Some chimney leaks are a flashing problem. Others are a geometry problem, and no amount of flashing work will fix them. When a wide chimney sits on a sloped roof with nothing behind it, every drop of water coming down that slope arrives at a masonry wall and has nowhere to go.
The part that solves this is a chimney cricket — a small peaked roof built behind the chimney that splits the flow and routes it around both sides. On the roofs where it is needed and missing, it is the single most common reason a chimney keeps leaking after two or three attempted repairs.
This article is about the cricket itself. For how the flashing around a chimney is supposed to be built, start with our guide to chimney flashing leaks.
What a Cricket Actually Is
A cricket, also called a saddle, is a miniature ridge running from the back of the chimney up the slope. It has two small planes that meet at a peak, turning the flat uphill face of the chimney into a wedge that parts water the way a ship's bow does.
Small crickets on narrow chimneys are sometimes formed in metal, but on a wide chimney the cricket is real structure — framed, sheathed, membraned, flashed, and shingled like any other part of the roof.
Why the Uphill Side of a Chimney Is a Trap
Without a cricket, the back of the chimney is a dam. Water running down that whole section of slope hits the masonry, spreads sideways, and has to find its way around the corners. Three things happen there, and all of them cause problems.
Water sits. Standing water on the uphill side works against the shingle laps and the flashing seal in a way running water never does.
Debris collects. Leaves, twigs, and grit wash down the slope and pile against the chimney, holding moisture on the roof surface indefinitely and accelerating shingle wear.
Snow and ice linger. North Texas does not see much of it, but a freeze that follows a wet system leaves ice packed behind the chimney long after the rest of the roof has cleared, and meltwater backs up under the shingle courses.
The wider the chimney, the more water arrives at that face, and the more the flashing is asked to do a job it was never designed to do alone.
Signs Your Chimney Is Missing One
- Water stains appearing on the ceiling near the chimney chase, especially on the uphill side.
- A dark, permanently damp band of shingles across the back of the chimney.
- Debris piled behind the masonry every time you look.
- Deteriorated or repeatedly recaulked flashing on the uphill face only, while the sides look fine.
- Rot in the decking behind the chimney, discovered during a repair.
That last one is why we treat this seriously. Water held against the back of a chimney soaks the sheathing beneath it, and by the time the leak reaches a ceiling, the plywood is often soft.
How a Cricket Is Built
The construction sequence matters more than the materials.
- Framing. Two sloped planes are framed off the roof deck and the back of the chimney, meeting at a centered ridge that runs up the slope.
- Sheathing. The planes are decked so they carry a load and hold fasteners.
- Membrane. Self-adhering ice-and-water shield covers the cricket and laps well onto the surrounding deck, because the low corners where the cricket meets the roof are effectively small valleys and need the same protection our guide to valley leaks describes.
- Flashing. Step flashing up each side of the cricket, apron flashing where the cricket meets the chimney, and counterflashing cut into the mortar joints and sealed so nothing relies on surface caulk.
- Shingles. Woven into the surrounding courses so water runs across the laps, never into them.
Done correctly, the finished cricket looks like it was always part of the house — which is the point.
Retrofitting a Cricket on an Existing Roof
Adding a cricket to a roof that never had one is normal work. A roofer opens the shingle courses above and beside the chimney, removes the old flashing, builds the cricket, and reweaves the shingles into the existing field. On a sound roof this is usually a single day.
Two practical notes. The shingles woven back in must be flexible enough to lift without cracking, so on a roof near the end of its life a retrofit is better folded into a full roof replacement, where the cricket costs far less as part of the larger job. And expect the decking behind the chimney to need attention; after years of damming water, it usually does.
If your roof has plenty of life left and the chimney is the only trouble spot, a targeted roof repair that builds the cricket properly ends the problem — instead of resealing the same joint every couple of years and hoping.
Frequently Asked Questions
What is a chimney cricket? A cricket, sometimes called a saddle, is a small peaked structure built on the uphill side of a chimney. It splits the water coming down the slope and sends it around both sides instead of letting it pile up against the masonry.
Does every chimney need a cricket? No. Narrow chimneys shed water around themselves without help. Crickets become important as the uphill face gets wider, and on steeper slopes where runoff arrives with more force. Wide chimneys without one are a common source of chronic leaks.
Can a cricket be added to an existing roof? Yes. A roofer opens the shingles above the chimney, frames and sheathes the cricket, adds membrane and flashing, and weaves the shingles back in. It is usually a one-day job and is most economical done during a roof replacement.
Chimney that keeps leaking no matter what? Call Cannon Roofing at (940) 627-1045 or request a free quote. We build crickets and reflash chimneys properly across Decatur, Wise County & Greater North Texas.