Roof Flashing – An Important Aspect of Roofing!
It is commonly recognized that everyone needs a roof over their heads! This part of a building structure essentially keeps out any undesirable indoor elements such as rain, snow or even sunshine. Through the use of flashing on the top of a building, seepage of water through vulnerable places in that area such as joints is prevented. Therefore, it is best to make sure that flashing is properly used and installed from the very beginning of a building’s construction so that there is no necessity for it to be redone at a later stage after internal damage has occurred.
The material used for flashing is a sheet of metal, usually aluminum or galvanized steel. The metal material is placed over joints on the roof to prevent the seepage of water. Although this sounds simple, it is based on sound engineering principles and has been known to builders for a long time. It works on the simple principle that for water to penetrate a roof, it must work itself upwards against gravity and follow an unnatural course during which a driving force, such as wind, is dissipated. Gravity is used to direct water over the material on the top of a building and prevent that liquid from seeping through the joints to underlying areas.
There are two types of flashing: concealed or exposed. Any material used must be durable, weather resistant, low maintenance and be able to handle normal roof expansion and contraction under different weather conditions. The materials commonly used for exposed roof flashing are: aluminum, copper, painted galvanized sheet, stainless steel, lead, and zinc alloys to name a few. Most of these materials have a working life of 20 to 30 years; however, lead sheets which are infrequently used due to environmental concerns, have two advantages including it is recyclable and has a working life of up to 500 years. Concealed materials commonly used are: sheet metal, bituminous fabric, and plastic sheeting to name a few.
Common flashing locations that are used in building construction include:
- Roof – Placement is wherever there is a discontinuity or protrusion that would prevent the smooth flow of water. It is generally used around pipes, chimneys and other such protrusions; it deflects water away from such types of joints.
- Walls – Flashing may be used in walls to prevent entry of water into a wall and is generally done on interruptions such as windows or beams.
- Windows – Sill flashing is concealed and is done to prevent the ingress of water through window sills and thresholds.
- Roof and Wall – Base flashing is done at the base of walls and incorporate weep holes to permit water to escape. It is usually done where the roof and wall meet.
It is essential that roof flashing be done in a professional manner by a Conroe roofing expert who understands the weak points of a roof. When properly done, one of the biggest problems that can occur after building construction has been completed, namely water seepage, can be kept at bay for a long period of time!