Mysterious leak!

[Ejaz]

Hi all!

I have a mysterious leak in the bathroom. The ceiling in the bedroom beneath became stained so I cut through to investigate. In the picture you can see the supply for the toilet flush going up through the floor. The surrounding floorboard is wet along with the joists and the ceiling below was sodden when I cut through.
None of the pipework was wet anywhere though! The tee joint is bone dry. I flushed the toilet and felt all around the cistern, supply and soil pipe, all dry!
I'm at my wit's end trying to figure out where the water is coming from. In the bathroom I've got adhesive flooring so I can't take it up but it's also dry to touch. I've put down a tea towel around the supply for the cistern but it's been dry.
Any ideas?!
Thanks

 

[Lower]

take a picture of the toilet above so we can see the installation

 

[just pumps]

What else is in the bathroom, water finds the lowest spot so it could have run from anywhere.
Stab in the dark but showers seem the worst for leaks so run shower for awhile and see if the damp area becomes wetter.

 

[Ejaz]

Don't have any closeups as I'm out at the moment. On the left of the toilet is the shower. I've run the shower with the head facing all the points where the doors meet the base and walls, no leaks at all.

 

[freddiemercurystwin]

Can you take the bath panel off to investigate behind there?

 

[Ejaz]

Yep had a look in there too, bone dry and no water marks at all!

 

[just pumps]

Edit; Q answered above.

 

[Stivino]

Toilet pan connector? It will only leak when flushed so flush two or three times and look very closely.

 

[Old Salt]

Try some talcum powder. Sprinkle around the area and try to get some on the underside of tbe pipes, joists if you can any damp spots will show up.

 

[Ejaz]

Cheers guys. Yeah checked the toilet in my initial investigation, did a few flushes, nothing damp or dripping around the connector.
I'll try the talc on the floor around the toilet and supply for flush as that's where the water appears to be coming from . The joists were damp to touch but pipes were bone dry.
I have a tenant in this house who is rather large so I'm beginning to suspect there may be some movement at the front of the tray where the it meets the shower door frame?

 

[CBW]

Check the toilet pan for movement, as sometimes they can leak after getting up/down.