Complex Roof Problem
This roof leaks during the snowy part of winter and during storms in the summer, certainly due to poor flashing.
The soffit that meets the roof is one of the
toughest areas to waterproof. In the
photo, you can still see signs of an ice
dam. An ice dam occurs when snow
melts and the water freezes when it hits
the colder edges of your roof. Eventually,
water pools behind the dam and works
its way back up under the shingles and
under the soffit until it finds an opening
through the roof.
The solution begins with good flashing, since this
should stop leaks from rainfall and
might stop the leaks from ice dams as
well. Begin by removing the shingles
down to the wood sheathing and slip a
strip of adhesive ice-and-water barrier
(available where roofing products are
sold) under the soffit/main roof joint.
Depending on how the roofs join, you
may have to cut a slot to work it in far
enough. It should overlap another piece of
ice-and-water barrier laid below, all the
way down to the roof edge. This should
cover the most leak-prone areas. Then
reshingle, sliding metal step flashing
behind the fascia board (the trim behind
the gutter). The valley flashing,
laid over the joint where the two roofs
meet, should overlap the step flashing at
least 2 in.
If leaks continue to occur from ice
dams, consider installing roof edge heating
cables. (Find them locally at hardware
stores or home centers.)
Improved attic insulation and ventilation
are usually the best ways to prevent ice
dams, but they might not be effective in
this complicated roof situation.