Just been up for the Crimbo decs and noticed a lot of condensation on the inside of the felt!!

Had the cavity walls and the loft insulated this year so think that is the cause but any ideas how to sort this ?

Guess there are a few roofers etc on here so would be grateful for any tips.

You need to have air circulating. Air bricks in the eaves or such like should do it. Has the new insulation blocked off the air ways?

Have you got any ventilation for the roof space?.If not, that may help.

http://www.tipking.co.uk/loft_ventilation.shtml

Richie London wrote on 12. Dec 2009 at 14:21:

http://www.tipking.co.uk/loft_ventilation.shtml

soffits will always be the best place in my opinion. ive put them in 3 houses and added to loft conversions in the past.

What they said  ::)  most made mistake when insulating a loft is covering the vents --- need a good airflow up there

Is it really condensation?  Could it be water due to a missing / displaced tile or two?? :-/ :-/

omegod wrote on 12. Dec 2009 at 13:51:

Just been up for the Crimbo decs and noticed a lot of condensation on the inside of the felt!! Had the cavity walls and the loft insulated this year so think that is the cause but any ideas how to sort this ? Guess there are a few roofers etc on here so would be grateful for any tips.

Sources of moisture up there are uncovered water tanks (especially hot water expansion) and hot air rising from the floor below through gaps, in addition to leaks.

Reduce sources and add/unblock ventilation.

I had the same problem & had to fit double size airbricks in either gable end to cure it.

Has someone had the lead off your roof Jon ;D