Bathroom ceiling mouldy

[vw754]

My bathroom ceiling is mouldy I do have a 150mm blauberg extractor fan but it doesn't help much , bathroom is 6 feet square.
I will at some point get a inline fan mount it in the loft ( and make a hole in the wall or soffit to extract) and fit the grill to the bathroom ceiling at the moment it's straight out of the wall .
Instead of painting with mould paint , I was thinking of putting a sheet or something on the ceiling that's water proof to hide all the black.....any other suggestions?

 

[Wayners]

Lack of insulation above maybe.
The plasterboard gets cold and the warm humid air dumps the moisture on the ceiling..
A warm ceiling wouldn't get any condensation on.
If you stick your hand under the insulation it should feel warm

 

[vw754]

Plenty of insulation above

 

[Jurassicspark]

Resolve the mould issues first then fix the damage done.

 

[Wayners]

Do you get condensation on windows in the house.
Also mould in other rooms?

Buy a humidistat meter as under £10, find out what's going on

 

[vw754]

The rest of the house is mould free , no condensation anywhere else , plus windows are a year old too , just the bathroom it was ok until we fitted a combi shower.

 

[Murdochcat]

Do you have enough airflow under the door ? Keep the window shut

No point in having a fan without sufficient airflow from within the home

 

[vw754]

Bathroom is upstairs and when I moved in I had loft insulation put down , however the loft is cold at this time of year as it has no felt just old style bodging

 

[Harry Bloomfield]

My bathroom ceiling is mouldy I do have a 150mm blauberg extractor fan but it doesn't help much , bathroom is 6 feet square.

I will at some point get a inline fan mount it in the loft ( and make a hole in the wall or soffit to extract) and fit the grill to the bathroom ceiling at the moment it's straight out of the wall .

A 150mm, straight out of the wall, in a 6 feet square bathroom, ought to be perfectly adequate. You say the ceiling above, is well insulated - that only leaves the fan not working, not working well, or not being on when the bathroom is in use.

Is the fan PIR controlled, on a timer, or only comes on with the bathroom light? Are users of the bathroom, forced to turn the light on when it's in use?

Try the tissue test - with fan running, see if it will hold a sheet of tissue to it.

[EDIT] I missed - air needs to be able to get in, to replace that sucked out. Either bathroom door open, or a decent gap below bathroom door, and fan left running, for 20 minutes, after the room is evacuated.

 

[Koolpc]

Ventilation, ventilation, ventilation...

 

[Wayners]

You need a 10mm gap under the door to allow air in and a good extractor. Keep the dryer air coming in and moist air going out.
Not realistic to expect window to be open every time you shower. I used to open the front and back door for 10 mins during winter to let in fresh dry air. It did help however, It's the most stupid and ridiculous advise tbh. So is opening bathroom window. Cold air rushes in condensing the moisture. Place is running in water. It's impractical! We all just create so much moisture now in modern houses.
I'll guess the level of humidity is high to start with so no insulation or ventilation will cure the problem hence I said spend £8 on a meter to see what's going on. Then decide how to tackle it.

We run 2 small dehumidifiers for a couple of hours every evening pulling about 6lts of water every week out the air.
I think the cost is about £1 week during winter to run both. Real game changer for us.

See what the humidity is by testing. Decided how to deal with it.
When you get it' under control and dry maybe paint bathroom ceiling.

 

[Harry Bloomfield]

We run 2 small dehumidifiers for a couple of hours every evening pulling about 6lts of water every week out the air.
I think the cost is about £1 week during winter to run both. Real game changer for us.

Any time you run a dehumidifier, it will suck moisture out of the air - moisture is a normal thing to have in the air, at all times. The important thing, is the level of moisture - too high, and it condenses out on cooler surfaces.

The only use I make of the dehumidifier, is in the utility room, where clothes are hung up to dry, when - on those rare occasions, they cannot be hung outdoors.

See what the humidity is by testing. Decided how to deal with it.

I aim for 60 to 70% RH generally, but it can temporarily, and briefly rise to 80%, without causing issues. 61%, indoors at the moment, 93 outdoors.

 

[JohnD]

just the bathroom it was ok until we fitted a combi shower.

These cause a huge amount of hot steam, so you need to increase the ventilation accordingly

I do have a 150mm blauberg extractor fan but it doesn't help much ,

When do you turn it on, and when do you turn it off?

Show us a pic. And of the vent on the outside of the wall.

Is 150mm the diameter of the duct, or the size of the indoor casing?

 

[RandomGrinch]

As with all mould problems, there can be many factors at play.
So far ventilation and insulation have been covered.
But, how is your bathroom heated?
It may seem like a rigmarole, but having the room (and in turn, it's surfaces) at a decent temperature, before having the shower, can help avoid condensation. More vapour can be contained in warmer air, thus any extraction will be more efficient in removing vapour, per unit volume of air moved.

 

[Jurassicspark]

My bathroom ceiling is mouldy I do have a 150mm blauberg extractor fan but it doesn't help much ,

Have you checked if the vent isn't clogged up?

When was it installed? As John mentioned above, show a picture of the vent on the outside.