Finishing lead in roof

[North]

Hi all,



My builders left the extension roof lead flashing unfinished as per the pictures.

I have the bit of lead and the resin ready to patch the missing bit. However and before doing that I would kindly request any advice that any of you may have on how to do a nice finishing.

Thanks in advance

 

[vinn]

Does the flat roof actually have a fall away from the wall sloping down to a gutter?
The problem is that the flashing and flat roof cap sheet at the abutment appear to be wrong.
Does the cap sheet stop dead at the bitumen or has it been carried up the brickwork by about 50mm behind the bitumen?
There should be an angle fillet at the abutment.

Lengths of lead sheet cover flashing should be 1500mm to 1600mm max. (including overlaps of 150mm).
If the abutment detail had been correct your flashing should have been chased into the next higher course above.
The old render has never "taken" (stuck) to the brickwork and needs removing and re-doing with a BellCast just above the flashing.
On the average flat roof, single lengths of cap sheet should be used from edging to edging - not pieced-in with a butt joint such as you have.
The lead has been sealed with two kinds (brown & grey) of caulk, and the sealant has not been tooled smooth into the chase.

 

[DodgySailor]

Hi thanks for response.
The roof has got a small angle down to a gutter. The cap sheet is around 2cm above the bitumen. I guess the next step above would have been too high?
Can you clarify what do you mean with the angle fillet at the abutment?
The gap is around 20cm, the plan is to cut a piece of lead 20 cm +15 cm each side for overlapping, wedge it down and seal it.
Where should the render stop exactly? Just before the seal?
Thanks

 

[vinn]

Best practice says that the cover flashings should be chased in 150mm above any deck.
The BellCast is fixed immediately above the chased in bed ie approx 155mm to 160mm above the deck.
The angle fillet (AKA a Cant Strip) can be googled.
If the cap sheet turns up the abutment at 90 degrees without the benefit of an angle fillet then it might possibly crack at that inside corner.
Your proposed lead flashing patch-in is fine.

 

[North]

Hi last question, i fitted the missing bit but i realized that they did an extremely rubish job. The lead has not been fitted properly into the groove and it comes off very easyly so I will need to replace everything.
My question would be is it better to use wider lead like the one I used in the middle so that it prolongs along the flat roof?the one fitted just hangs from the groove and it bearly reaches the top surface of the roof.

 

[vinn]

Without your answering the questions I asked you I cant advise you clearly.
google "flashing at abutments images" to get a pictured idea of what you should have.
You dont need lead flapping down the roof as in your missing piece.

 

[North]

This picture depicts exactly what I have at the moment. Does it help? My plan is to remove all the flashing (at the moment there are two long bits of around 3mt on each side or my repair) Cut them off into 1.5 mt each and make the overlapping as you suggest above. I will have to buy an extra lead roll. I assume I will be safe by following the picture?
Thanks

 

[vinn]

You will be safe by following the picture.

 

[North]

Thanks a lot, i shall leave you in peace for a while.