Box gutter leaking at down pipe

[ash_scotland88]

Garage roof is leaking.
It's flat felt roof with a box gutter with an internal down pipe and WW pipe runs down the internal wall of the garage.
For whatever reason the gutter is raised around the downpipe meaning the water sits in the gutter and presumable saturates the felt which is causing a leak.

Is there a DIY solution or am I better getting in a roofing expert?
Quick exploratory on the roof wasn't aware what has caused the raised part, if it's something underneath or sinking of the rest of it.

[jfb]

some good photos would probably help

[ash_scotland88]

The downpipe cover was acting as a damn itself, I've now raised that up so atleast some water can get away.

https://ibb.co/5F30JST

https://ibb.co/tbmZtxt

https://ibb.co/vQcD6s9

https://ibb.co/CPmnMNp

 

Can hopefully see the raised part before the downpipe, as a note a wet roof shows off all the imperfections.

[Mr Punter]

I would get rid of that arrangement and have an external gutter and downpipe.

[ash_scotland88]

On 26/05/2021 at 19:11, Mr Punter said:

I would get rid of that arrangement and have an external gutter and downpipe.

That is probably the best way but by no means practical. Down pipe and drain is inside the garage, 3ides are built into a hill and would struggle there. Front is straight onto pavement and doubt the council would appreciate it.

 

[Mr Punter]

Where does the downpipe connect to internally?  Can you not excavate to connect to the same pipe underground but have an external gutter and downpipe?