Lead "stitching"?

[Zebra]

My new roof finishes inside a gable wall with an upstand. The roofer will be doing the lead work to bring the rainwater round inside that upstand, and the builder tells me that the lead will have to be "stitched" to make it one piece, rather than simply overlapping several pieces of lead. (Between you and me, I'm not sure whether the roofer knows what the builder is on about...)
Can anyone tell me what this means, to "stitch" lead?

 

[Flyfisher]

The short answer is 'no' but there is a lot of information about leadwork here: http://www.britishlead.co.uk/fitting-guides.htm

My limited understanding is that expansion and contraction in leadwork must be accounted for to avoid it splitting. This usually means limiting the size of individual pieces and overlapping them to allow for movement.

 

[AMc]

Can't answer your question about stitching, but I had a similar arrangement on my vinery which had my roofer scratching his head for a bit working out how to overlap the lead to make the run off smooth.
If it were me (again) I would ask about adding some sort of former (wood/brick/tile) under the lead in the corner that helps to avoid a build up of debris and moss in the corner where the wall is at 90 degrees to the slope.

 

[stuart45]

He probably means lead welding. That wall creates a similar situation to a chimney stack which has a welded back gutter as shown here.
htt://www.justlead.co.uk/back-gutter/vmchk.html
Peter Scoley is really helpful if you have a problem with leadwork.
AMc has a good point about potential problems in the corner. The Americans use a similar idea on stacks called a cricket, which helps stop the build up of leaves and snow.

 

[another_richard]

Just for info your link needs a p

http://www.justlead.co.uk/back-gutter/vmchk.html

 

[stuart45]

Thanks another_richard, the P on my key sticks a bit and needs a double ush sometimes.