Damp patch underneath window sill (pics inside)
- Thread starter martin645
- Start date
Sponsored Links
Oh.
Not being the sort to force my views on others i'll tread carefully.
Joe, you are right it is condensation....but....why does the condensation manifest it's self in a particular place when the weather turns very cold but still dry?
It is my opinion that condensation shows it's self on the first coldest surface, therefore, there must be a reason the surface in question is cold. The logical conclusion in some/most cases is a thermal bridge transfering cold from an external surface to the internal.....therefore, cold bridging..
However, i accept this is not the only way damp/mould can occur.
Sponsored Links
Thanks for all the replies, guys - seems like I have started a bit of a debate!
Anyway, an update: by Sunday evening (about 48 hours after I took the first photo) the wall was almost completely dry, even though it had been raining. Then we had another very cold night on Sunday night (quite a bit of snow in the garden in the morning) and it was damp again when I woke up. So I think the condensation theory is looking more and more likely. I have ordered a dehumidifier which I will try running for a few days and that will hopefully answer the question definitively.
Now, on to the underlying problem: by 'cold bridging', do you simply mean that there is inadequate insulation between the surface of the inner wall and the outside right? I.e. cold air is finding its way in? Presumably this is not ideal from a keeping-the-house-warm and an energy-bill point of view! So is the long-term fix to add some insulation, right?
joe-90, if I wanted to cut a hole and add some insulation, what is best way to go about it? cut a hole in the inside wall? outside wall? drill down through the window sill? Apologies if these are stupid questions; I really am a complete beginner at this stuff.
Anyway, an update: by Sunday evening (about 48 hours after I took the first photo) the wall was almost completely dry, even though it had been raining. Then we had another very cold night on Sunday night (quite a bit of snow in the garden in the morning) and it was damp again when I woke up. So I think the condensation theory is looking more and more likely. I have ordered a dehumidifier which I will try running for a few days and that will hopefully answer the question definitively.
Now, on to the underlying problem: by 'cold bridging', do you simply mean that there is inadequate insulation between the surface of the inner wall and the outside right? I.e. cold air is finding its way in? Presumably this is not ideal from a keeping-the-house-warm and an energy-bill point of view! So is the long-term fix to add some insulation, right?
joe-90, if I wanted to cut a hole and add some insulation, what is best way to go about it? cut a hole in the inside wall? outside wall? drill down through the window sill? Apologies if these are stupid questions; I really am a complete beginner at this stuff.
The cold is outside.
The moisture is inside.
The cold is bridged from outside to in as a result of inadequate insulation.
Result- condensation forming.
Insulate and ventilate.
Strip off plaster and fix some insulated plasterboard to the area below the window.
Joe's being....Joe.
The moisture is inside.
The cold is bridged from outside to in as a result of inadequate insulation.
Result- condensation forming.
Insulate and ventilate.
Strip off plaster and fix some insulated plasterboard to the area below the window.
Joe's being....Joe.
noseall,
Thanks for the excellent summary!
Thanks for the excellent summary!
Did we come to the conclusion there was or wasn't a cavity? If there's no cavity then insulating the interior wall will help, but may move the problem to the next coldest area.
If there is a cavity then insulating that would be sensible. Of course if there is a cavity and that part of the wall is physically bridged then removing the bridge would be a good idea.
Before deploying the big hammer a lot can be achieved by making a few lifestyle changes, are the dogs still sleeping in the room? Are you leaving the door open to allow air movement from the room?
Certainly a dehumidifer would help to remove moisture generally but i doubt you'd want one of them rattling away all night, maybe some sort of extractor possibly on a timer would help, i don't know if there's a silent running extractor which would be suitable for the purposes of a bedroom.
The answer is to manage the moisture level in the room against the cold outside as best and economically as possible.
If there is a cavity then insulating that would be sensible. Of course if there is a cavity and that part of the wall is physically bridged then removing the bridge would be a good idea.
Before deploying the big hammer a lot can be achieved by making a few lifestyle changes, are the dogs still sleeping in the room? Are you leaving the door open to allow air movement from the room?
Certainly a dehumidifer would help to remove moisture generally but i doubt you'd want one of them rattling away all night, maybe some sort of extractor possibly on a timer would help, i don't know if there's a silent running extractor which would be suitable for the purposes of a bedroom.
The answer is to manage the moisture level in the room against the cold outside as best and economically as possible.
Sorry to resurrect an old thread; just a quick note to say that moving the dogs out of the room and running a dehumidifier occasionally has solved the problem.
Many thanks for all the advice.
M
Many thanks for all the advice.
M
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
Sponsored Links
