Painting damp areas

[anthony12uk]

Think we have damp issues in some specific areas as we had a gypsum skim plaster a month ago and they are still not dry. They are slowly drying out now we have a dehumidifier.
Are we better off painting a damp proof/ seal paint of some kind on the fresh plaster, or a breathable clay paint so that the moisture can escape?

 

[Lacan07]

Think we have damp issues in some specific areas as we had a gypsum skim plaster a month ago and they are still not dry. They are slowly drying out now we have a dehumidifier.
Are we better off painting a damp proof/ seal paint of some kind on the fresh plaster, or a breathable clay paint so that the moisture can escape?

That depends on what the source of the moisture is, is the plaster still drying or have you got issues within the fabric of the house? Its always better to address the cause of moisture rather than try and cover it up.

There's no point painting gypsum plaster with expensive, breathable clay paint, its a waste of money.

 

[Stevers]

Gypsum plaster can succumb to damp and salts and become hygroscopic, after which things go very rapidly downhill. A skim of gypsum over lime should be viewed as something that you might get away with rather than good practice for old houses built without DPCs and cavities. The gypsum plaster used over the cementitious tanking in my basement never did dry out, and that was the clue that all was not well.

Most of us here have spent too much time we'll never get back, removing gypsum plaster when it's quite obviously failed.

 

[anthony12uk]

That depends on what the source of the moisture is, is the plaster still drying or have you got issues within the fabric of the house? Its always better to address the cause of moisture rather than try and cover it up.

There's no point painting gypsum plaster with expensive, breathable clay paint, its a waste of money.

There are moisture issues with the kitchen, which is completely tiled from top to bottom with no ventilation/ cooker hood in the room. The wall we want to paint borders the kitchen. The cupboards in there are semi-rotten due to the moisture and need to be replaced, but we just moved in and are saving to have the kitchen redone. We will get a cooker hood installed first which I hope will help the moisture build up significantly. I hope removing the tiles will help with the moisture issue as I assume that moisture cannot get out on that side of the wall.
We panicked at plaster coming off the wall when we first moved in and had a gypsum skim - which I now really regret and wish we had not done but it is too late to change now.
We just got a dehumidifier which is helping a lot.

 

[Lacan07]

There are moisture issues with the kitchen, which is completely tiled from top to bottom with no ventilation/ cooker hood in the room. The wall we want to paint borders the kitchen. The cupboards in there are semi-rotten due to the moisture and need to be replaced, but we just moved in and are saving to have the kitchen redone. We will get a cooker hood installed first which I hope will help the moisture build up significantly. I hope removing the tiles will help with the moisture issue as I assume that moisture cannot get out on that side of the wall.
We panicked at plaster coming off the wall when we first moved in and had a gypsum skim - which I now really regret and wish we had not done but it is too late to change now.
We just got a dehumidifier which is helping a lot.

View attachment 15587

So what were dealing with is an internal ground floor wall? Are there any external walls?

Whats type of floor have you got down there, suspended or solid?

I'm no gypsum expert but the plaster may well still be drying as its winter and you'd expect the moisture in the plaster to slowly emigrate down the wall with the base the last area to dry properly.

 

[anthony12uk]

So what were dealing with is an internal ground floor wall? Are there any external walls?

Whats type of floor have you got down there, suspended or solid?

I'm no gypsum expert but the plaster may well still be drying as its winter and you'd expect the moisture in the plaster to slowly emigrate down the wall with the base the last area to dry properly.

I am not sure on the floor but there is an airbrick out front which I assume means it is suspended? Yes, this is an internal ground floor wall. It had a sticky residue on this part of the wall from the wallpaper we removed, which I now think was because the wallpaper glue was wet due to the moisture, so it is a longer term issue

 

[aockenden]

I am not sure on the floor but there is an airbrick out front which I assume means it is suspended? Yes, this is an internal ground floor wall. It had a sticky residue on this part of the wall from the wallpaper we removed, which I now think was because the wallpaper glue was wet due to the moisture, so it is a longer term issue

Do yourself a big favor and get curious enough about your house to figure out with certainty whether you have suspended or timber floors. Along with understanding your wall construction, it’s one of the most important pieces of information you need to know when troubleshooting oldhouse problems

 

[Lacan07]

I am not sure on the floor but there is an airbrick out front which I assume means it is suspended? Yes, this is an internal ground floor wall. It had a sticky residue on this part of the wall from the wallpaper we removed, which I now think was because the wallpaper glue was wet due to the moisture, so it is a longer term issue

Go to the wall in question and jump up and down on the floor, if its a dead impact and feels like it could break your ankles its a solid concrete floor, if there's any amount of 'give' or vibration in the floor its a suspended floor. A solid floor could be the cause of your damp wall.

 

[anthony12uk]

Go to the wall in question and jump up and down on the floor, if its a dead impact and feels like it could break your ankles its a solid concrete floor, if there's any amount of 'give' or vibration in the floor its a suspended floor. A solid floor could be the cause of your damp wall.

Thank you for all your responses advice. After a lot of jumping I think it may be concrete flooring (but hard to tell). I have a home energy efficiency assessment booked for a couple of weeks time so hoping they can provide more advice regarding the flooring - in the meantime will just keep waiting to see if the plaster dries out any more.