DIY Doctor

fibreglass condensation

Postby hamco63 » Mon Dec 12, 2011 2:38 pm

We had a complete new fibre glass roof installed 2 years ago on our dormer bungalow,previously it was felt, but we were getting some leaks. However we are getting drops of water now coming through the platerboard on our bedroom ceiling and also in light fitting in the upstairs bathroom and are quite alarmed in case there's serious damage being done. The installer came back to look but says there was no leak and basically that it wasn't his problem that he'd left the necessary gaps. We are in the horrible position of having paid a lot of money to have our dormer and conservatory roofs done( no problems seen yet in conservatory) and instead of being better off,we're considerably worse off.We've had a couple of people look at it who say that the roof isn't leaking and proposing different solutions such as air vents which isn't possible, to what they say is a condensation problem. We first noticed it in February in our bedroom, this year but it went away. However we have noticed drops of water on our bedroom carpet recently and slightly more in our bathroom next door. Can anyone suggest what is likely to be the issue and is it serious and how we go about getting a remedy ?
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Postby welsh brickie » Mon Dec 12, 2011 9:00 pm

if there is no sign at all of it being the roof leaking,then it could be condensation.The only way to stop that is to insulate the area. Hire a borescope from your local hire shop.Drill a small hole in the ceiling and any condensation should show on the camera.
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Postby xavi99 » Fri Dec 16, 2011 8:19 pm

It sounds like condensation. This is where warm air is percolating into the roof void from below. When the air gets cooler it cannot carry so much moisture and so the excess is deposited on cold surfaces as condensation.

The remedy is to provide a cross flow of ventilation usually via ventilation holes drilled through the soffit board.

The alternative is to prevent warm moisture laiden air getting to the roof void. Try to ensure that any moisture from cooking, bathing is extracted to outside as soon as possible and not allowed to move through the house. So when you have a bath, keep the door closed and then when you leave the bathroom, open the windows to get the moisture out.

It's not an easy fix but keep trying because little things can make a difference.

Good luck, hth,

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