Extractor Fan Noise - Vibration

[nellymcl]

Hi all
i was looking for some advice in cutting down the 'humming' noise from a centrifugal fan located in a downstairs WC. This room has a plasterboard ceiling with noting in the cavity between the ceiling and the upstairs floorboards.
I feel the addition of insulation (glasswool) above on the ceiling may reduce the noise, as well as running a bead of silicon around the underside of the fan.
Are there any other ideas of how I may be able to reduce the noise / vibration. e.g. rubber matting above the ceiling???
Thanks in advance
P.s I have 3 low voltage halogen downlighters (12V 20W) in the ceiling also which require airspace for overheating.

 

[timbalcombe]

I've been battling with this for ages.
I replaced my old one with a 15 quid one from wicks.
The reason for this was the other one had spring clips, where this one screws into the plaster board directly.
It still vibrates as the centrifugal motion is not completely uniform.

Anyway my point being is that a lot of twiddling, tightening, loosening screws and creating an opening for the wires is the only thing that has worked for me.

 

[nellymcl]

Thanks Timbalcombe
I have 'aquired' a foam mouse mat from work which I intend to mount the fan on to. I'll let you know how I get on.

 

[timbalcombe]

Cheers, Good luck.
Out of interest what fan do you have?

I have been looking at getting a more expensive model.

 

[nellymcl]

Its a screwfix centrifugal timer fan - £29.99

 

[timbalcombe]

Let us know how you get on please.

Cheers mate

 

[nellymcl]

Mouse mat made no difference
Back to the drawing board. I will put some insulation in at the weekend

 

[peteuk]

Hi,

I have the same problem too - from 2 fans. I in an internal bathroom and 1 in an ensuite (no windows).
Both fans are screwed onto roof joists. (I have screwed through highish density foam (shoe liner things)).
You could also try foam even though it hasn't worked for me to try and dampen the vibration. In my case does anyone know if it could be vibration in the joists - it doesn't sound too bad in the bathrooms? If so any ideas how to fix it?

 

[nellymcl]

I have now installed a Silavent Curzon 7003B Timer fan. Its a bit better but I think I am stil going to have to insulate the ceiling.

 

[timbalcombe]

You need to get it out of the joists.
It is the vibration rattling the joist which you can hear else where in the house.
It does my head in.
My fan has to be fixed at an angle, so the two sides that fit into the joist are not screwed up to butt up to the ceiling.
This has been the only way I can stop the vibration.

The best solution and one I don't really look forward to is to move the opening so its between the joists.
I'm not looking forward to that as some of the opening will need to be filled in obviously. I might be able to get an offcut of plaster board from B&Q or something?? As I don't want to buy a whole sheet just for a 30x20 piece.

 

[pitbull]

use clay plant pot's over your downlighters before insulating the ceiling

 

[peteuk]

Thanks for the advice about the joists. Please forgive the next stupid question but I'd like to be clear:
Do you suggest I screw the fans directly to the plasterboard above the ceiling?
If so am I in danger of damaging the underside of the plasterboard in the bathrooms? (I will need much smaller screws than those provided with the fan)
What about inducing vibration into the plaster board and to the newly installed downlights?
Should I retain some foam to dampen any remaining vibration?
By the way it was my builder who installed the bathrooms who attached the fans (Both Silavent) to the joists.

 

[nellymcl]

PeteUK
I have installed my fan directly to the plaster board using drywall fixings. The platerboard appears to be undameged, apart from the screwholes obviously

 

[peteuk]

Thanks nellymcl,
I think we have different installations. My fans are attached to ducting that leads to the bathroom ceilings. Therefore if I move the fans from the joists they will attach directly to the plasterboard of the ceiling.
I am worried that the vibration, then in the plasterboard, would cause movement in it so that the result could be what would look like cracking of the ceiling where the plasterboard butts up to another board. There is also the possible effect on the installed downlights.

Can anyone think of another method?
Thanks
Pete

 

[empip]

Can you make up a fan unit mounting plinth which 'hangs' from rafters...
Use 'in line' ducted fan, flexy ducting to fan unit from bathroom vent, flexy ducting from unit to soffit vent --- perhaps. ??