Ever growing patches on our living room walls

[BBV2021]

Hello, we have been in our house for a year now and these patches are getting worse on our living room walls. On the other side of these walls are our kitchen and utility room. We have a decorator booked for the end of November so we want to sort the issue before it gets decorated. When reading around the gist I’m getting is that it is probably condensation causing the problem, would you agree? We have our tumble dryer in the utility on the other side of the wall, although the previous owners didn’t have one and the patches were visible (although definitely not as bad). Thank you.

 

[Dekzion]

How is your tumble drier vented? externally hopefully.
The utility room could be warmer and wetter than the living room which means the wall behind the tumble drier is attracting the moisture as it will be colder than the air of the utility room which will attract moisture and it will soak into it permeating right through the wall to the colder room. is that why the rad is there? trying to dry out the wall? This can only happen of course if it's a solid wall not a stud wall.
I'd get a hydrometer gauge and see just how much moisture is in the air (above 55% is bordering on wet, I like it at no more than 50%) investing in a dehumidifier would be a smart move, and you'll find that once you get the humidity down the whole place will feel warmer too. They are definitely not expensive to run and repay by not needing heating on so high.

 

[BBV2021]

Hello, thanks so much for your reply. I’m afraid it went through to my junk box so I have only just seen it. It was a condenser dryer (since this thread it has given up and we have had to buy a new one - we have chosen to go for a heat pump dryer in the hope of it being better for causing less heat/condensation). This all makes a lot of sense and I think you’re right. Our decorator put some stain block on and so far it all looks fine. Although we haven’t yet got our tumble dryer in and going. I am planning to ventilate the utility room a lot more when it is in use and a dehumidifier sounds like a very sensible idea. Thank you for taking the time to reply.

 

[BBV2021]

How is your tumble drier vented? externally hopefully.
The utility room could be warmer and wetter than the living room which means the wall behind the tumble drier is attracting the moisture as it will be colder than the air of the utility room which will attract moisture and it will soak into it permeating right through the wall to the colder room. is that why the rad is there? trying to dry out the wall? This can only happen of course if it's a solid wall not a stud wall.
I'd get a hydrometer gauge and see just how much moisture is in the air (above 55% is bordering on wet, I like it at no more than 50%) investing in a dehumidifier would be a smart move, and you'll find that once you get the humidity down the whole place will feel warmer too. They are definitely not expensive to run and repay by not needing heating on so high.

How is your tumble drier vented? externally hopefully.
The utility room could be warmer and wetter than the living room which means the wall behind the tumble drier is attracting the moisture as it will be colder than the air of the utility room which will attract moisture and it will soak into it permeating right through the wall to the colder room. is that why the rad is there? trying to dry out the wall? This can only happen of course if it's a solid wall not a stud wall.
I'd get a hydrometer gauge and see just how much moisture is in the air (above 55% is bordering on wet, I like it at no more than 50%) investing in a dehumidifier would be a smart move, and you'll find that once you get the humidity down the whole place will feel warmer too. They are definitely not expensive to run and repay by not needing heating on so high.

Hi Dekzion,
I’m hoping to pick your brains as you obviously know what you’re talking about. I have been ventilating our house a lot more, trying to use the tumble dryer less and have borrowed a dehumidifier but the patches that used to be there before decorating the room are slowly reappearing. Which room would you be putting the dehumidifier in? The utility where the tumble dryer is or the living room where the problem is occurring? Do you have any other thoughts on what to do please?

 

[Paul Cumbria]

Hi BBV2021,
I might seem a bit obvious but have you checked that there are no leaking pipes anywhere above the problem wall? Water can migrate quite some distance from the area of the actual leak. Also, is the roof leaking? If the patches were present with no tumble dryer, then this is probably not the cause of (but may exacerbate) the problem. With a radiator situated below the damp patches there should not be a problem with condensation.
Kitchens are a major source of moisture in the air, you don't say whether or not the kitchen is ventilated, but if not, this would certainly help.
Also, stain block is a waste of time and money if the cause of the stain has not been eradicated.