When fitting flashings to flat roofs no overlap onto the roof is required as the roof itself will have it s own upstand flashing built into it.
Fitting roof window flashing.
Secure the flashing as instructed with nails or roof cement.
All the same rules of flashing apply except only the measurements of chase depth and drop are required.
Then move up the sides of the frame.
Read the instruction manual and check all the fixings and fittings are included as listed in the manual.
Http www fixmyroof co uk install roof flashings this video shows you the basics of installing lead roof flashings simple apron flashings or cover flashin.
Roof flashing is a thin material usually galvanized steel that professional roofers use to direct water away from critical areas of the roof wherever the roof plane meets a vertical surface like a wall or a dormer.
Flashing is installed to surround roof features such as vents chimneys and skylights.
Moving up on to the roof fit the flashing around the frame according to the manufacturer s instructions.
Start by fitting the sill flashing at the bottom of the frame.