By Daniel Watkins, Noble Chimney Sweepers.
When a chimney leaks and the flashing turns out to be intact, the answer is usually sitting on the roof behind the chimney, or rather it is missing from behind the chimney. It is called a cricket, sometimes a chimney saddle, and on a wide chimney it is not an upgrade or a nice-to-have. Plenty of houses in Frankfort have a chimney wide enough to need one and do not have one, and the damage shows up years later as a stain on a ceiling or a crumbling shoulder of brick.
What a cricket is and what it does
A cricket is a small peaked structure built onto the roof deck on the up-slope side of the chimney, the side facing uphill toward the ridge. It looks like a miniature gable roof wedged against the back of the chimney, with its own ridge running out from the masonry and two sloped faces shedding to either side.
Its job is simple. Without it, the back wall of the chimney sits square across the flow of everything coming down the roof, and the roof plane dead-ends into masonry. Rain, snowmelt, ice, leaves, and pine needles all pile against that wall. A cricket splits that flow and sends it around the chimney on both sides instead of into the joint.
When one is required
The common threshold is chimney width measured across the slope: a chimney more than 30 inches wide on a sloped roof gets a cricket. Below that, correctly installed step and counter flashing is generally enough to handle what reaches the joint. Above it, the area collecting water behind the chimney is large enough that flashing alone is being asked to do something it was never designed to do.
Two things push the requirement harder. A shallower roof pitch moves water slower and holds debris longer, so the pile behind the chimney sits wet. And a chimney positioned partway down a long slope collects everything shedding off the roof above it, which is a much larger volume than one near the ridge.
What happens when it is missing
The failure is gradual, which is why it goes unaddressed for so long.
Standing water and a debris dam
Leaves and needles collect in the dead corner behind the chimney and hold moisture against the shingles and the flashing long after the roof has dried. That constant wetting is what breaks down the sealant at the counter flashing and rots the roof deck underneath.
Ice, which is the real damage in our winters
Snow banks up against the back of the chimney and melts and refreezes there through every thaw cycle. Ice works its way under shingles and behind flashing, lifts them, and opens a path that stays open after the ice is gone. The next rain finds it. Freeze-thaw against saturated masonry also spalls the brick face on that back wall specifically, which is why the back of an uncricketed chimney so often looks worse than the other three sides.
Leaks that get blamed on the wrong thing
Water gets in behind the chimney, travels down the framing, and appears on a ceiling several feet away from the chimney. It gets diagnosed as a roof problem, the shingles get patched, and it comes back next spring because nothing changed at the source. If your chimney has leaked more than once after repairs, look at whether there is a cricket back there at all.
How it should be built
A cricket is framed and sheathed like a small roof, then covered, and it needs its own flashing where it meets the chimney and where it ties into the main roof plane. On a narrower chimney it can be formed from a single soldered metal saddle. On a wider one it is framed lumber, sheathed, and covered in metal or roofing matched to the roof.
The part that gets skipped is the flashing at the joint. A cricket built and then simply sealed against the brick with caulk will leak, because caulk is not a flashing detail and it will not survive the movement between wood framing and masonry. It needs proper counter flashing let into a mortar joint, exactly as the sides of the chimney do. If you want the full picture of how a chimney is supposed to be sealed to a roof, our chimney repair page covers the flashing work in detail.
This is roofing work as much as chimney work, and the honest position is that it usually involves a roofer, because it means opening the roof deck. What we can do is tell you whether the cricket is the actual problem, whether the flashing and counter flashing are correct, and what condition the masonry on that back wall is in after however many winters it has been sitting wet. That last part often matters more than the leak itself, and it is covered under our chimney inspection.
How to check your own
From the ground with binoculars, look at the up-slope side of the chimney and see whether there is a small peak coming off the back of it or whether the roof runs flat into brick. If you can safely see the back of the chimney from an upstairs window, look for a dark stain line, matted leaves, or moss along the joint. Inside, check the attic on the chimney side for water staining on the sheathing or on the framing beside the chase. Our DIY maintenance guide has the rest of the seasonal checks worth doing before the burning season.
Noble Chimney Sweepers is certified, bonded and insured, owner-operated, and I have 14 years in this trade. If you have a chimney that keeps leaking and nobody has been able to explain it, call and we will take a look at what is actually happening on that back wall, with the price given up front before any work. We are at (708) 432-5747, seven days a week, 7 AM to 7 PM.
Frequently asked questions
How do I know how wide my chimney is for this purpose?
The measurement that matters is the width across the roof slope, meaning the dimension of the chimney that runs horizontally along the ridge direction, not the depth up and down the slope. Anything past roughly 30 inches across is in cricket territory on a sloped roof.
Does a chimney at the ridge need a cricket?
Usually not. A chimney that comes through at or very near the peak has almost no roof above it, so there is no volume of water and snow shedding down onto its back wall. The requirement is driven by what is uphill of the chimney.
Can I just add more sealant behind the chimney instead?
No, and this is the most common attempted shortcut. Sealant fails at the seam between masonry and roofing because the two move differently through temperature swings, and it does nothing about debris and ice piling up. It buys a season at best.
Is a cricket the same as a saddle?
Yes, the terms are used for the same thing. You may hear either one from a roofer or an inspector. Some people reserve saddle for a one-piece metal version on a narrower chimney and cricket for a framed one, but the function is identical.
Will a home inspector flag a missing cricket?
A thorough one will, particularly on a wide chimney on a low-pitch roof, and it commonly comes up during a sale. Whether it becomes a negotiating item depends on whether there is already visible water damage, which is why it is worth knowing before you list.
My chimney is only about two feet wide. Am I fine?
Probably, from a code standpoint. Still check the joint behind it, because a narrow chimney on a shallow roof with trees overhead can collect enough debris to hold water against the flashing. The width rule is a threshold, not a guarantee.
Should the cricket be replaced when the roof is redone?
Yes, and that is the right time to deal with all of it. The flashing, counter flashing, and cricket should be renewed with the roof rather than reused, and if the chimney needs any masonry work on that back wall it is far cheaper while the roofer is already there.
Does a missing cricket affect the inside of the chimney?
It can. Water entering behind the chimney travels down through the masonry and reaches the flue and the smoke chamber, where it accelerates mortar deterioration and rusts the damper. A chimney that has been taking water for years often has interior problems that a homeowner assumed were unrelated to the roof.
Published September 24, 2026