Condensation in Loft - Flue from Wood Burning Stove?

[drekkly]

I've read the Sticky on condensation but there was nothing that mentioned a flue from a wood burning stove. We had one put in last winter and noticed last week going up into the loft severe condensation on the black roof lining. The roof was new when the house was extended 4 years ago - the loft space is very small and we have 2 bathrooms where the extractor fan comes on automatically when you pull the light switch. We are guilty of drying clothes on radiators at times but not excessively. I will seal the loft hatch and check the loft insulation to see if it goes right into the corner. I can see no soffit ventilation grills on the front on the house where the soffit is very wide. On the rear of the house there appears to be a ventialltion point but not 100% sure.

So is there any way the flue could be contributing to it? I would say the only way I can think of is that it is purely sealed going up into the loft and this is allowing warm moist area to penerate. Otherwise the flue heating up would raise the temp of the air in the loft and should stop the condensation forming?

Any advice greatly received.

 

[majorevent]

are you 100% sure your bathroom extractor fan is venting directly to the outside? If your ducting or connections at either the fan or the extraction point is damaged or not "air tight" you could be pumping moist air into your loft. It would be normal to instal sofit ventilators but with out more info bit hard to tell.
A quick tip on how to test the duct work... light a scented incence stick or cone close to the fan and opperated the light, get up into the loft quick and if you can smell the incense you need to re seal the duct work.
as for the moisture from the stove/fire, the condition of the flue should have been checked by the installer at the time. this would have been done by using a smoke "bomb"..... the procedure is a little involved, not really a DIY job.

 

[mointainwalker]

Flue - single or double-skinned ?

KW output of stove ?

 

[drekkly]

Stove is 7kw output and the flue is double insulated from lounge ceiling up through. Been up this eve and still condensation - roof joists very damp where they touch the felt. Where the flue come up through seems to be well sealed. So thinking it's not the stove. The thing is I didn't notice it before we had the stove installed but then I only ever go up there at this time of the year to get the Xmas decs down and it han't been this cold at this time of the year before.

The loft is very small so big job to get round to the en suite and do the test on the extractor fans - will try and get round there at the weekend if still bad. I did notice the insulation going right up into the eaves but then if I have no ventilation grills in the soffit at that side of the house I guess it makes no difference

Coult try sealing the loft hatch as other have suggested but it doesn't seem too bad a seal??

Bottom line - is it something that is going to need resolving seeing as this is extreme weather and hopefully wont continue too long?

 

[mointainwalker]

Does you have a seal register-plate to flue on each floor level as that could otherwise suck up a lot of heated air ?