Loft condensation and bathroom extractor fan

[Kamikz]

I'm aware the question of loft condensation gets asked on here every few minutes, and I've looked through the forums at the responses to these, so I won't repeat whats been asked a million times already (hopefully).

Anyway, moved in to my house in the summer, then recently noticed bad condensation in the roof, so not sure if this is the first time this problems occured or not. The insulation in the loft is pretty good, apart from the hatch, which is just a wooden hatch with no insulation on top, although it seals fairly tight. There is ventilation in the eaves all the way round the roof and from looking from the outside there are some ventilation tiles further up the roof. Now, I also have an extractor fan in the ensuite which goes to a flexi ducting in the loft and goes along a bit and through a tile and that all seems pretty well sealed, but there is loads of water in the duct, and I had noticed the extractor fan dripping recently.

I'm assuming the water shouldn't be in the extractor ducting, I didn't just want to pick it up and pour it all out through the extractor itself with it being electric, but not sure how to get rid of it. And is this likely to be the cause of the condensation in the loft, there doesn't seem to be any breakages in the ducting, so can't see how it could be? Or is the loft condensation likely to be caused by something else?

Thanks in advance for any help/advice on the situation

 

[JohnD]

you can prevent steam condensing inside the duct by wrapping it in insulation taped or tied in place. It is possible to get a duct condensation trap but I have never needed one. i would suggest the fibreglass that has a plastic sleeve round it - it's called "Pink anti-itch" or something like that. I am convinced that it is best to have the extractor come on whenever the bathroom light is switched on, not just when it occurs to the user. More frequent airflow (not always steamy) will help dry out the duct, as long as it is not cold.

the other condensation is probably unconnected

If you have any water tanks in the loft check that they are cold, not running over. and have tight fitted lids. Improve eaves ventilation at both sides so you get air movement

If you have holes in your ceilings e.g. for downlighters the warm moist air will rise through them

See what it is like on a non-frosty day.

Do you drape wet washing about the house?

 

[Kamikz]

Thanks, will get some insulation on the ducting.

The loft is pretty clear and nothing is blocking the eaves, so there's not much I can do there, there's no water tanks or anything up there, just the extractor ducting, and no down lighting either. After having another look I noticed there's only ventilation tiles on one side of the roof, but the whole loft is full of condensation. And no, no wet washing is draped around the house. This is what's annoying as after reading the posts about this on here my loft seems like it should tick all the boxes and not get condensation.

 

[JohnD]

then you just need more ventilation, low down, on both sides of the loft, to get an airflow. If you have gable walls you can hire a core drill that is surprisingly easy to use (dusty though) and you can drill from inside, provided you take precautions against falling bricks outside (and you will get some spalling). I would suggest two holes each end, low down. You will want plastic grilles on the outside, and a duct through the cavity. very much like fitting for an extractor fan.

or you could have air-bricks but this will need more work off a scaffold.

start by pulling back the insulation at the eaves as this is so easy. If you have soffit boards, drill more holes in them. Go up on a rainy day and look for any signs of roof leaks.