Water droplets on roof lining

[simonelks]

I have a terrace house built in the early 1900's. Three months ago I had the roof replaced.

Last week I noticed on the inside of the rear bedroom wall next to the window was a damp patch which I have not had before. It is about 4 foot square and 3 foot from the ceiling.

Today I went into the loft and noticed the roof lining had several water droplets on it.

Are the two linked and how can it be resolved.

Many Thanks

 

[JohnD]

I expect your original roof was built without needing any ventilation as there were draughts between the slates. the felted roof is much tighter. Have a look at the eaves and see if there are gaps (you may need to pull the insulation back a couple of inches to unblock them.

If not, you will need air bricks or other vents. If you have gable end walls you can use a core drill at each end to get a good throughflow of air.

Otherwise you can ask your roofer to come back and fit some vent tiles on each side

If you have water tanks up there, check that they have tight-fitting plastic lids, and are cold, not warm. Look for any signs of plumbing leaks or roof leaks.

Also, make sure you are not generating excesssive moisture in the house, e.g. from wet washing or bathrooms without extractors.

A well-insulated roof will benefit from lots of ventilation (but lag the pipes and tanks)

Check that the loft hatch fits we to prevent warmth and moist air rising through

Check round any pipes or light fittings, especially from the bathroom, as steam can escape up through gaps.

 

[simonelks]

Thanks for the reply.

I have spoken to the occupiers and they have been propping the loft hatch open slightly to allow a lead from the TV ariel to go into one of the bedrooms. I take it this is not helping?

 

[JohnD]

it will allow warm moist air into the cold loft.

water vapour is lighter than air so it rises

here at least it has been frosty day and night so the water will condense and not dry out

//www.diynot.com/wiki/building:condensation_in_houses