Flashing just like most other materials asphalt flat roofs tend to expand and contract with changing weather and temperatures.
Flat roof leaking at flashing.
If you can aim for 150mm.
The minimum standard is 50mm.
This video demonstrates where flashing could be leaking from on a brick wall.
Metal flashing copper bend at a 90 degree angle making the transition between the roof and chimney.
Metal flashing that runs alongside a wall loosens up or the caulking gives and a major leak starts.
It is the first place to troubleshoot for leaks on a roof.
On a shingle roof the flashing will get clogged with debris and in turn the water will get diverted under the shingles where it could start leaking.
Flashing is the number one cause of leaks on flat roofs.
This flashing rests on the front edge of the lowest batten with a squash fold to direct any possible.
Just make sure you leave enough room for gutter maintenance.
The best way to.
Flashing on a wall above a flat roof.
The other issue is if the installer nailed the shingles through the flashing then those nails could start rusting and cause a skylight to leak.