Very damp bathroom - any solutions?

[thanksamillion]

We have a terraced house with a flat roofed extension on the back with a large (and I mean big) bathroom. It's rented out at the moment as we're overseas and the tennant has complained about it being damp. We know it's a problem (condensation rather than any other type of damp) and want to do something about it but don't know what to do.

We put in an extractor fan but that doesn't seem to have made any difference. The agents have suggested something called a 'Positive air system'. Has anyone heard of this or have any other brilliant suggestions?

Does it have a window ? Are the tenants actually using the extractor fan ? Does the room have anti mould paint on the walls ? If not try that as it does help with mould caused by condensation.

That was my question as well! I think they are using the fan (afaik it's one that comes on when the light does). I don't think they open the window much as it's a ground floor room and they seem worried about security.

Anti mould paint is a good idea, but they complain about the shower cubicle too. It's hard to know how much it's just that they don't clean/ventilate enough and how much it's a genuine problem .

we use this for our very damp bathroom, it helps

dehumidifier egg

some people don't like turning extractors on. Since a typical extractor is 20Watts and will run for 50 hours on 1kWh of electricity costing 14p, there is not much sense in it. Sometimes it is because they find the fan noisy

If the fan is lacking in power, get a new, more powerful one. Centrifugal fans are generally quieter and more powerful than axial fans.

You can also get fans with a timer-overrun so that, after the person has finished in the bathroom, the fan continues to run for up to 20 minutes to remove the water vapour coming from wet towels and shower. You can also get a fan with a humidstat that automatically comes on when the room is steamy. However unlike one that comes on with the light switch, it will not keep the bathroom fresh when the WC is used.

An extractor is more effective if the door and window are shut. Verify that it is spinning and the fan, duct and outer grill are not choked with dust, fluff and cobwebs.

The cheapest bathroom fans usually extract about 80 cu.m per hour, which is not much but will do if they are run for long enough.

You can get more powerful extractors that go in the loft, sucking through a grill in the bathroom ceiling and blowing the steam through trunking which goes outside through the eaves, soffit, wall or roof (it must not be allowed to blow steam into the loft)

Here are some examples

90m³/hr

one with timer

245m³/hr to go in loft

Thanks for the replies!

The egg looks good but I'm wondering if the tennant would bother to renew it when it was full - I suspect they might contact the agent and tell them it's not working - they did once call them because a light had gone .

I'm going to go back through my records and see what kind of extractor was put in armed with your info Piglet.

The anti mould paint ensures the walls stay wet all day if the room isn't being aired/dried at all, tis grim....