Condensation on walls

[ajp1981]

hi we live in an old cottage with thick walls
We recently fitted one of those fans that push air around the house
In the winter when it’s colder we are getting damp patches on the walls ( it’s not from rain ) . The front of the house has been re rendered , we just got a new roof , also it doesn’t specifically happen when raining .
We have the heating thermo come on a couple of hours before we wake
I suspect the condensation is down to the changing temperature of the wall
What is the best way to stop this ? Does it need to be warmer sooner inside ? Apologies for my naiveity

 

[motorbiking]

If the air is warm and walls cold, you will get condensation. Your choices are:
- insulate the inside of the walls with for example celotex backed plasterboard - this may not be practical depending on the age of your house. (you might not want modern plasterbaorded walls
- keep the heating on longer so that the walls absorb more heat and act a bit like a storage heater.

picture of the inside would help.

 

[ajp1981]

If the air is warm and walls cold, you will get condensation. Your choices are:
- insulate the inside of the walls with for example celotex backed plasterboard - this may not be practical depending on the age of your house. (you might not want modern plasterbaorded walls
- keep the heating on longer so that the walls absorb more heat and act a bit like a storage heater.

picture of the inside would help.

Thanks , yes the former isn’t really practical . I think we will have to keep the room warmer , however when it gets warm it’s very warm
No picture as yet as on the move

 

[JohnD]

There is also the matter of reducing the amount of water in the house. Wet air will naturally cause more condensation.

An old house may have a damp stone floor, which takes money and effort to proof, but are there easier things you can do? Do you have a powerful extractor fan in the bathroom? Do you ventilate bedrooms each morning? Do you drape wet washing over radiators? Is there any sign of leaking gutters or pipes?

 

[durhamplumber]

Ventilation!!..

 

[JP_]

Ventilation isn't the only answer, as otherwise, there would be no dew on spiderwebs outside ....

Trickle vents might reduce the problem though.

 

[durhamplumber]

Ventilation isn't the only answer, as otherwise, there would be no dew on spiderwebs outside ....

Trickle vents might reduce the problem though.

It is not permanent though,,because of ventilation!

 

[ajp1981]

It’s only in the bedroom based on what you have said it’s condensation , we don’t have issues in the bathroom it’s well vented, we don’t have an extractor but we do have one of those units in the loft designed to push air around . I’m starting to think it is things getting cold late at night

 

[StephenStephen]

Is the re-render lime or cement based?

 

[Ihavenojob]

It’s only in the bedroom based on what you have said it’s condensation , we don’t have issues in the bathroom it’s well vented, we don’t have an extractor but we do have one of those units in the loft designed to push air around .

Is there a leak on the ducting ?, assuming it draws air from the rooms.

 

[JP_]

It is not permanent though,,because of ventilation!

It's not permanent because the air and web get warmer when the sun rises, and the water droplets evaporate. Warming the room will increase the amount of moisture the room can hold. Keep it warm all the time, and no condensation (but massive energy bills).

External insulation is another option, if internal cannot be done. Ultimately, some insulation is needed to put an end to the problem.

 

[ajp1981]

Is the re-render lime or cement based?

Cement I think

 

[ajp1981]

Is there a leak on the ducting ?, assuming it draws air from the rooms.

Couldn’t tell you hard to get to , didn’t fit it . Can barely change a plug

 

[durhamplumber]

It's not permanent because the air and web get warmer when the sun rises, and the water droplets evaporate. Warming the room will increase the amount of moisture the room can hold. Keep it warm all the time, and no condensation (but massive energy bills).

External insulation is another option, if internal cannot be done. Ultimately, some insulation is needed to put an end to the problem.

More ventilation always helps.Stick as many rads in a room as you like,will still get condensation without ventilation

 

[foxhole]

More heat allows more moisture to be held in the air, ventilation is the only answer, always has been.