Attic felt sweating.

maveli

I went to the attic today an noticed little water drops on the felt on one side (the whole side). It doesn't look like a leak as the whole area is having water drops. Any idea what is the cause ? It looks like the felt is sweating

Thanks
maveli

Mikeyorks

It's condensation. Common in this cold weather and where ventilation of the roof area is inadequate.

Very cold on the roof side of the felt interacting with warmer air from inside the house = condensation. Needs additional ventilation in the attic area.

maveli

thanks. does this mean i need to install couple of extractor fans in the attic ?

ormus

no.
you need more/better ventilation, and or, better insulation to stop the heat rising from below.

andrew-b

...and you need to read the dozen or so other posts on this subject in the last week or two!
Seriously does noone use the search function any more?

Mikeyorks

maveli wrote: »

thanks. does this mean i need to install couple of extractor fans in the attic ?

No - as post #4 you either need to improve the insulation to stop the warm / moist air rising and meeting the cold of the felt. And / or you need to improve the ventilation. Via air bricks / air vents ... situated between the insulation and the felt