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Could my roof felt be the cause of the condensation?
My roof is good but was built in 1935(approx) could the felt be the cause of the condensation? The whole house is rendered. The condensation is around wall of the windows, the corners of the room and most mornings the window sills are puddled. Would new felt under the tiles help? if so what material should be used? Other options that a roofer advised was ventilation in the soffits. I have also heard that roof vents might work. Any advise would be gratefully received.
It is unlikely to be the existing felt causing condensation in the rooms , you could probably improve things by increasing the insulation in your loft to 250mm thick , then place tile vents into the loft above the insulation level and look at the possibility of trickle vents in the top of the windows. You do not say whether you already have double glazing or secondary glazing but if not this would also help. You need to contact a few experienced roofers or builders off mybuilder to do a site inspection because it is difficult to advise you without seeing the problem first hand . They will quote you for the required work , but make sure you always get a detailed written quote. This time of year it is important to allow the moist air to escape the building by different methods of ventilation. otherwise it settles on cold surfaces [ glass etc ]
Answered 14th Dec 2012
One morning pop your head up into your loft and see if there is any condensation on the underside of the felt,If there is this is due to warm air rising from the bedrooms through the ceilings and condensating on the cold felt this is be caused by a lack of loft insulation, if you just put vents in it would make it worse, I would be very surprised if this is what is causing your problems in your bedroom though this is more likely to be condensation . Are the cavities insulated on your property ? If not this is probably not helping ,Have you got double glazing with trickle vents built in? Some times dry lining the affected areas with plaster board then skimming them helps buy creating a warmer surface to the wall thus stopping the warm humid air from condensating
Hope this is of some help
Answered 9th Jan 2013