Damp patch above shower - ventilation issue or leak?

[Emerol]

Hi,
I live in a first floor 1960s flat with concrete ceilings and floors.

I have a damp patch with flaking paint above my shower where the paint is peeling.

I suspected it was due to the lack of ventilation in the room - there is no window or extraction fan.

However a handyman (who installed his own kitchen, bathroom and central heating) who lives in a similar flat on the street and has been doing some work for me told me it was definitely a leak.

So I approached my neighbour whose bathroom is above mine - long story short she said she got a plumber out and he scanned her bathroom and surrounding rooms with a leak detector and said there was no leak. She said he did a report which she would email to me.

It’s been over 3 weeks and there is no sign of the report. I also asked for her plumbers details so I could ask him to help me get to the bottom of it but there’s been zero communication from her.

I have reason to be suspicious - she denied the leak was coming from her place even before she (supposedly) got her plumber out.

Meanwhile I tried to get another plumber out and when explaining the situation he said it was more than likely a ventilation issue. He advised putting a small hole in the ceiling to see if moisture would leak out. I did, and it didn’t. The ceiling feels cold and there is water discolouration where I flaked away the paint but no signs of an actual dripping leak.

All good, right?

Until I had a bathroom/kitchen specialist round today (who used to live in the building) and says he’s pretty sure it’s a leak.

I am unsure what to do. The plumber I contacted didn’t actually come out - he said there was little point as he was pretty sure it was a ventilation issue.

In other news, I have a serious leak in the wet room floor and the entire bathroom needs to be ripped out anyway .

Any thoughts, insights gratefully appreciated.

Thank you.

 

[dilalio]

If you scrape some paint off and the background is dry/stain free, it's condensation. Most likely as you have no ventilation in the room.

 

[Emerol]

Hi, thank you.

It’s dry but there’s definitely a water stain.

Thanks.

 

[dilalio]

Some photos would probably help.

 

[JohnD]

there is no window or extraction fan

Then of course it is damp.

Even if there is no leak, it will always be damp.

Fix that first.

 

[Madrab]

As others have suggested .... If you have a concrete slab ceiling and a shower directly below it with no ventilation then the slab will absorb some of the moisture and retain the dampness.

If there isn't a leak upstairs and their floor is dry (and no pipes are embedded in the slab) then chances are there won't be a leak.

Remove anything covering the ceiling ( paint etc) and leave the door wide open any time the room isn't being used and see if it dries out. Another trick to test if it's surface damp is apply some heat to the slab to get the surface to dry out and see if it returns before the shower is used again.

 

[dilalio]

Hi, thank you.

It’s dry but there’s definitely a water stain.

Thanks.

Does your mirror steam up?
I know it does.
So will other surfaces...
It's called a dew point.

 

[Emerol]

Thanks everyone. Here are some photos.

@Madrab my neighbour would not have a damp patch on her floor as the pipe is underneath her floor.

I removed the paint a week ago and I can't feel any damp there now but the water stain remains.

I'll put some damp proof paint on it and see what happens.

I'll also get an extractor fan put in the bathroom when I get the major work done and hopefully that will solve the problem.