Condensation on side extension on ground floor , Pls Help

[sdugoten]

Do you have backdraught vent on the toilet extract?

Could it be the radiator leaking if it only happens in winter? Do you have a closed loop system?

Water will drip regardless if the radiator is turn on or off though. I believe it's a close loop system, there is no water tank, just a combi boiler and connect to all the radiators.

 

[sdugoten]

Like everyone else I just cannot see how enough warm wet bathroom air is going to find a cold enough surface (bearing in mind the hot waste will be warming things up) to create running water.

Is it possible that it's leaking when you have a shower, but on a hot day the drip is drying before it gets to the point it leaks through, and on a cold day it doesn't dry and runs across the ceiling somewhere and drips through? The leak point may be miles away from the drip point. This sounds far more like a leak to me than condensation.

Besides the ceiling in the kitchen drip, there is one more location that drip when I am taking the shower.

In the middle of the shower, this extract fan start water dripping. Since this is inside the bathroom and water drip down to the bathtub..so I didn't really look at the issue because water drip right into the bathtub..

Anyway, I can see water dripping right below the extractor fan during hot shower in cold winter night. I wonder if this can be the source...? However, I have no clue how these water will drip all the way to the toilet area tho...(the location where we found the water mark at the ceiling of the kitchen is about the location next to the toilet on 1st floor.