Is your chimney leaking? Do you constantly caulk and tar your chimney flashing to keep it from leaking?
When it comes to the chimney, most problems occur when the flashings are too small or are not installed properly, if at all. There are four critical areas that are required when flashing a chimney.
- Step Flashing
- Counter Flashing
- Apron Flashing
- Chimney Cricket
Solutions: Flashings must have minimum sizes and must be installed properly to seal the joints between your chimney and your roof surface as shown below.
Figure above - Common Metal Roof Flashings
Step flashing is a metal flashing used at the intersection of the sidewall of your house or chimney and a sloping roof; the flashing is installed individually under each shingle going up the side of the wall or chimney until it reaches the top. The resulting appearance resembles a flight of steps - thus the term step flashing.
Couterflashing on chimneys and other brick veneer walls is one of the most common items that is not installed. The primary reason is that the counterflashing needs to be installed over the step flashing. Counterflashing must be mounted properly and in the correct positions. The brick needs to be scored with a grinder and the flashing then needs to be installed. Many roofing crews, or homeowners installing their own shingles, are reluctant to cut into a brick chimney or lack the knowledge. The result is that caulking or tar is used in place of counter flashing and leaks occur down the road.
Figure above - Masonry Mortar Joint With Inset Metal Counterflashing
Figure above - Masonry Mortar Joint With Continous Counterflashing or Riglet Flashing
The apron flashing is the flashing that covers the joint between a vertical surface and a sloping roof, as at the lower edge of a chimney.
A cricket is constructed to divert water from a horizontal intersection of a roof and chimney. Crickets typically are constructed from metal. The metal type and thickness used for cricket flashings should be commensurate with the anticipated service life of the asphalt shingle roof system. NRCA suggests cricket flashings for an asphalt shingle roof system be fabricated from one of the following metal types and thicknesses:
• 26-gauge galvanized steel/
prefinished galvanized steel
• 0.032-inch aluminum/prefinished
• 26-gauge stainless steel
Cricket flashing also requires some form of counterflashing to cover and protect the top edges from water infiltration.
For a free roof evaluation of your shingles, flashing or hail damage inspection, contact Timberland Exteriors and we will send one of our roofing specialists out to meet with you at no charge.