Roof leaks happen most often around chimneys, either caused by inadequate flashing or insufficient caulk. The chimney itself might be cracked or otherwise damaged.
Any object that penetrates your roof, such as a vent pipe, can also be a source for leaks.
Look for roof leaks around:
- Vent pipes
- Damaged or poorly installed drip-edge
- Plumbing stacks
- Dormer walls
- Wall flashings
These are the most vulnerable areas of the roof and among the most neglected, because they require a great deal of time and expertise to maintain.
Roofs are designed to use gravity to shed water downward from the peak of the roof to the eaves’ edges. Shingles are meant to help this process.
However, if underlayment is not installed under the shingles, wind driven rains or melting snow trapped on the roof surface can back up under the shingles and leak into the wood sheathing and insulation. Eventually, this roof leak becomes visible in the drywall or plaster.
Did you know?
Many roofs have shingles installed directly onto the roof sheathing, because the Ontario building code only requires the installation of underlayment up to the eave’s edges.
If the roof was installed by a builder and not a roofing specialist, chances are it was installed only according to the very minimum requirements of the code. Today, many roofing contractors are still applying roofs with only minimal underlayment, thus exposing your roof to these types of leaks.