Flashing is installed to surround roof features such as vents chimneys and skylights.
Fitting roof window flashing.
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.
Finally fit the flashing above the frame.
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.
Then move up the sides of the frame.
All the same rules of flashing apply except only the measurements of chase depth and drop are required.
This is a video showing the fitting of a velux roof window with instructions.
Start by fitting the sill flashing at the bottom of the frame.
Moving up on to the roof fit the flashing around the frame according to the manufacturer s instructions.