Bathroom extractor fan mounting

Forums › Home Workshop DIY › Bathroom extractor fan mounting - any rules?

Xile

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#311138 17-Dec-2023 13:09

I recently had a bathroom renovation. One bathroom split into two. Extractor fans installed as expected. I noticed that they appeared quite loud so went up into the roof space to have a look. The way they have been mounted, well, seems quite amaturish and is probably the reason why they are quite noisey.

My questions are: are there any rules around how they should be installed? Even if there aren't does this seem acceptable?

Thanks

SomeoneSomewhere

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#3172671 17-Dec-2023 13:38

I'm not sure how you expect them to be mounted - an electrician is unlikely to install extra timber, and they appear to be screwed in place. There are no rules that I can think of that would have an impact.

Duct silencers, anti-vibration rubber mounts, and mounting them to the roof instead of the ceiling or via suspension are all options, but it's going to cost you more and wouldn't be the default.

Flexible duct is terrible but typical.

tweake

2391 posts

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#3172744 17-Dec-2023 15:23

afaik no rules. as long as it rated and sounds like its working it passes. it if actually does the job its meant to do is up to you.

a fan like that should be suspended. also the bends are poor and of course the insulation not put back. noise can be made worse by restriction due to bends etc. not sure of thats two ducts or the same one twisted over itself.

frankly for most people bathroom fans and rangehoods are a "tick box" exercise. have a look at how they are done in many "award winning" homes, typically the barest minimum and done badly. as long as it ticks the box, who cares if it works. </rant>

larknz

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#3172747 17-Dec-2023 15:29

The best way to reduce noise is to suspend the fan. Attaching directly to timber will tend to amplify the noise.

Rickles

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#3172748 17-Dec-2023 15:34

When I did mine some years ago, I too found noise and vibration to be a touch much, so screwed a timber crossbeam to rafters and placed 5mm solid rubber mat under them.

I also mounted the inlet and outlet in straight line from bathroom/shower ceiling to outside wall (actually went out through soffit).

Sometime later had electrician rewire new heat lamp/extractor fan unit, and he said the mounting was great idea. Then packed insulation under hoses and motors.

Xile

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#3172755 17-Dec-2023 16:07

SomeoneSomewhere:

I'm not sure how you expect them to be mounted - an electrician is unlikely to install extra timber, and they appear to be screwed in place.

Funny you say that. There was actually a perfectly good piece of plywood next to this location where he could have made a nice platform. Instead he threw the wood in the skip!

Xile

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#3172756 17-Dec-2023 16:11

tweake:

a fan like that should be suspended. also the bends are poor and of course the insulation not put back. noise can be made worse by restriction due to bends etc. not sure of thats two ducts or the same one twisted over itself.

I like the idea of suspending them. Any suggestions on how to do that. Some hooks and some zip ties? Or something more robust?

BTW there are two extractors close to each other but they are twisted somewhat.

tweake

2391 posts

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#3172758 17-Dec-2023 16:16

Xile:

tweake:

a fan like that should be suspended. also the bends are poor and of course the insulation not put back. noise can be made worse by restriction due to bends etc. not sure of thats two ducts or the same one twisted over itself.

I like the idea of suspending them. Any suggestions on how to do that. Some hooks and some zip ties? Or something more robust?

BTW there are two extractors close to each other but they are twisted somewhat.

zip ties will work. there is proper duct hanging strapping available.

Sharesies

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SirHumphreyAppleby

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#3172760 17-Dec-2023 16:23

Xile:

I like the idea of suspending them. Any suggestions on how to do that. Some hooks and some zip ties? Or something more robust?

I supplied some wire rope to suspend a fan once. The electrician advised against using that as it could eventually fail with the fan moving around when in use. Instead, he used some scrap wire he had in his van. This was insulated and I assume solid core.

SATTV

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#3172761 17-Dec-2023 16:29

Xile:

tweake:

a fan like that should be suspended. also the bends are poor and of course the insulation not put back. noise can be made worse by restriction due to bends etc. not sure of thats two ducts or the same one twisted over itself.

I like the idea of suspending them. Any suggestions on how to do that. Some hooks and some zip ties? Or something more robust?

BTW there are two extractors close to each other but they are twisted somewhat.

In my last house we used paracord to do this, cheap and will last a very long time, the fan dangled quite nicely from the frame ( we did not have trusses ) remember to have a clearance so there is no fan touching the wood, if I recall I used a large eye to screw into the wood to hang the fan from.

John

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