Stopping chimney leaks in Vancouver, WA with new flashing and crickets

Chimneys are one of the hardest spots on a roof to keep dry. A masonry chimney moves differently from the wood roof around it, so the flashing has to allow for that while still sealing out water. A proper chimney flashing system has several layers: step flashing woven with the shingles, counter-flashing set into the mortar joints and lapped over the step flashing, an apron at the front, and a back pan or cricket behind.

When any piece is missing or failing, water gets in. The usual culprits are counter-flashing that pulled out of the mortar, step flashing that rusted through, and no cricket on a wide chimney, so water and fir needles pile up behind it. We remove the old flashing, cut fresh reglets where needed, and install a complete new system matched to your chimney.

How a chimney flashing system works

Chimney flashing is built in layers that overlap so water always flows outward. Step flashing pieces are woven in with each course of shingles along the chimney sides and bent up against the brick. Counter-flashing is set into a groove, called a reglet, cut into a mortar joint, then folded down over the step flashing. The front apron covers the downhill face, and the back is handled with a pan or a cricket.

Because the chimney and the roof framing expand, contract and settle at different rates, the two layers are not fastened to each other. That small gap lets them move without tearing. When someone seals the gap with a thick bead of caulk or fastens the counter-flashing straight onto the step flashing, the system loses that movement. In a few seasons, cracks open, and the leak returns in the same spot.

What a cricket does and when you need one

A cricket, sometimes called a saddle, is a small peaked roof built on the uphill side of a chimney. It splits water and debris to either side instead of letting them dam up against the brick. Wide chimneys usually need one. Without it, water pools behind the chimney every storm and fir needles pack into the corner, holding moisture against the flashing for weeks. It is a small build with a big effect on leaks.

• Framed from lumber and sheathed to match the roof
• Covered with underlayment and metal or shingles
• Tied into the chimney with its own flashing
• Sheds water and needles to both sides
• Cuts down on pooling and rot behind the chimney

Reflashing a brick chimney step by step

We start by removing shingles around the chimney and pulling out the old flashing and any layers of sealant. We check the decking at the chimney base, since this is a common spot for rot. Then we cut new reglets into the mortar joints with a masonry saw, install new step flashing course by course, set counter-flashing pieces into the reglets, and seal them with a masonry-rated sealant. Each layer is checked before the next goes on.

If the chimney needs a cricket, we frame and sheathe it before the step and counter-flashing go on, then flash it into the brick. Finally, we reinstall shingles and check every lap. If we see loose bricks, crumbling mortar or a cracked crown on top, we point it out, since water entering through the masonry itself can look just like a flashing leak from inside the house. That way you are not chasing the same stain twice.

Framed chimneys and chase covers

Many newer Clark County homes have framed chimney chases with siding instead of brick, often around a gas fireplace or wood stove flue. These leak in different ways. Water can get in through the siding, around the step flashing, or through a rusted metal chase cover on top. We check all three. Reflashing a framed chase follows the same rules as roof-to-wall flashing, and a rusted chase cover is replaced with a new sloped one that sheds water.