Fixing a draughty bathroom extractor fan vent

[HaroldFinch]

Hi all,

I've recently been on a mission to fix all draughts in my house, and I noticed that a lot of cold air comes through the downstairs toilet extractor fan vent, especially on a windy day. The toilet is under the stairs, and the vent itself goes into a pipe the other side of the wall which seems to just go underneath the house. Is there any way to resolve this? Do I even need the extractor fan, given that it just a small bathroom with a toilet and a sink? As you can see from the photos, I've looked outside to see if I can figure out where the cold air might be coming in, but I don't know how to locate the source given that the pipe goes under the floor!

Any help would be much appreciated!

Thanks.

 

[stem]

If there is no external window in the WC that can be opened, then the fan is a requirement of the building regulations.

I fitted an outlet with a flap on that was designed for a tumble dryer. The air from the fan pushes the flap up when it's running, and it falls down by gravity when the fan isn't running. It does rattle a bit when it's very windy because air can still exit from the house via the fan if it is coming in elsewhere. But there's certainly no draught anymore, the harder the wind blows on it the tighter it shuts. It may even be what is already fitted to the outlet next to it. Although I can't see if it has a flap fitted.

Looking at your photo though, you would need to clear some space below the outlet to allow the air to escape freely.

 

[HaroldFinch]

If there is no external window in the WC that can be opened, then the fan is a requirement of the building regulations.

I fitted an outlet with a flap on that was designed for a tumble dryer. The air from the fan pushes the flap up when it's running, and it falls down by gravity when the fan isn't running. It does rattle a bit when it's very windy because air can still exit from the house via the fan if it is coming in elsewhere. But there's certainly no draught anymore, the harder the wind blows on it the tighter it shuts. It may even be what is already fitted to the outlet next to it. Although I can't see if it has a flap fitted.

View attachment 291188

Looking at your photo though, you would need to clear some space below the outlet to allow the air to escape freely.

Thanks so much for your reply, and apologies for my slow response. I'll take another look at the outlet tomorrow and take a closer photo. From memory I don't believe a flap is fitted though. Would I need to replace the whole thing? If so, do you have any links to an example of what I'd have to install instead please? Not sure how much space I could clear underneath but I'll have a look.

Is there any way I can confirm that those vents are definitely related to the extractor fan? I'm guessing they must be because there aren't any others!

Cheers.

 

[stem]

I can't remember exactly where I got mine from. It was over 20 years ago and I think it was just a local DIY shed close to where I used to work.

If you search online for something like Tumble Dryer Vent with Flap you'll find a few.

If you wanted to check the vents, I would either follow them physically to see where they go, or with the help of a friend to spray a small quantity of air-freshner into the fan whilst it's running see if you can smell it coming from the vent.

 

[HaroldFinch]

I can't remember exactly where I got mine from. It was over 20 years ago and I think it was just a local DIY shed close to where I used to work.

If you search online for something like Tumble Dryer Vent with Flap you'll find a few.

If you wanted to check the vents, I would either follow them physically to see where they go, or with the help of a friend to spray a small quantity of air-freshner into the fan whilst it's running see if you can smell it coming from the vent.

Cool, thanks - I'll do a google search now.

I took the front of that vent off and there's a big hole so I wouldn't be surprised if this is the cause of the draught - see the image below.

I can't follow the pipe as it goes under the floorboards, but your idea about spraying an air freshener is superb! I'll have a go at that and see what happens. Thanks so much for your advice.