Converted loft = Condensation?

skypie

Hi,

I have had an ongoing problem with my roof and loft. I have had about 5 roofers out all with different theories to my problem.

I am getting reasonably bad damp on 3 of my walls upstairs. These are all outer walls and all by windows. At first we thought this was because of rain coming into the house (we were led to believe this!!). This didnt make sense however seeing as last year during the awful wet period in the summer we had no problems. It was only in the winter it started and when we had the heating back on. The latest theory therefore is condensation.

When we moved into the house a previous owner had done a loft conversion (professionally? doubt it!). After looking all over the net there are a few things which don't make sense.

I have added this photo album to show what I mean
http://good-times.webshots.com/album/562627123WsvIET

Above the walls which have the damp is damp looking insulation. This insulation appears to go right to the end of the roof which I believe is incorrect?

There is also no other signs of ventilation in the attic except a velux window. I can see no place where the air can escape.

The felt near the end of the roof is slightly moist but not soaking wet.

What do I do to get rid of the damp. Is it because of a lack of ventilation and/or the insulation covering any gap which needs to be there?

Thanks for any help.

amd

From what it's possible to see in your photos there does appear to be a lack of ventilation at the eaves. Depends on the age of the house. Do your neighbours have any type of ventilators in their roofs or soffits (the flat part under the gutters)? It would appear you do need to have something installed, or at the very least pull back the insulation to let in any natural draughts that may occur - as was the way in the old (not necessarily better) days. Why this could result in damp walls below should be investigated further, but it could likely be the condensation/dampness moving downwards through solid walls - assuming it's not coming from the roof itself. Reducing warm moist air entering the loft space is critical too. Good bathroom/kitchen/bedroom ventilation is key.

skypie

Thanks for the reply.

The house was built in 1979 so it isnt very old.

The walls with the damp are also near windows which could well be the condensation from them. Its one corner of the ceiling with damp which is probably the damp insulation above it. I was thinking of buying those small window ledge dehumidifiers which are supposed to help reduce condensation on windows.

Im not sure what the neighbours have installed in their houses.

nalyo

i would agree with AMD .....immediate action to fold back or even remove 30cm from the edges of the roof. give the roof some air.

emweaver

did you remove any from the edge?im asking as we have the same problem and our insulation goes right to the edge of the ceiling, if it worked for you was going to try it out

baldelectrician

Things I have noticed (please note I am a mere electrician and not a building surveyor)

There are no vent tiles (I have 6 on my old roof - 3 front & 3 back). My roof was redone in 1996

There seems to be a lack of ventilation on the soffits- there are usually trickle vents or round vents every so often

The loft insulation seems to go right to the edge- this bridges the ventilation gap between the inner and outer leaf of the dwelling.

There is no sarking board. Almost all lofts I enter have wooden board between the joists on the face of the roof. (this seems to be a Scottish thing)

I think you should remove and replace the damp / mouldy insulation and ensure better air movement. This may solve or greatly reduce the problem

Get a dehumidifier as others have suggested

Hope this helps

27col

It appears from the photos that the insulation goes right up to the wall and thus prevents any ventilation draught from flowing, so pulling it back a bit and inserting vents into the soffits if needed, should help a lot. I have been reading the recent posts about roof condensation and thought that I would inspect my loft. There do not appear to be any traces of condensation, but I did notice quite an airflow in the loft, so presumably I do not require any extra vents.
I have never seen any condensation in any of my rooms and never felt the need for de-humidifers. I think it is all down to the level of heating and insulation. I tried to get a poll going about insulation levels but no one was interested.