Condensation in loft space

[electroman68]

Hi There,

I have a condensation problem in the loft and it is more problematic this year, presumably due to the very cold weather at the moment.

The condensation forms as beads of water on the underside of the roofing felt membrane.

One of the main problems I suspect is the drying of wet clothes in the house, but I am purchasing a tumble drier to hopefully address this problem.

However, I have noticed some other possible causes of the problem and wondered whether anyone could give any guidance on these.

1. The upstairs airing cupboard where the combi boiler is located doesn't appear to have a proper plasterboard ceiling, and instead 'appears' to have a thin hardboard panel nailed up. It also has gaps around the edges where it isn't quite the correct size. There are air vents in the airing cupboard door.

2. In addtion to the above point, the downstairs broom cupboard, which is directly below the airing cupboard, also doesn't have a proper ceiling. The door on this also has air vents.

I am wondering whether warm damp air from cooking/clothes drying is going through the vents and up seeping up into the loft via the gaps around the edges of the hardboard celing in the airing cupboard. Does this sound like a probable cause of the problem?

Also, I have looked at the eaves from outside the house and cannot see 'any' obvious vents fitted. Would it help the problem if I fitted some soffit vents? I would need to check whether there is any asbestos behind there before I drill though.

Finally, there appears to be cracks around the edges of the celings where they meet the walls in some of the upstairs rooms and I have purchased some flexible filler to seal these.

I recently had extra loft insulation put in as part of one of the governments energy saving grants. There are no holes/airbricks in the gable walls. I have one ridge vent.

I hope someone can advise on the above and I am happy to provide more details if necessary.

Thanks,
Robert.

 

[mointainwalker]

Does this sound like a probable cause of the problem

Yes, but all-in-all your ceiling/loft barrier sounds like Swiss-cheese.

Correct method of stopping moist air getting into loft is to put a vapour barrier ( plastic-sheeet) over the ceiling and joists and have the insulation on top. You should also ensure that the loft remains well-wentilated by not taking the insulation right out into the eaves where you would expect to find gaps/vents to allow air-circulation.

 

[electroman68]

I have checked the there is a gap of around 2 inches between the eaves and loft insulation. I cannot see any daylight at the eaves so am wondering whether there is actually any ventilation at all. Would it be beneficial to install some soffit vents? I was thinking of the 70mm diamter type that push in and twist to lock in position. If so is there a rule of thumb to use in terms of how many I would require per metre of space?

I have also ordered a tumble drier to help minimise the amount of warm damp air circulating around the house. I am using some flexible filler to fill any gaps around pipes and light fittings.

Thanks.

 

[electroman68]

I forgot to mention in my previous post but it is a semi detached property and I have checked with my neighbour and they don't have any condensation problems in the loft. They don't have a vapour barrier across their celing either.

They do, however, use a tumble drier and so don't have wet clothes drying around the house, which I suspect is a major cause of our problem. I have now ordered a tumble drier anyway.