Put horizontal flashing across the bottom of a front dormer wall.
How to flash a roof dormer.
One common method is to lay the edge metal under the eaves membrane and over the rake details concrete masonry roofing wrb flashing.
In this article veteran remodeler mike guertin shows how to flash a dormer with bombproof details.
When installing trim provide sufficient clearance as shown or use a moisture tolerant material such as pvc or boral.
Shed dormers require a continuous strip of flashing along the top of the lower roof plane where it meets the steeper roof plane.
Coat the flashing with a zinc based primer followed by two or more coats of spray on rust preventive metal paint.
If you do not wish to form your own corner flashing you can buy pre bent pieces and cut them to size or use a piece of corrugated aluminum which is easier to bend.
1 install roof underlayment up to the dormer cutting it a few inches short of the roof wall joints at the front and side walls.
You may want to paint the flashing to match the roof.
While the gold standard for roof flashing is soldered copper the fact is that for economic reasons the vast majority of roof flashing is done with aluminum.
First use a stiff wire brush and solvent to clean the surface of any dirt debris or corrosion keep solvent away from asphalt shingles.
Two ways to flash roof edges protect the eave from ice dams and sideways rain step one in steep slope roofing is the edge flashing.
Roof shingle over step flashing.
Apply peel and stick membrane to the front wall of the dormer making sure it overlaps the roof underlayment and wraps up onto the wall 6 or 8 inches.
Bend the corner flashing tightly around the corner.
Step flashing on roof peak.
Tim healey to protect this vulnerable juncture from water intrusion and rot install solid blocking at the eaves to provide a substrate for peel and stick flashing then install the flashing shingle fashion to protect against water ice and snow.
Here s a step by step look at how to flash a dormer so that water is carried away from those vulnerable areas.
A critical juncture that often fails is where these two flashings meet.
