Damp patch in ceiling

[Remmy123]

I have attached a picture of a new leak - thiS pic is taken from the ground floor. Above me is a bathroom.

We have looked under the bath and it is dry.

Directly next to the bath (area where leak is) is a radiator and I think it might be the radiator leaking as the damp patch is warm (so warm water/warm pipes) it doesn't feel damp.

Any ideas what it can be? It isn't progressive so something that isn't leaking constantly.

Ive turned the valve off on that radiator to see if leak then dries out (or does hot water continue to rub anyway in pipes)

I do need a plumber but haven't got any money until end of month.
Many advice welcome, thanks

poke a hole in it with a skewer or something so any water can drip out. After repair, it can easily be filled before repainting.

rub your finger in the water. Does it have a chemical odour, like when you bleed the radiators? Or is it soapy? Or clean?

Can you see any water round the radiator, especially the valves or end plugs? Or is it rusty along the bottom seam?

if it is a pipe in the floor, it will drip even if the radiator is turned off.

what are your floors made of?

Thanks piglet john

It's a tiled bathroom and it's a Victorian house

I've attached a pic under the radiator which is rusty? Is that what you meant by Seam?

The valves and pipes are not wet so it's underneath

Thanks

Ps no water or leak can be seen in bathroom

yes, that looks like a rusty bottom seam. The metal front and back of the radiator are welded together underneath and down the sides, sometimes also along the top. Sometimes the seam leaks and rusts, especially if the radiator is often cold in a steamy bathroom so gets condensation.

It can also happen, especially if the boiler is unpressurised (usually old) wih a small feed and expansion tank in the loft and there is a defect causing the water to become aerated. This usually also means the radiators need frequent bleeding. Less often there is a faulty weld that somehow crept through quality testing.

Sometimes, there might be a leak at one of the end plugs, and the drip is tracking down under the rad.

Rub the seam with a clean dry piece of kitchen roll. also the two bottom corners with separate pieces. Which has the most rust marks and/or damp?

No damp from the seam - no water at all coming from the rad that's visible

If you have no water visible in the bathroom, it sounds more like you have a leak under the floor. How easy is it to get access to under the bathroom floor? What you may also find, is that the leak is nowhere near where the signs of it are. It may very well be coming in from outside, if it is intermittent, or from a waste pipe.

Hi no access unless I rip out ceiling underneath?

Ah. Doesn't sound like it's gonna be easy. If you can get hold of an inspection camera, it might help you trace it, but it definitely sounds like you need a professional to look at it. I would suggest checking all your water connections. As PigletJohn suggested, get a piece of toilet paper or kitchen towel and run it around each join from the bottom of the tap to the pipe. Should allow you to eliminate all the obvious first.

If you notice that the ceiling is getting wet or the spot is getting bigger or if the ceiling has quite a bit of give when push with your finger your ceiling is in danger of caving in. I was house sitting for my neighbor and noticed something like this so I touched it and the whole panel fell down with a gush of water. Depending on the material, when the water is dripping slowly the panel can get over saturated. It then can collapse. The leak was from the upstairs bathroom, but not directly above the spot on the ceiling...the water from the leak was dripping down the horizontal pipe under the bathtub faucet and was going to the lowest point and dripping from there because the pipe wasn't completely level. Good luck. Maybe poke the hole in the ceiling like a pp suggested (and put a bucket under it if dripping)so the water won't bleed throughout the ceiling material. That may give you some time until you can save up..it's not really an emergency right now unless water is gushing out. Good luck!
Please excuse typos

Your home insurance might cover you. Call them to check. Some policies also have a cover called something like 'track and trace' which looks for source of leak. Insurance companies are always looking for ways out of claims so don't let it go on any longer before calling or they will say you didn't tell them soon enough and not help. They also won't cover things like poor workmanship causing leak. Needs to be something you couldn't have known about which went wrong. Good luck!

Thanks all - the patch always feels dry but I think it's the radiator quickly drying it out.. it's also not getting bigger, it must be something that is intermittent which makes it more odd

It was the bath above the sealent had come away so water from
Shower was running down the wall and under the bath