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Bathroom mould. Prevention advice?


TableLeg

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Anybody have experience of dealing with mould on a bathroom ceiling?

 

I have a high flow rate extractor fan to the outside of the home. The property is a bungalow so therefore the loft roof space is above the bathroom. There is approximately 100mm thickness of insulation above the bathroom. The bathroom walls are tiled from floor to ceiling. After showering I can see condensation running down the tiles.

 

Heating wise there is a heated towel rail on the central heating.

 

Anyone have any suggestions?

 

My next step is to paint the ceiling with some anti mould paint and see if that helps.

Or I've considered if I should add more loft insulation, adding more heating and also another extractor fan...........

 

Hope somebody on here may have some useful advise to remedy this issue.

 

Thanks in advance.

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I would consider adding an extractor fan to remove the steam when you shower, the steam created has to go somewhere the nearest cold surface it can condense on seems to be the place at the moment. I'm no building expert but this is what i found worked well in our little shower room.

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1 minute ago, Rusty Nuts said:

I would consider adding an extractor fan to remove the steam when you shower, the steam created has to go somewhere the nearest cold surface it can condense on seems to be the place at the moment. I'm no building expert but this is what i found worked well in our little shower room.

Hi,

Do you mean a 2nd one?

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I fitted a fairly large duct fan in the loft space above the bathroom in my place. It shifts a lot of air (will draw the door shut if left slightly ajar) and is really quiet too. Similar setup I imagine, bungalow, walls and floor tiled, a large towel rail (about 6’ tall) and underfloor heating too. 3 years since I did the bathroom and no sign of mould, thankfully! Had a persistent problem with mouldy ceiling in my last place, but that was tricky as it was a dormer and the bulk of the ceiling was barely insulated at all, with little or no prospect of doing anything about it.

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37 minutes ago, corsechris said:

I fitted a fairly large duct fan in the loft space above the bathroom in my place. It shifts a lot of air (will draw the door shut if left slightly ajar) and is really quiet too. Similar setup I imagine, bungalow, walls and floor tiled, a large towel rail (about 6’ tall) and underfloor heating too. 3 years since I did the bathroom and no sign of mould, thankfully! Had a persistent problem with mouldy ceiling in my last place, but that was tricky as it was a dormer and the bulk of the ceiling was barely insulated at all, with little or no prospect of doing anything about it.

Thanks Chris,

I currently have a high flow 5" extractor specifically purchased due to it's high flow rate. Do you have any info on the fan/type of fan you used?

I don't feel that the current heating setup is sufficient. I planned to install underfloor heating but just haven't got around to it. I feel that the bathroom is not overly warm and that probably doesn't help. 😕

Edited by TableLeg
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Sorry what I meant was a stronger fan, having a warm room would also help when we changed the rad in the bathroom the plumber said not to go for a towel rail as they don't give off much heat - he referred to the heated mirror analogy which doesn't get steamed up. I don't know what make and model we have but it does the job.

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4 minutes ago, Rusty Nuts said:

Sorry what I meant was a stronger fan, having a warm room would also help when we changed the rad in the bathroom the plumber said not to go for a towel rail as they don't give off much heat - he referred to the heated mirror analogy which doesn't get steamed up. I don't know what make and model we have but it does the job.

Thanks RustyNuts, :yes:

Thing is I bought a high power fan especially for the job, so apart from adding another fan I'm not sure I'd gain much by replacing it.

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This one Jared:  https://www.tlc-direct.co.uk/Products/SLTD350SILENT.html  A 5" unit.

 

With a timed PIR sensor over the door so it looks after itself. I did also buy a humidistat to go in parallel but the case was hideous! Couldn't bring myself to put it on the wall.

 

I put the outlet duct in the ceiling, over near the shower, so it tends to draw the air from there. Inlet to the room is via the door. Outlet goes through the wall in the loft to outside with an an anti-reverse flappy vent thing (that bangs on windy days).

 

On an extremely cold day, there is some dampness on the extreme corners of the tiled wall on one side (a partly external wall) but none on the ceiling. Also get some on the window as well of course. The biggest external wall has a good thick layer of additional insulation on it - I should have done the same on the other wall too I suspect, although it hasn't been a problem.

 

There is a good layer of insulation under the heated floor too. I didn't enjoy doing the prep for that!

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As a building surveyor, I would recommend insulation, heating and ventilation. Nothing much you can do about the walls but increase the insulation above. Better towel heater or radiator. A humidistat fan would be best. It will deal with condensation without timing out. 
To deal with existing mildew, Detol do a mould and mildew killer. Bleach is also effective but obviously be careful. Don’t cover it up without killing it as it will simply come back. If you have plastic windows, open the trickle vents and leave them open. 
Not a magical fix but best you can do. 
Good luck

 

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Thanks Chris,

The one you linked to is the newer version of the 5" one I already have. My outlet duct is directly above the shower cubicle too.

 

I can't help but feel the heating is insufficient, the towel radiator is quite big but doesn't really seem to add much to the overall heat of the room. In hindsight I should have fitted a wall radiator (having recently looked at them). Trouble is there is only 1 wall big enough to take it (the bathroom is not very big) and that wall currently has the bathroom wall storage unit on it. I can't really see anywhere else to put the bathroom storage if I were to move it.🙁

 

 

 

 

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6 minutes ago, AndrewBClarke said:

As a building surveyor, I would recommend insulation, heating and ventilation.

Thanks Andrew,

So you would suggest more insulation in the loft space above the bathroom in the first instance?

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I have had to sort this type of problem out for many landlords with flats.

Normally condensation and then mould forms were there is an issue with ventilation, with flats the occupiers would leave the properties all day without heat and with all windows/doors closed. Even with extractor fans there will be dead areas that do not circulate the air and so promote stale air. Solution is to get these dead areas to circulate, therefore the balance is to get heat, ventilation and circulation into the affected room.

Easiest way is to open a window, if this is not possible you may have to change the position of the forced ventilation (in the ceiling is advisable), heat is also required and certainly 100mm of insulation is not up to modern requirements now being a minimum of 200mm or equivalent value.

Where opening the windows was impracticable I set up "positive atmosphere" fans in the loft to make sure the premises changed air regularly with special regards to any dead areas.

This sort of problem is very common but easy answers are not straight forward, either the assistance of a certified specialist(who will have to visit to access) or a matter of trial for fans, insulation, heating, ventilation etc. will be needed. Treatment of the mould will be best with good quality treatments but only after the cause of the problem have been removed.

Hope you solve it soon,.

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Ah, fan probably up the job then!

 

I went totally OTT with the towel rail as I expected it would have a job to do. The bathroom is small so only about 300W of underfloor IIRC. Towel rad is chromed which dramatically reduces the output over an enamel finish so I went for the biggest one I could fit in the room. 

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Generally heating in a small bathroom is not an issue when there is adequate heating in the rest of the building. What is important is adequate ventilation(especially in rooms where water vapour is produced) because insulation, building materials etc. have virtually made buildings airtight.

Not that many years ago central heating was only for the rich, ventilation fans only for factories, and steel framed window were normal (let alone double glazing).

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