Can I seal the boxing in around my soil vent pipe to minimise loft condensation?

[BathDIY]

My soil vent pipe goes up through the kitchen past the landing and correctly vents out of the roof via the loft.

I do have some small condensation problems in this part of the loft area despite fitting roof tile vents. I am speculating that the boxing-in of my soil vent pipe is acting a bit like a chimney and venting warm air into the loft space.

Can I seal the boxing in around my soil vent pipe in the loft and if so what's the best way to do so?

Also, can I insulate the pipe in the loft space and what should I use?

 

[cross thread]

Easy way is fill round pipe with loft insulation

 

[phatboy]

I'd suggest it is venting warm, damp air. Best thing to do would be ensure it is sealed in the rooms below, I'm guessing bathroom as the culprit? Wouldn't be surprised if there was a not very neat hole for the toilet waste, and warm wet air was getting through there.

If you just seal the top, the problem will just move further down. Once it's nicely sealed, insulate the top so cold air doesn't blow down.

 

[BathDIY]

Thanks, @phatboy will take a look, it also passes through the kitchen, should I think about insulating here in some way, it's just plasterboard at present?

If so can you point me in the right direction?

 

[phatboy]

Well it's inside the house, which is insulated in the cavity probably... or at least the boxing is no colder than the rest of the house. SO I don't think there is any need to insulate it.