White Plains Roofing: Article About Roof Penetrations
During installation, roofing materials must be cut in order to make room for chimneys, HVAC equipment, and other necessary protrusions. These areas become vulnerable to leaks and structural damage over time. In order to seal the penetrations, roofers must place flashing in the appropriate spots and then advise the property owner to keep it in good repair. White Plains roofing specialists use three basic methods to ensure that these potentially hazardous roof sections are watertight. Whether the technician uses a counter flashing, the caulking and banding process, or a pitch pocket, the roof stays dry for a reasonable period of time.
The most common approach involves laying a counter flashing over the edges of the base flashing. It is a cap shaped device that extends down at least two inches past the rim and directs water away from the area of penetration. The cap is attached to the base flashing through its side legs with screws and neoprene washers. This method of waterproofing is particularly effective when installing skylights. Sometimes the counter flashing is attached through the top, but special sealing bolts and a careful design are required for satisfactory results. The washer must not be permitted to compress too much or become exposed to sunlight.
In the case of a round penetration such as a tube or pipe, caulk and band waterproofing does the job.
A Roofing professional from Precision Roofing of White Plains NY can answer your questions about commercial roofing or shingle replacement.
Since base flashing rarely reaches higher than eight inches, this method is very practical for unusually tall penetrations. The top of the base flashing is tightly secured with a draw band before caulking is applied above it. Then a storm collar goes over the caulking for the sake of protection from the elements. The drawbacks to the caulk and band method are that it works only for rounded objects and needs routine maintenance after installation.
For difficult projects, roofers often resort to pitch pocket sealants. A piece of sheet metal is formed into the shape of a flanged sleeve that is used to create a dam in the roof. A sealant is then poured into the pocket where it flows around the penetrating apparatuses. While the pitch pocket method is effective, it is chosen mostly for oddly shaped protrusions and clusters of items situated inside the same hole in the roofing materials. It is named for the original sealant material employed during the process; modern technicians have replaced coal tar pitch with chemical sealants and grout fillers. Like a caulk and band application, a pitch pocket system requires maintenance. Unless a cover shades it from UV rays and weather, the sealant will harden and crack often.