Shower Room Ventilation

6 Oct 2006
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United Kingdom
Hi All, hope I am posting this in the right section..........

My bathroom/shower room has always had a condensation problem as it is very small with no external windows. There is a small extractor fan adjacent to the shower but still the room steams up and this is now causing mould etc to grow on the walls/ceiling.

Now I am wondering before I go to the effort of replacing the fan if there should be a vent somehwere in the room to let the air in....there is no space above the door to ceiling so will have to be in the actual I best placing this at the bottom or the top of the door...?

Any help gratly appreciated as it will save the wife from having to de-mildew the walls so often!
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Door should be undercut by 10mm, but this may not cure the problem. Its an ongoing issue with inner rooms with no windows, weedy extractor fans just aren't up to it. No great solution other than a beefy extractor.
also, you need the fan to carry on running until all the steam has been cleared and the wet towels and tray have dried off. this can take quite a long time. You can get a fan with a timer or humidity stat.

Radial fans are more powerful/quieter usually.

It is easier in a bathroom where people go in and out all day to wash their hands or use the WC, turning on the light and operating the fan each time.

Also, check that the duct and the outside grille are not choked with dust and cobwebs.

The gap under the door is best as this will allow cool dry air to enter, while the hot moist air rises towards the extractor.
Thanks for the help guys. ...

I am fairly certain it is a budget axial fan installed by the previous owner and as far as I can recall it vents into a plastic pipe that then appears to go all the way to the roof in a pipe chase( another 2 storeys).

Suspect this means that the fan is too feeble to extract anything much and so is making the problem worse...

Will have a look at trimming the door and upgrading to a beefier radial fan..

The fan itself is within reach when you are standing undr the shower....does this mean I need to use a low Voltage version for safety or can you get ones with sufficiently high IP rating for use n the wet zone?
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Theres the problem then, most extractors only need to pull the air a few feet. I'd be fitting a powerful inline fan in the roof space, sucking air up the pipe. Does the existing extract to the outside?
I believe it does but have never ventured up the pipe chase to the ladders in there look a bit far as I can see the pipe goes all the way to the roof so I assume outside...will need to get onto the roof and have a look or get the rope access gear out and go for a climb up the chase..!

Will have a look tonight if I can and oonce I have all of the facts I will probably be back on here to get the best suggested solution.

Thanks again
Its an old Villa converted into 4 flats so they have bricked off a section to the rear of the bathroom (roughly centrally in the building) for all of the services...there are a lot of cables pipes and even the odd earth bond in there for the plumbing! Even found a discarded sheet of Asbestos a while back!
I call it a chase but I suppose it is more like a shaft, about 6 feet long by 3ft wide and runs from basement/ground level to I assume the roof. ( we are on 1st floor effectively at that point). There is a series of timber ladders up to the roof.

I will have a check tonight but from memory it is about 150mm rigid plastic pipe (similar to that used for waste water outlets) and it appears to also serve other flats as it runs down to the basement flat also...?

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