All buildings have doors, windows, and mechanical equipment entering through walls and roof openings, and all of these are designed to keep water from infiltrating the interior of the building. One thing, however, that most people don’t even consider a vital part of the building, is the roof flashing.
A well-constructed, flat roof, complete with a drainage system, is the first line of defense when it comes to protecting the interior of the building from water. However, without flashing, the roof is no better than a roof with an uncovered opening. Here in the GTA we do get some heavy rains and snow so having a flat roof installed with quality flashings is just as important as the roofing materials itself.
Flashing is often overlooked or minimized in some installations. This is usually done by low-quality, unscrupulous roofing companies out to make a quick buck. However, if you hire a quality roofing company, they will take just as much care installing the flashing as they will the main roofing materials.
What is Flashing?
Flashing is a construction detail designed to protect joints in the flat and sloped roof where it meets with roof mounted structures and equipment such as parapet walls, mechanical devices entering through the roof, skylights, chimneys, hatches, vents or pipes to name a few. These items create gaps where water can infiltrate and expand and contract with temperature variations. Here in the GTA roof flashing protects the roof from excessive heat from the long summers and snow and rain from the harsh winters.
How Flashing Works
Flashing is installed where there is an intersection between the roof and a structure. It is usually made from a corrosion-resistant material such as galvanized metal and overlaps the roof and the structure, forming a valley which can lead water away from the opening it protects. It is sealed with a specialized roof sealant which expands and contracts with the changing weather.
Base flashing is installed to the roof itself and is covered by at least six inches of roof material. The other half of the flashing extends up the protrusion forming a valley to lead water away from the structure.
A quality installation of roof flashing includes the use of rubber gaskets around pipes and rounded structures that protrude from the roof. This is expensive but adds to the integrity of the water tight seal.
Valleys
Valleys are areas of roof where two or more sections of a roof meet at an angle. These are common with sloped roof installations. The valley has to have proper flashing installed to keep water from seeping under the roofing materials.
Flashing Repair
The failure of flashing is the leading cause for leaks in a roof. Flashing needs to be carefully inspected on a yearly basis to assure it is sound and free from cracks that could allow water to infiltrate the interior. Avoid the commonly sold roofing “goop” sold at hardware stores for repairs. It is often used by building owners but is only a temporary fix compared to the quality materials a licensed roofing contractor such as we find here in the GTA have.
Conclusion
A roof is a vital part of any building and should never be overlooked. The material the roof is made from is just as important as the flashing that seals it. Take the time to call your local roofing specialist to arrange an annual roof inspection that includes roof flashing. A little bit of prevention can save you a lot of money in the long-term.