For the second winter running, the felting of one corner of the roof inside the loft is covered in condensation. This then runs together and drips onto the insulation and boarding I have up there. I have no idea what could be causing it but am considering getting a roofer to have a look. Is this the right approach or should I try a building surveyor first? The house is only just over ten years old and is detached. Any advice more than welcome.

Cheers

Andrew

Hi Andrew
I had a similar problem and found that it was being caused by insuficiant ventilation and cured it by..
1.pull all insulation away from the eaves
2.drill 70mm holes in the soffit @ 900mm centers and fit 70mm vents
3.remove single roof tiles near the ridge @ 2500mm centers and fit matching tile vents.

This provided through ventilation and stopped the condensation

Mog

I was just about to say the same sort of thing ;)

Huxley

Thanks for the advice guys, I had guessed it might be something like that - looks like a bit of work is required :-(

The previous answers are correct.

To avoid condensation within the roof space you need to cross ventilate(if it is a normal open plan storage attic), and this is is achieved through ventilation at the eaves on opposite sides of the roof space. Retro-fitting ventilation is best achieved by fitting the circular push in soffit vents and as stated earlier, ensuring that the loft insulation is not blocking air flow. In a new build ii would generally be achieved using over eaves grille ventilators and rafter trays.

If you have an attic room you must ventilate at both the eaves and the ridge as cross ventilation through the loft space is not possible.

This is all covered under current Building Regulations (applying only to new properties or extensions).

Dave

yep thats the trick . Whats happening is the moisture in the roof space is reaching its dew point and condensing out onto the colder surface. Bit of my old structure stuff from Uni.

I had a delightful time on my belly at the weekend discovering what was happening. I have grille ventilation all the way around the eaves so no need for extra vents. However, the fibreglass insulation was stuffed right down in the eaves so they were all totally blocked (must have been like this since new, I would guess?). I moved some of the insulation but then decided I needed to be a bit more careful about messing about with it so went off to the local DIY store to buy a mask, goggles and gloves (better safe than sorry, I reckon). I'll plan to go round the rest this weekend and then wait and see what happens.
Thanks for the advice, everyone.

Cheers

Andrew

Asking a roofer for advice will most likely result in him saying that you need roofing work done :(
Impartial advice is what's needed, and it looks like scoobynet has come to the rescue!

Fibreglass is great fun, innit? I fitted an extractor fan in the bathroom at the weekend, which vents up through the loft to the soffet via flexible ducting. Connecting the ducting to the vent in the soffet is, without doubt, the hardest nightmare job of the bathroom so far which is saying something...

I didn't use any special protective cloting other than long sleeves. I'd advise gloves and a mask with hindsight :D