Condensation

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pilch

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Although I am a joiner by trade, my query is very much from the perspective of a plastering DIY'er. Having done a number of smaller plastering jobs I have the deepest admiration for the professionals. It takes me ages, it exhausts me and my finish is only so-so.
I insulated the walls of the top floor of our house with 60mm foil-backed insulated plasterboard. The house is one end of a 1960's 2-storey solid stone barn conversion, upside-down house with a large open-plan kitchen/lounge/diner upstairs. Although I say so myself I did a pretty good job... perfectly plumb and level with invisibly skimming joints, and.... the thermal gain is astonishing.
The flat ceiling was already insulated but I seem to get some cold-spotting along the a 4 to 6 inch strip along the gable-end ceiling edge. It shows as darkening of the white vinyl-emulsion paint caused by the ambient moisture condensing on it.
My analysis is that the ceiling edge is drawing cold from where it touches the rendered and plastered stonework, and that maybe what I should have done before I insulated the walls was hack-off 30mm or so of ceiling along this gable-end edge... maybe filling with the same gun-foam I stuck the boards on with.

Anyone had, or seen, this problem. If so... what easy-fix cure can they recommend.
The room is well ventilated with powerful kitchen extraction... when she switches it on.
All I can think of doing is applying coving, or using some type of ant-condensation paint.
 
pilch said:
Although I am a joiner by trade, my query is very much from the perspective of a plastering DIY'er. Having done a number of smaller plastering jobs I have the deepest admiration for the professionals. It takes me ages, it exhausts me and my finish is only so-so.
I insulated the walls of the top floor of our house with 60mm foil-backed insulated plasterboard. The house is one end of a 1960's 2-storey solid stone barn conversion, upside-down house with a large open-plan kitchen/lounge/diner upstairs. Although I say so myself I did a pretty good job... perfectly plumb and level with invisibly skimming joints, and.... the thermal gain is astonishing.
The flat ceiling was already insulated but I seem to get some cold-spotting along the a 4 to 6 inch strip along the gable-end ceiling edge. It shows as darkening of the white vinyl-emulsion paint caused by the ambient moisture condensing on it.
My analysis is that the ceiling edge is drawing cold from where it touches the rendered and plastered stonework, and that maybe what I should have done before I insulated the walls was hack-off 30mm or so of ceiling along this gable-end edge... maybe filling with the same gun-foam I stuck the boards on with.

Anyone had, or seen, this problem. If so... what easy-fix cure can they recommend.
The room is well ventilated with powerful kitchen extraction... when she switches it on.
All I can think of doing is applying coving, or using some type of ant-condensation paint.
Click to expand...
mould paint.

Moisture is going to condensate (is that a word?) in the coldest spot in the house.

Save yourself the agg of fighting a losing battle and apply zinsser mould paint.

You'll still get the condensation but no mould. It's wipe clean too so won't absorb any moisture.
 
Stevieo said:
mould paint.

Moisture is going to condensate (is that a word?) in the coldest spot in the house.

Save yourself the agg of fighting a losing battle and apply zinsser mould paint.

You'll still get the condensation but no mould. It's wipe clean too so won't absorb any moisture.
Click to expand...
We don't get mould, just a little darkening from the condensed moisture absorbing into plaster through the matt vinyl emulsion. One of my possible solutions, and certainly the simplest, was an anti-condensation paint... which may have very similar properties to the Zinsser anti-mold paint mentioned.
I am assuming that the cold surfaces that are attracting condensation and absorbing it, just need a non-permeable painted on barrier, which although won't prevent condensation, will prevent absorption and therefore that slight damp-darkening.
How about this stuff?
https://www.permagard.co.uk/anti-condensation-paint
 
pilch said:
We don't get mould, just a little darkening from the condensed moisture absorbing into plaster through the matt vinyl emulsion. One of my possible solutions, and certainly the simplest, was an anti-condensation paint... which may have very similar properties to the Zinsser anti-mold paint mentioned.
I am assuming that the cold surfaces that are attracting condensation and absorbing it, just need a non-permeable painted on barrier, which although won't prevent condensation, will prevent absorption and therefore that slight damp-darkening.
How about this stuff?
https://www.permagard.co.uk/anti-condensation-paint
Click to expand...
Seems to me that if you prevent condensation in one place it'll pop up somewhere else. That moisture is going to land up somewhere. Next place you'll find it is behind furniture that's close to walls.

Do yourself a favour and dry the area thoroughly. Part of the protection mould paint offers is its non permeability. That means that it will lock moisture in as well as out and might prevent what's behind it drying after application
 
Moisture will only condense on cold surfaces. Remove the cold surfaces surfaces and there is no condensation. All my walls, window reveals, and ceiling are insulated, the windows are double-glazed, and the only cold spot is that 4" strip along the gable wall... which I cannot remove.
There has never been visible surface condensation on that strip, just a darkening because the paint and plaster are porous, but I will be drying the area 100% with heat and a dehumidifier before doing any remedial work. I do understand that whatever painted treatment I decide to use will be non-porous... which will prevent re-absorption from any moisture-laden ambient air in the room... but the Permaguard seems to also promise another function which somehow raises the temperature of the surface and thereby prevents/minimizes further condensation. Magic stuff if true.
 
pilch said:
Moisture will only condense on cold surfaces. Remove the cold surfaces surfaces and there is no condensation. All my walls, window reveals, and ceiling are insulated, the windows are double-glazed, and the only cold spot is that 4" strip along the gable wall... which I cannot remove.
There has never been visible surface condensation on that strip, just a darkening because the paint and plaster are porous, but I will be drying the area 100% with heat and a dehumidifier before doing any remedial work. I do understand that whatever painted treatment I decide to use will be non-porous... which will prevent re-absorption from any moisture-laden ambient air in the room... but the Permaguard seems to also promise another function which somehow raises the temperature of the surface and thereby prevents/minimizes further condensation. Magic stuff if true.
Click to expand...
Why the fûck did you bother asking for advice if you're just going to argue that your idea is better?

Go ahead and use the permaguard.
 
From that response, Stevieo, I gather you have nothing constructive or informative to add to this topic.
I'll repeat... the walls are insulated, even behind furniture, so do not attract condensation.
Moist air will only condense on cold surfaces. That's basic physics.
My own researches have provided me with one possible solution that seems less than ideal but maybe worth a try.
But I had hoped to have the forum suggest solutions I hadn't thought of, or maybe even someone saying they'd had the same problem and how they tried to deal with it.
Have a good life Stevieo.
 
pilch said:
From that response, Stevieo, I gather you have nothing constructive or informative to add to this topic.
I'll repeat... the walls are insulated, even behind furniture, so do not attract condensation.
Moist air will only condense on cold surfaces. That's basic physics.
My own researches have provided me with one possible solution that seems less than ideal but maybe worth a try.
But I had hoped to have the forum suggest solutions I hadn't thought of, or maybe even someone saying they'd had the same problem and how they tried to deal with it.
Have a good life Stevieo.
Click to expand...
I have had the same problem renovating a couple of dozen shitty old apartments in freezing rainy Donegal.

And been back between tenants so know what everything looks like after a year or two.
You asked for advice based on experience and there it is.

You haven't had mould YET.

Your paint offers to add a little extra insulation to a cold spot. If it works then your condensation will appear somewhere else.
 
If you'd had the same problem then what, if any, solution was found.
Re YET... 7 years and no mold.
Re condensation will appear somewhere else... not in any world where the laws of physics apply and water vapour condenses only onto cold surfaces. There IS a complex interaction between humidity and temperature whereby it is technically possible for condensation to form on any surface if humidity is high enough, but we are not really talking sauna or Turkish Bath levels here.
 
pilch said:
From that response, Stevieo, I gather you have nothing constructive or informative to add to this topic.
I'll repeat... the walls are insulated, even behind furniture, so do not attract condensation.
Moist air will only condense on cold surfaces. That's basic physics.
My own researches have provided me with one possible solution that seems less than ideal but maybe worth a try.
But I had hoped to have the forum suggest solutions I hadn't thought of, or maybe even someone saying they'd had the same problem and how they tried to deal with it.
Have a good life Stevieo.
Click to expand...
Sort humidity out @

The end .
 
pilch said:
Although I am a joiner by trade, my query is very much from the perspective of a plastering DIY'er. Having done a number of smaller plastering jobs I have the deepest admiration for the professionals. It takes me ages, it exhausts me and my finish is only so-so.
I insulated the walls of the top floor of our house with 60mm foil-backed insulated plasterboard. The house is one end of a 1960's 2-storey solid stone barn conversion, upside-down house with a large open-plan kitchen/lounge/diner upstairs. Although I say so myself I did a pretty good job... perfectly plumb and level with invisibly skimming joints, and.... the thermal gain is astonishing.
The flat ceiling was already insulated but I seem to get some cold-spotting along the a 4 to 6 inch strip along the gable-end ceiling edge. It shows as darkening of the white vinyl-emulsion paint caused by the ambient moisture condensing on it.
My analysis is that the ceiling edge is drawing cold from where it touches the rendered and plastered stonework, and that maybe what I should have done before I insulated the walls was hack-off 30mm or so of ceiling along this gable-end edge... maybe filling with the same gun-foam I stuck the boards on with.

Anyone had, or seen, this problem. If so... what easy-fix cure can they recommend.
The room is well ventilated with powerful kitchen extraction... when she switches it on.
All I can think of doing is applying coving, or using some type of ant-condensation paint.
Click to expand...
If there is a loft is the ceiling/loft insulation taken right up to the gable wall, if its is you could clearly get this problem.

you said "flat ceiling", i am assuming you didnt mean flat roof i.e. no loft.

Is there an uninsulated RSJ or similar in the loft running that way which would also be cold. I think it is most likely an issue with insulation or a heat conducting path through from the external face of the gable wall.
 
Adding insulation or using anti-condensation paint along the gable-end ceiling edge should help alleviate the cold-spotting issue and improve the comfort of the room. If you're unsure about which solution would be best for your specific situation, consulting with a professional plasterer or builder could provide valuable insight and guidance.
 
tacomamold said:
Adding insulation or using anti-condensation paint along the gable-end ceiling edge should help alleviate the cold-spotting issue and improve the comfort of the room. If you're unsure about which solution would be best for your specific situation, consulting with a professional plasterer or builder could provide valuable insight and guidance.
Click to expand...
Wasting your time —they are all fuxin clowns

Post it in here /::: I will sort it…..
 
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