Just moved in to a new flat with a friend of a friend. He said his bathroom is going to be out of action for a week or so while a mould problem is fixed. He is going to be charged £1300 for the pleasure, and from what he has said needs doing, I reckon I could do it for a fraction of the price (ie rent reduction) but need to confirm a couple of things.

The main problem is mould, due to having no windows and a poxy fan. He has been told they will strip the mould and paint it with a sealant to sort that, then fit a new more powerful fan.

In the past, in my old house, I did similar by scrubbing the mould with a killer, generously in order to 'soak' the walls a bit with mould killer. Once dried, I painted with a Kitchen & Bathroom damp / mould resistant paint. No mould reoccurred. Anything else I should be wary of? The bath needs resealed, too. Shouldn't be a problem.

Fans I'm less sure about. There is currently a silvervent (or something) unit. Replacing it would, I'm sure, be easy, but what with? Any recommendations? Bathroom is pretty small but opens into a hallway which has no direct window access either.

Sorry for the long post. If anyone can provide advice there's pints / favours in it as it could save me money which would currently be welcome.

Cheers

A bit tough to say without seeing it but it sounds like someon's trying to molest your friend's bank account. If we're talking surface mould on plaster that isn't a result of dampness bleeding through from another part of the building (i.e. the source is steam from the bathroom itself) then there's a day's work max for one man in the entire job. Granted it may have to be split over a couple of days to let things dry etc.

Screwfix.com's most expensive extractor is £132, no holes need cut, the electrical supply is already there as is the ducting. Easy job.

The main thing I think you need to be sure of as I say is the source of the mould. If it's internal you're laughing, stick a heater in the doorway for a couple of days to make sure it's dry then treat as you say. Fit your fan and keep an eye on it. Even if it doesn't work out it's got to be worth having a go before you splash £1300.

And if you do need to get someone in get a few quotes before you go back to Dick Turpin Builders

You are right about the cost – how much???? Clean it off the walls using a fungicidal wash you can buy from any DIY store. Repaint and get a big powerful fan put in.
However the mould is from too much moisture condensing quickly on the surfaces. You need to either increase ventilation (fan will help but some extra movement of air out of room is good – I leave my bathro door open after a shower) or increase the heat so the air will hold the moisture longer so the fan has a chance to suck it out.

I'd agree with that, looking at how the room is heated would be no bad thing.

I'd get it drying out a bit before repainting it.
As for a fan get something with a timer and wired to a door switch, if the light is used everytime then it can be wired to the light switch.

Running the fan for extra time will benefit.

Put the room size in here and find out the recommended fan size based on that.

Get something that shifts the air at a rate, ie litres per sec.

A rough guide for a bathroom is – 15 litres / second

It seems my typing is to slow, all advice is good so far.

or turn the hot water off..

Gve all your gloss paint a pollish with car wax pollish. this will fill all the micro dents in the paint so mould can't sink in so well. you can also do the tiles and any other surface thats gloss. do this evey year and any mold on the tiles, pipes or wood work will wipe off.

as said above pretty easy job.. i had exactly the same bathroom issues and a new extractor fan and ceiling repaint ended up as a complete back to studs bathroom reno… was on the cards anyway.

Our new bathroom now has mould resiatant drywall, mould resiatant paint although not nasty glossy stuff, towel warmer for heat, larger capacity extractor fan and its on a timer switch that without fail, stays on for 30 minutes after we're done in the bathroom.

1300 quid is a ridiculous amount of money for that job..unless there is mould above the ceiling and thats being completely replaced (we had some mould between the drywall and vapor barrier.. hence the new ceiling drywall). I reckon 1300 would have paid my labour on the complete reno I did.. not just a fan/repaint job!

Most important thing with the fan is not the power, but the type.

What is the ducting like that takes the condensation out of the bathroom? I am assuming that as there are no windows, then it is a fairly long piece of ducting to an outside wall/roof?

The house I live in has the bathroom on the 'middle' and so the ducting is about 4-5m and goes up into the roof space.
Our old fan failed and her indoors' dad came & fitted a new fan. It was a fairly cheap axial fan and while he thought it would do the job I wasn't so sure.
2 months later, and we have mould appearing on the ceiling – even a short shower resulted in a complete steamy fog in the bathroom.

For extended runs of ducting you need a CENTRIFUGAL fan, not an AXIAL one. An axial can provide lots of air movement but at low pressures, whereas the centrifugal can't shift as much air, but can cope with a higher pressure. With lots of ducting and an axial fan the resistance means you probably actually get no flow, and hence really bad mould from all the damp air.

I replaced the axial fan with a centrifugal Manrose (or monrose?) fan for about £45. It now keeps the bathroom vitually condensation free – the mirror steams up, but there is no wet mist in the air and as soon as you stop showering you can actually see the air clearing up.

Another thing to consider is a slight air gap around your door. If the door fits too well & there is nowhere else that air can get in to replace the air that the fan is trying to remove, then the fan has to work harder to move the air. Our door has about 5mm gap at the bottom to let the air in to the room freely.

Most important thing with the fan is not the power, but the type.

The second most important thing is the position – put the fan in the wrong place and it simply won't shift the damp air.

good grief. I had to come back to this because I'm still amazed…

yesterday the guy turned up to start the work. He took the front panel off the bath to establish the source of moisture (this hadn't been done BEFORE giving the quote). Turns out just to be condensation on the cold water pipe which was soaking into the plaster and growing a mould patch on the other side in the hallway. Pipes lagged, all done.

He then cleaned the walls of mould – nothing more than light surface mould, took off two pieces of wall paper which were peeling off and prepared walls for painting (2 little bits of filler).

Now he just has to repaint, change the fan and reseal the bath.

To recap, all this for £1300 and flatmate decided not to let me do it for 1/3 that as my work wouldn't be guaranteed. Doesn't seem like an awful lot to guarantee to me… I'm definately in the wrong job.

Oh, and the guy arrived today as I was leaving. He's about 12.

Changing the fan is possibly a job for a PartP qualified sparky (i think), because of where it is.

To recap, all this for £1300 and flatmate decided not to let me do it for 1/3 that as my work wouldn't be guaranteed.

And if the mould returns he'll claim it's due to another source and nothing to do with his work. Guarantee's not worth a damn seeing as this guy's an obvious cowboy.

A fool and his money and all that. 🙄

I have a damp bathroom. The extractor fan hole doesn't have a proper vent outlet but goes out to a brick sized air-brick, so only little holes.
Was thinking of getting a builder in to re-cut the outside hole to be a 100mm square.

Also thought about centrifugal fan but some axial fans have a bigger output, but noticed centrifugal fans are better for long ducts.

If I went for a centrifugal fan would that cope with the air-bricks resistance to outbound airflow, or would just getting the outside of the vent re-cut be fine with an axial fan?

Pieface – does your axial fan pipe go straight into the air brick or do you have a load of ducting in between?

If the fan is very close to the outside, with just an air brick in the way, it might just be worth getting that sorted. I don't really know that much about this kind of thing, but you can probably get the air brick cut out & get a slatted cover put in place.

Unless you have a massive bathroom, I would have thought that a decent centrifugal fan would provide plenty of flow for you & they do cope better with more resistance in the flow path. A 3x3m bathroom is only about 18m^3 and I think our centrifugal fan manages 110m^3. It's a Manrose CF200 – not very pretty but does the job.