Stchimney Roof Counter Flashing

Flashing refers to the metal barrier installed where the roof meets any vertical wall including chimneys and dormers.

Stchimney roof counter flashing. Flashing directs rainwater away from these junctions preventing subsequent leaks and water damage. In good quality work the top is bent and set 1 to 11 2 inches into a mortar joint reglet. Step 1 cut the mortar joint. Cap flashings should be fastened to the chimney only.

Properly flashing a chimney is important to prevent water from leaking between the chimney and roof and getting into the building s walls. It involves two pieces of flashing. The first base flashing sits around the bottom of the chimney. Bend a piece of cap flashing to fit around the top corner of the chimney and add the cap flashing across the back of the chimney.

The counter flashing extends from the layer of bricks and then bends down overlaying the top edges of the primary step flashing. It directs water away from the chimney and seals off the gap between the pipe and the roof. Cut the side cap flashing to fit the angle of the roof so it overlaps each lower cap flashing at least 2 in. Pound the flashing into the grooves and fasten with the drive in expanding anchors.

Counter flashing counter flashing is placed over the step flashing parallel to the chimney. A piece of metal that is sealed to the chimney surface and covering the top of the step flashing to form a water tight barrier by directing water over and away from the step flashing. Counter flashing provides an added measure of protection. The second piece the counter flashing is embedded into the masonry of the chimney.

Not only will it prevent leaks but it will also extend the life of your chimney s masonry. The counter flashing is either cut into the brick face or embedded into the mortar between brick layers. Counter flashing is often used to flash chimneys. Water sheds from off the brick chimney surfaces down over the outside edge of the step flashing.

If the systems are a masonry chimney the counter flashing should be ground into the system to ensure that the majority of the water cannot bypass the seam of the counter and step flashing. There are different types of flashing for different chimneys but we ll focus on flashing designed for round metal pipe. The installation of counter flashing against a chimney works together with the base and step flashing to form a waterproof system for your roof. Bottom the bottom cap flashing or counter flashing is a single piece of metal that covers the vertical portion of the base flashing.

Three types of flashing are typically used on each roof.