Downstairs toilet ceiling issue

FIREDreamer

Could anyone tell me if this is mould or ghosting? The room above has no issues on the flooring that we can see. Can it just be painted over? Thanks.

rob7475

Does the room suffer from condensation at all? Do you have an extractor or a window that is opened after bathing / showering?

Looks like mould possibly from condensation to me. I'd clean it up, paint over with Zinsser BIN to stop the stains coming through your new paint, followed by a decent paint with mould inhibitor.

grumpy_codger

If it's just a toilet and the ground floor, I don't see any real reasons for condensation.
And I don't think that any stain blocker is needed for mould.
IMO, it's worth removing the light fitting and inspecting the void at least with your fingers, but better with an inspection camera.

ThisIsWeird

Yes, worth inspecting the ceiling void - if it's empty - good chance - then there could be a howling breeze going through there from the wall cavities, so that will be a very cold ceiling, prone to condensation.

I would remove that light fitting, and use an endoscope or even a small mirror to examine the other side.

FIREDreamer

rob7475 said:

Does the room suffer from condensation at all? Do you have an extractor or a window that is opened after bathing / showering?

Looks like mould possibly from condensation to me. I'd clean it up, paint over with Zinsser BIN to stop the stains coming through your new paint, followed by a decent paint with mould inhibitor.

It’s just a downstairs toilet with a carpeted bedroom above it. The ceiling in that bedroom had ghosting which has not reappeared since the roof above it was replaced a few months ago.

grumpy_codger said:

If it's just a toilet and the ground floor, I don't see any real reasons for condensation.
And I don't think that any stain blocker is needed for mould.
IMO, it's worth removing the light fitting and inspecting the void at least with your fingers, but better with an inspection camera.

Just a toilet and sink. Plus lots of junk stored on top of the built in slider wardrobe (for want of a better description). There was mould or mildew growing on the window but I got rid of that.

ThisIsWeird said:

Yes, worth inspecting the ceiling void - if it's empty - good chance - then there could be a howling breeze going through there from the wall cavities, so that will be a very cold ceiling, prone to condensation.

I would remove that light fitting, and use an endoscope or even a small mirror to examine the other side.

Light fitting I don’t think I can remove. There is no issue on the floor above it. There is no leaking radiator there for example.

EDIT: We had that cavity wall ball bearing stuff put in about 10 years ago. Mould has been a bigger issue since.

FIREDreamer

These are the before and after pics of the window.

ic

Sounds like you're not ventilating your house well enough.  Prior to the cavity wall insulation, moisture present in the house (from you breathing, baths and showers, hanging out washing, etc etc) will have condensed on the cold walls throughout the house (and not been a problem as it was essentially thinly spread everywhere).  Now those walls aren't as cold, so the moisture condenses on the fewer cold spots that remain - your window, and the ceiling in this case.

You could get a hygrometer and measure the humidity around your house - if its towards 60% your house is damp, you want to aim for 40%.

Do you ventilate the bathroom when having baths or showers to clear the humid air?  (do you have an extractor fan and actually use it, or do you keep the windows open).  Are you heating the house (warm air holds moisture better than cold)?  Is this downstairs loo heated?

I agree with others, it sounds like the void between the two floors could be cold, making that ceiling cold, which attracts the damp.  In my own house I found some seriously draughty points and sealed them up.

A dehumidifier could be used to pull moisture out of the air.

Doonhamer

Maybe buy some of that gloss white silver edged plastic paneling, it's really cheap and you just need to silicone it on and silicon bead round the edge

FIREDreamer

ic said:

Sounds like you're not ventilating your house well enough.  Prior to the cavity wall insulation, moisture present in the house (from you breathing, baths and showers, hanging out washing, etc etc) will have condensed on the cold walls throughout the house (and not been a problem as it was essentially thinly spread everywhere).  Now those walls aren't as cold, so the moisture condenses on the fewer cold spots that remain - your window, and the ceiling in this case.

You could get a hygrometer and measure the humidity around your house - if its towards 60% your house is damp, you want to aim for 40%.

Do you ventilate the bathroom when having baths or showers to clear the humid air?  (do you have an extractor fan and actually use it, or do you keep the windows open).  Are you heating the house (warm air holds moisture better than cold)?  Is this downstairs loo heated?

I agree with others, it sounds like the void between the two floors could be cold, making that ceiling cold, which attracts the damp.  In my own house I found some seriously draughty points and sealed them up.

A dehumidifier could be used to pull moisture out of the air.

First paragraph is a good explanation- thanks.

I have a hygrometer is six rooms. The temperature is around 18-22 Celsius and humidity varies from 39 to 55. I might put one in the downstairs bog to see what it reads.

We don’t ventilate the upstairs bathroom enough I suspect. There is mould on some sealant there but ceiling has a plastic false ceiling and is okay. I use the shower in the ensuite which has an extractor fan and is showing no issues. Have a small dehumidifier in the master bedroom.

There is mould on the landing window lintel and sealant but I cannot reach it, it is above the stairs going up so even getting a ladder and putting it there is going to be difficult.