Dripping bathroom extractor fan

[Minxy]

We have a fully enclosed bathroom with no window, it had a ceiling extractor fan for years that needed replacing so we had someone do that along with a few other jobs over the summer. Since the weather has got cold we have had water dripping into the bathroom through the extractor fan. I assume this to be condensation but I’ve lived in the house for 13 years and never had this issue before.

The pipe work in the loft is a solid pipe about 6 inches across and about 8 feet long and it’s vertical from the bathroom up to the roof vent. We’ve wrapped this in pipe insulation but it’s not solved the problem. We’ve tried leaving the light/fan on for a period after every shower but it’s still dripping now.

Would anyone have any suggestions on how we can fix this? I’m not even sure who to call, a heating engineer maybe or plumber?

It’s driving me mad so any suggestions would be gratefully received.
Thank you.

 

[robj20]

Fit a drain close to the internal vent.

 

[K.C. Leblanc]

Get the installer back to fit a condensation trap.

 

[Mysterae_]

If the design has been problem free for 13 years then maybe the new fan doesn't have the same flow as the previous or the installer has disturbed the roof vent and your getting rainwater in.

 

[Minxy]

If the design has been problem free for 13 years then maybe the new fan doesn't have the same flow as the previous or the installer has disturbed the roof vent and your getting rainwater in.

The guy never ventured into the loft so I wouldn’t have thought he could disturb the vent itself? I wondered about a more powerful fan but when I queried this he seemed to think it would make the issue worse because it’s pulling more steam out of the room so more vapour to then condense.

 

[Mysterae_]

I'd have thought a more powerful fan would have been better - get the moist air out the house before it has a chance to condense. The warm moist air is attracted to cold, even air not associated with the shower, from around the house, breathing, gas appliances etc.

 

[Sin_Chase]

While I appreciate the venting through loft has remained unchanged and this issue is new the ducting shouldn't run vertically to the roof vent like I imagine it is.

At the very least there should be a deviation in the run or trap to protect against direct ingress of rainwater and/or condensation dripping down.

 

[Minxy]

While I appreciate the venting through loft has remained unchanged and this issue is new the ducting shouldn't run vertically to the roof vent like I imagine it is.

At the very least there should be a deviation in the run or trap to protect against direct ingress of rainwater and/or condensation dripping down.

You’d think so wouldn’t you but no it’s pretty much straight up to the roof. We’ve got a water trap being fitted this week. I’m amazed we’ve not had issues with it before now.

 

[2004typer]

While I appreciate the venting through loft has remained unchanged and this issue is new the ducting shouldn't run vertically to the roof vent like I imagine it is.

At the very least there should be a deviation in the run or trap to protect against direct ingress of rainwater and/or condensation dripping down.

Yep - needs a condensation trap on a vertical pipe (noted OP now getting one fitted). Note that the trap will need an overflow pipe to discharge any build up to a drain point. If you are getting a lot of dripping might be worth also checking the roof extract point to make sure this isn't damaged as well so you've not the double issue of condensation and external water - the tile vent or ridge vent it connects to shouldn't allow any rainwater to penetrate.

 

[pp111]

The damper is probably stuck. In the vent in the roof there is a flap that prevents air blowing back down the pipe or there is one in the fan itself. If the damper is stuck with a vertical pipe then there is a constant flow of cold air downwards and a flow of warm water-laden house air upwards. The end result is a lot of condensation on the inside of the pipe even when it is not in use. I guess since it's a recent problem it's only recently it's got stuck.

 

[Minxy]

Yep - needs a condensation trap on a vertical pipe (noted OP now getting one fitted). Note that the trap will need an overflow pipe to discharge any build up to a drain point. If you are getting a lot of dripping might be worth also checking the roof extract point to make sure this isn't damaged as well so you've not the double issue of condensation and external water - the tile vent or ridge vent it connects to shouldn't allow any rainwater to penetrate.

I gather the trap will be plumbed into an existing overflow that we have for the water tank. We are also having a more powerful fan put in.

It’s been absolutely tiddling down with rain here today and we’ve had very little come back through the fan so I’m hoping it’s not an issue with the vent.

Thanks all for your input. Fingers crossed this new trap fixes the issue.

 

[2004typer]

I gather the trap will be plumbed into an existing overflow that we have for the water tank. We are also having a more powerful fan put in.

It’s been absolutely tiddling down with rain here today and we’ve had very little come back through the fan so I’m hoping it’s not an issue with the vent.

Thanks all for your input. Fingers crossed this new trap fixes the issue.

Yeah should be ok, end of the day it'll go to a pipe sticking out of the fascia so same as.

The only issue I could see perhaps is if the overflow pipe is blocked (very very unlikely), you'd get the water tank overflow backfilling into the condensate trap and back down your extractor fan ducting (that's if the tank fill float valve ever failed).

 

[Mysterae_]

Thanks all for your input. Fingers crossed this new trap fixes the issue.

Good luck and I hope you find a resolution.

 

[Minxy]

Thanks Mysterae

Ok, so the vertical pipe was removed and the hole up the the roof was covered up so nothing comes down it because the birds seem to enjoy stuffing moss down it.

The moisture trap has been put on just above the ceiling fan with a flexible pipe on top, this has been attached to an outlet on the existing soil pipe to allow the air to escape up the same way as the toilet smells do. The moisture trap itself has also been plumbed into the soil pipe with a length of pipe to allow any water to run down it and escape into the soil pipe.

I gather this can’t do any harm since it’s only a tiny amount of water anyway and it will just go down to the sewer along with any toilet waste.

This was Wednesday. We’ve been in the loft this morning just to make sure there weren’t any leaks after we had both showered and everything is dry and there is no drips coming into the bathroom now. Does all this sound acceptable? I’ve just had to trust the bathroom man.

Thanks

 

[norm]

Did the fitter put a waste trap before connecting to the soil pipe? Even with one to be honest if it dries up come the summer time you could get nasty smells coming back in through the extractor fan.

They should have just routed the condensate pipe to drip out the soffit.

Edit: having reread your post venting an extractor fan through a soil pipe seems majorly cowboyish, what's stopping backflow of gases into the bathroom when the fans not running??

 

[koolpc]

If they have connected to the soil pipe to vent steam from the extractor fan then this is absolutely wrong.

 

[Mysterae_]

As norm and koolpc have said, venting to the soil stack is a bit lazy and wrong for a few reasons all related to the stench gases of the soil stack. The stinky air is likely to make it's way through to the bathroom as norm says, when the fan isn't running. Also when it's particularly windy outside or blowing from a different direction the air may go down the soil stack taking the gases with it. You don't normally smell the stack during these times because the u-bends in the toilet acts like a one-way valve. You're new fan wont* and the gases may get in to the house on these occasions. When the fan is running what's stopping an equal amount of airflow going down the soil pipe affecting toilet flushing (it would have to be a powerful fan to do that though!).

It depends on the positive or negative air pressure of your house which varies throughout the year (more windows open). Anyway, it's wrong and I'm pretty sure against building regulations.

*Perhaps the fitter put a one-way flap/valve between the fan and the soil pipe which will limit the stink coming through.

 

[Minxy]

I don’t believe there is a one way valve between the fan and the soil pipe no. We do have the old pipe still so can replace this if needs be but obviously there is now a hole in the soil pipe if we remove the new escape pipe, the upper one has a cap that can go back on.

I’m guessing I’m going to need a new section of soil pipe and obviously the fan escape rerouting.

Question is, how do I now fix this? I don’t know who to call? The last thing I want is for anything to be against building regs. Thanks.

 

[Minxy]

When the fan is running what's stopping an equal amount of airflow going down the soil pipe affecting toilet flushing (it would have to be a powerful fan to do that though!).

Am I going to end up with a house full of nasties? Does this need fixing ASAP? I’m worrying now I’m going to come home to a bathroom full of brown smelly stuff.

It isn’t a very powerful fan by the way. The bathroom man eventually decided we didn’t need to change that.

 

[Mysterae_]

Some fans have an internal flap that only opens when the fan is running, mainly used to stop draughts.

Regarding building regs, the house I bought last year had the bathroom vent just extracting the moist air to the loft, which they then covered with insulation then boarded over! It wasn't picked up on the survey but I suppose it wasn't the full blown inspection, but anyway, way against building regs and potentially quite damaging. Your installation I doubt is doing any damage apart from your health if the smells start to become a thing. Have you noticed any smells?

How do you fix it? Ideally get the fitter back to do the job properly. The hole in the soil pipe will be easy to fix with the appropriate tape or an inspection cover as there's no pressure involved. Is your house particularly awkward that the fitter didn't fit a vent to the soffit or drill a hole through the wall for the vent? Either of these options are best.

Here's what I did quite recently - the extractor vent hole in the bathroom was quite a bit a way from the wall so I ran (somewhat ironically, sorry!) some 110m soil pipe to the outside with a flap vent on the outside wall.