Extractor fan in bathroom

[Richard Conway]

Hi people, we are wanting to put a fan in our bathroom but are having certain logistical issues! The problem being that there is only one outside wall and there are certain problems getting to it from the outside. The possibilities and potential downfalls are as follows:

1) Putting it over the window on the outside wall - this would be no problems from the inside, but the work required on the outside would be very tricky because there is a one story extension underneath which has a fairly steep sloping roof, the slope running perpundicular to the bathroom wall. I can't see any way of getting to the wall to make a hole/fit the outisde part of the fan. The roof is too low to stand on and there is no way of getting ladders up from the ground as the extension is in the way! Can anyone think of a way around this?

2) Put the fan on the ceiling and have it venting to outside through ducting to the (easily accessible) outside wall at the other side of the house. I don't think this is practical as the ducting would have to run about 2 metres through a cold loft and any steam would certainly condense before reaching the outside.

3) Put the fan on the ceiling and vent through the roof - wouldn't consider DIY-ing this so would have to get someone in to do it - any ideas how much this would potentially cost?

4) ...erm, I ran out at three - if anyone can come up with a workable alternative then please feel free to let me know!

Thanks in advance, Richard

[Owain]

My bathroom fan has about 6 metres (up through the flat above, and then up through the pitched roof). Condensation is not usually a problem provided you can go up a bit and thereafter having the duct sloping towards the outside. You can also get condensation traps for ducts.

For ductwork you need a centrifugal fan, don't expect the cheapy 4" axials in the sheds to push air through more than a foot or so. You can also get in-duct fans, which might make things quieter in the bathroom (or adjacent bedrooms).

Not that difficult. You can get 'roof terminals' for extractor fans, or stick a 4" pipe up through the slates, flashing in the same way as for a soil pipe etc, and then a 'mushroom' on the top of the pipe to stop the rain coming down.

Or would it just be easier to put a fan in the window rather than the wall?

Owain

[Richard Conway]

Would you need to seal the joins in the ducting somehow to make sure that water didn't leak at any point?

Sounds like cost is spiralling!

I think I like this idea best, but I'm not too good with heights so I don't envisage doing it myself!

I knew there was another option I had come up with but couldn't remember it! The window did seem like quite a good idea at first, as it has two sections, one thin long one at the top and another large opening section below. The top section should just about fit a 4" fan I think. The only problem when I looked was that it is a uPVC window sealed from the outside. I have no idea how easy it is to remove the panels from uPVC windows, but again I have the problem of accessing it from the outside to get the glass out/put it back in!

I suppose I could totally remove the openable bottom unit by opening it and removing the screws from the hinges and then lifting the whole thing back in through the window. This would enable me to go out backwards head first and sit on the windowsill facing inwards! I would worry that I would drop the bottom bit after I unscrew it though!

[Owain]

Yes, but the ducting should be sealed anyway so the moist air doesn't leak out. You need to arrange it so any condensate runs somewhere definate rather than puddling in the duct and going mouldy.

There may be another option - go down and through the floor void to an outside wall. Rectangular ducting will fit parallel to joists.

Owain

[Mike]

You mean you actually use it ? I thought these fans were just to meet the building regs and then the switch was turned off forever.

[Steve W]

Vent-Axia Quick Fix termination - 56 35 35B?

The only online supplier I've found is Deal Electrical

(about 2/3 down the page).

I've used a couple of these after drilling from the inside with a core drill. No access required from outside. There's nothing to stop backdraught but the fan I used (Vent-Axia Silhouette) had a simple shutter built in.

[Owain]

Of course I use it. I have an internal bathroom and without the fan it gets very steamy. It's a good quality fan, correctly sized for the job, so it is effective without being noisy, it's certainly quiet enough that I don't have to turn the radio up.

Owain