What is Roof Flashing?

5/9/2015

Roof Flashing- Getting Started

Intruders come in different forms. They may be burglars, wildlife straying onto your property, or even the elements. Homeowners recognize the importance of roofing past its alluring aesthetics – that it is crucial to the fidelity of a home by protecting it from the intruding elements. Without a form of protection for the important areas of the roof that it will not effectively keep the elements at bay. The harmful effects of this possibility are significant, which is why a roof system is not truly complete until all areas of the roof are adequately covered – and roof flashing is key in this respect.

Wherever two surfaces meet in a building structure you will find an opening, penetration or seam, and the installation of flashing is needed in these areas for proper protection.

The Asphalt Roofing Manufacturers Association, defines flashing as: Pieces of metal or roll roofing membrane used to prevent seepage of water into a building around any intersection or projection in a roof, such as vent pipes, chimneys, adjoining walls, dormers and valleys.

The term flashing, however, is also used to describe the process of applying these protective materials – what’s more is that there are other materials beyond metal which are used to ‘flash’ a roof area.

Roof Flashing: Why is it important?

Flashing is applied on roofs for the purpose of permitting the safe flow of water over areas where there is a higher chance of water infiltrating into a home. These areas include, but are not limited to, valleys (the internal angle formed by the meeting of two sloping roof planes), ridges (the uppermost ‘peak’ where two sloping roof planes meet), chimney walls, skylights, and dormers. At these locations there is increased vulnerability because the water channels through the ‘path of least resistance’. This means that special protection is needed in these areas to prevent water from infiltrating the roof, damaging the interior of the home, and possibly leading to indoor mold problems.

Roof Flashing: Why is it effective?

Roof flashing materials must be chosen carefully, as they are subject to stress – such as expansion and contraction of the roof deck or building, and wind pressure. To function efficiently, flashing materials should have the following qualities:

1. Durability—Roofing materials are designed to last for many years. To match the longevity of these materials, flashing has to be just as durable.
2. Weather resistant—Long-term exposure to water and wind has varying degrees of effect on flashing materials, so they  are required to have  resistance against the elements.
3. Permit movement—Seasonal changes and weather patterns affect roofing materials in alternate ways (varying degrees of contraction and expansion). For this reason flashing materials are required to be adaptable to the changes of the prevailing weather condition.

If you have any questions about the flashing on your home, call a roofer to have it inspected.