone I replaced at the time!

If the door isnt airtight it'll work even with it shut, although
leaving the door shut is a daft way to run a bathroom really. If you
add a weight/pulley or spring system and suitable catch type, the door
would stay open when room unused.


I wondered about providing a dehumidifier, but rejected that on the
grounds that they'd be unlikely to use it anyway due to the running costs.

So don't give them the choice. Wire it in. Its perfectly reasonable to
provide fixed equipment to counter their mismanagement, since its
necessary for health.

Tenants can counter any active system if they choose, but usually they
dont bother.

The other approach is to have in writing their obligation to air the
bedroom in the morning, leave the bathroom door open etc, and if mould
occurs due to failure to do this you can writtenly remind them that
they would be responsible for damage caused by their breach of
contract, reminding them politely to do their required bit.

Explaining they have a choice between living with mould and no mould,
depending on their actions, sometimes works.


NT

wrote:
Lobster wrote:
wrote:
Lobster wrote:

There's not really any way of getting any more insulation above the
ceiling, and unless I start cladding the ceiling with polystyrene
sheeting (which I really don't want to do), so I'm trying to
prevent the recurrence of mould.

In response to Andrew - the trouble is that not only is there this
valley above, but the roof has a very shallow pitch. When I originally
refurbished the place 2-3 years ago I put about 9" of Rockwool into the
roof space, but that area was a nightma I ended up lying down full
length and poking the stuff in using a stick, also trying to maintain
adequate ventilation up there. I think the only way of sorting it
properly would be to remove and rebuild the valley gutter or to pull the
ceiling down and start again, neither of which appeals!

If youre getting condensation despite 9" of insulation, RH is the
problem rather than inadequate insulation.

No the 9" is over the main roof area; specifically under the
inaccessible valley gutter bit there will be bugger all.

I want to repaint the ceiling now, but what best to use? Do these
bathroom/kitchen paints contain fungicide to prevent regrowth?
Browsing at B&Q just now, it didn't seem so. I came away with some
"fungicidal wash" which you can use pre-painting - will that do the
trick (insofar as anything will?) if I apply it prior to ordinary
emulsion? I've heard about anti-condensation paint but couldn't
find any at B&Q - or is that just the kitchen/bathroom stuff?

http://wiki.diyfaq.org.uk/index.php?...esistant_Paint

Adding aspirin to the paint - that's an interesting idea! Wouldn't an
antibiotic like penicillin work better though (thinking of Alexander
Fleming and his bread mould)?

Penicillin, like any antibiotic, will only kill some bacteria. It
doesnt affect mould at all.

Right, I was getting muddled - Flemimg found that mould *produced*
penicillin, which killed bacteria, didn't he.

Before I nip down to Sainsbury's, is there evidence other than your
experience that aspirin kills mould, though?

If the door isnt airtight it'll work even with it shut, although
leaving the door shut is a daft way to run a bathroom really. If you
add a weight/pulley or spring system and suitable catch type, the door
would stay open when room unused.

That idea's a distict possibility!

I wondered about providing a dehumidifier, but rejected that on the
grounds that they'd be unlikely to use it anyway due to the running costs.

So don't give them the choice. Wire it in. Its perfectly reasonable to
provide fixed equipment to counter their mismanagement, since its
necessary for health.

How could that be done in a way which they'd be unable to simply bypass,
though? (ie using the off switch) once they realise what the running
costs are!

The other approach is to have in writing their obligation to air the
bedroom in the morning, leave the bathroom door open etc, and if mould
occurs due to failure to do this you can writtenly remind them that
they would be responsible for damage caused by their breach of
contract, reminding them politely to do their required bit.

I think I will, before the next ones move in.

David

Would a vent in the door help?

Lobster wrote:
wrote:
Lobster wrote:
wrote:
Lobster wrote:

If youre getting condensation despite 9" of insulation, RH is the
problem rather than inadequate insulation.

No the 9" is over the main roof area; specifically under the
inaccessible valley gutter bit there will be bugger all.

Oh i see. Well, you need insulation. Why not make a feature of surface
applied insulation. 2 sheets of half inch, one smaller than the other,
like a shallow pedestal upside down, and a light fitting in the middle
or something. Or remove the PB and fit whatever insulation you can.
Dunno. But somehow you need to deal with it, as paint wont stop the
damp and that'll ruin things anyway.


Before I nip down to Sainsbury's, is there evidence other than your
experience that aspirin kills mould, though?

Aspirin reacts with water to produce salicylic acid, thats the active
ingredient. Google away. Add a pinch of copper suphate from the chemist
as well and you've got more mould kill power. Go easy on the cu though,
its not white.

If the door isnt airtight it'll work even with it shut, although
leaving the door shut is a daft way to run a bathroom really. If you
add a weight/pulley or spring system and suitable catch type, the door
would stay open when room unused.

That idea's a distict possibility!

I wondered about providing a dehumidifier, but rejected that on the
grounds that they'd be unlikely to use it anyway due to the running costs.

So don't give them the choice. Wire it in. Its perfectly reasonable to
provide fixed equipment to counter their mismanagement, since its
necessary for health.

How could that be done in a way which they'd be unable to simply bypass,
though? (ie using the off switch) once they realise what the running
costs are!

no off switch, no plug. Not 'ard. Also the run costs are quite low for
a dehumid, you're talking about 200w only on for a fraction of the
time, and on in winter only.


The other approach is to have in writing their obligation to air the
bedroom in the morning, leave the bathroom door open etc, and if mould
occurs due to failure to do this you can writtenly remind them that
they would be responsible for damage caused by their breach of
contract, reminding them politely to do their required bit.

I think I will, before the next ones move in.

David


NT