Noisy extractor fan in loft bedroom

billybobster123

We’re in the middle of a loft conversion and have noticed that the extractor fan from the bathroom situated below is very noisy - far noisier than in the bathroom downstairs. The noise is coming from the wall which the ducting runs behind before it is vented outside. If you touch the wall you can feel the vibration of the ducting. 

This is a photo of the ducting wrapped around the studs before it was boarded and plastered. 

Can anybody advise whether this has been installed incorrectly from this photo and whether it is causing this issue? Or are there any other suggestions?

Any advice would be much appreciated. As mentioned above, the room has now been plastered so it would be a messy fix at this point.

Thank you!

molerat

I wouldn't think the ducting is vibrating, it is too soft for that. More likely it is the fan itself below vibrating through the ceiling into the floor and studs.  Where is the fan actually situated ?

billybobster123

That sounds feasible. It’s in the ceiling of bathroom on the first floor which is directly below.

Any thoughts on how we can stop these vibrations?

Thanks.

teaselMay

I'd try damping the fan, see if you can see how it's mounted, rubber or similar between the unit and the surface it's mounted on might help.

Make sure it's clean too, if it's not it might be vibrating more because of asymmetrical weight

Lorian

Did insulation get put between the duct and the outside wall? If not you may have condensation running back down the pipe into the fan.

FreeBear

Should have used smooth bore rigid ducting, not that flexible stuff. Smooth rigid ducting will provide less resistance to air flow and reduce the amount of noise being heard. But if you have a duff extractor with dodgy bearings or an out of balance blade, the type of ducting won't make much difference.

ThisIsWeird

Make, model, and age of existing fan?
You can buy uber-quiet ones these days, so that could be the simplest solution, but shame about the ducting used, and lack of insulation around it.
Some fans are fully automatic, responding to conditions, and run pretty much constantly at a low background (and completely inaudible) level to provide a constant freshening ventilation - might be a good idea to keep that large vertical duct run dry, or good chance you can anticipate condie trickling back down.
Where is the fan located in relation to that duct? Any horizontal section too?

Grenage

Rigid ducting reduces air noise but can increase vibration noise.  It seems more likely to be the fan mounting that's the issue.