I have condensation in my loft since having new windows and cavity wall insulation fitted in the summer. Having read some of these forums it looks like I need to fit soffit vents. Doesn't look too difficult so I plan to do it myself & fit the round type. I have noticed other houses in my street only have a few fitted, but I read somewhere they should be spaced every 200mm. Could anyone advise me how many I should fit, and how do I avoid drilling into something solid if I can't see whats under the soffit?! House is approx. 10m x 7m.
Soffit Vents
- Thread starter gunplumber
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If they are the round disc vents, every metre.
You will need some vents at high level as well, about a metre from ridge, tile vents are probably the easiest.
You will need some vents at high level as well, about a metre from ridge, tile vents are probably the easiest.
you might see the nail heads into the rafters on the fascia
Thanks for your replies. I'm not keen on climbing all over the roof to be honest. Would soffit vents help to alleviate the problem or should I look towards getting a roofer in if ridge or tile vents are needed? Was trying to avoid the cost!
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To be honest, get a roofer in you need vents at high level as well as soffit vents to get a decent air circulation.
I have the same issue as you and added just sofit vents the round ones, didn't fix the issue..I am now going for a few slate vents 2 on each side of house, this will be done after boxing day. The issue seemed to occur post cavity wall, the house is nice and warm not but no doubt changed the ventilation characteristics of the house so it's a case of keep trying things keep them crossed for the rof vents....I'm sure you will need both
We actually did the proper airspace calculation and it meant having a soffit vent every 18 inches
Everything I read seems to suggest you need air flow from soffits up to vents higher up on pitch of roof or ridge line. My attic space is cold but apparently not enough circulation of air up and out...will let you know how it goes. Houses are a pain in the ass but need to live somewhere
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I've got a similar problem to this and have done a lot of research around the subject and there's another angle that I thought I would point out.
Condensation is caused by moisture crossing a thermal barrier. In a house it's normally warm, moisture laden air hitting a cold surface and in the case of a loft it's moist air entering the roof space from below either directly from rooms or through a drafty loft hatch.
As insulation is improved the loft space should get much colder and cold air holds much less moisture than warm so the problem gets worse.
My point is; the other angle is to look at the relative humidity in your loft and your house in general and see if you can get it down. Make sure the hatch fits well (use draft excluder) make sure bathrooms have extractor fans, make sure light fittings are tight up to the ceiling or sealed, use fittings designed for a bathroom in the bathroom. Buy a digital hygrometer (they're not expensive) to check the humidity around the house and in the loft.
I'm not suggesting this is a magic cure; it's not. In all likelihood you'll still need soffit and maybe roof vents, but in my case understanding humidity and how it effects my house and loft has helped get the problem under control buying a bit of time to get the ventilation problem sorted properly and a less humid house if healthier.
Condensation is caused by moisture crossing a thermal barrier. In a house it's normally warm, moisture laden air hitting a cold surface and in the case of a loft it's moist air entering the roof space from below either directly from rooms or through a drafty loft hatch.
As insulation is improved the loft space should get much colder and cold air holds much less moisture than warm so the problem gets worse.
My point is; the other angle is to look at the relative humidity in your loft and your house in general and see if you can get it down. Make sure the hatch fits well (use draft excluder) make sure bathrooms have extractor fans, make sure light fittings are tight up to the ceiling or sealed, use fittings designed for a bathroom in the bathroom. Buy a digital hygrometer (they're not expensive) to check the humidity around the house and in the loft.
I'm not suggesting this is a magic cure; it's not. In all likelihood you'll still need soffit and maybe roof vents, but in my case understanding humidity and how it effects my house and loft has helped get the problem under control buying a bit of time to get the ventilation problem sorted properly and a less humid house if healthier.
There is no point fitting soffit vents if the air can not get past the insulation.
You also need to ensure that the insulation is not stifling the flow of air.
This is normally achieved by using eaves ventilators, a kind of corrugated plastic tray that allows air past.
You also need to ensure that the insulation is not stifling the flow of air.
This is normally achieved by using eaves ventilators, a kind of corrugated plastic tray that allows air past.
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