Roof Crickets: The Little Roof That Saves the Chimney
Behind every wide chimney on a well-built roof sits a cricket, a small diverter peak that splits the water a chimney would otherwise dam. The most consequential roofing detail most homeowners have never heard of.
What a cricket is
A cricket (or saddle) is a small peaked structure built on the up-slope side of a chimney, ridge running perpendicular to the main slope, so water flowing down the roof splits and passes around the chimney instead of slamming into its flat back and pooling there. It is a miniature gable whose entire job is diversion: framed in wood, sheathed, membraned and flashed as part of the roof, or on smaller chimneys, fabricated entirely from metal. Codes require one behind chimneys wider than 30 inches measured across the slope, and good roofers build them behind narrower ones in snow country and heavy-rain regions anyway, the little roof the big roof depends on, and a first cousin of the valleys it creates on each side.
Why chimneys need them
A chimney is a dam: the widest flat obstacle on most roofs, standing perpendicular to the flow. Without a cricket, everything the slope above delivers piles against the back wall of the chimney, ponding against the back flashing, soaking mortar joints, freezing into miniature ice dams each winter, and collecting the leaves and needles that hold moisture year-round, the exact recipe for the chronic chimney leak that resists repair after repair because the repairs address flashing while the problem is hydraulics. The cricket ends the dam: water arrives at a peak, splits, and exits down the two small valleys at speed. It is drainage engineering at the scale of a doghouse, and it works for the life of the roof.
How crickets are built
A proper cricket is roofing in miniature and gets the full stack: framing pitched at least as steep as the main roof (steeper sheds better), sheathing, ice-and-water membrane across the whole assembly and up the chimney (this is a valley-and-penetration zone, the membrane earns its keep), metal or matching-shingle surfacing, its two valleys detailed per valley rules, and flashing tied into both the chimney (step and counter-flashing let into mortar joints) and the main field. Metal crickets, soldered or seamed from copper or painted steel, serve smaller chimneys elegantly. The build happens naturally during re-roofing, which is when missing crickets should always be added: the framing hour costs little with the field open and everything after it is leak prevention on autopilot.
The missing-cricket leak
The signature: a chimney that leaks “sometimes”, heavy rains, snow melt, spring thaw, with stains appearing at the chimney breast indoors, repairs that hold a season then weep again, granule loss and debris piles visible behind the chimney, and mortar spalling on the roof-facing side. Each repair treats flashing; the water keeps arriving faster than any flashing can shrug. The diagnostic is one glance from the ground or the inspection ladder: a wide chimney with a flat back and no peak behind it is the answer looking at you. The fix ranks among roofing best values, framed and flashed behind most chimneys in a day, permanent by design, and cheapest of all when bundled into the re-roof that was coming anyway. We build and retrofit crickets across our service areas, and check for their absence on every chimney we inspect.
Roof cricket FAQs
What is a cricket on a roof?
A small peaked diverter, a saddle, built on the up-slope side of a chimney, its ridge perpendicular to the main slope, splitting descending water around the chimney instead of letting it dam against the flat back. Framed and flashed like a miniature roof (or fabricated from metal on smaller chimneys), it is the standard cure for chronic chimney-back leaks.
When does code require a roof cricket?
Behind chimneys wider than 30 inches measured across the slope, per model building codes, with good practice adding them behind narrower chimneys in snow and heavy-rain country. Wide chimneys without crickets are among the most common code-and-leak findings at inspection and the easiest permanent fix to bundle into a re-roof.
Why does my chimney leak even after new flashing?
Very possibly hydraulics, not flashing: without a cricket, the slope above delivers water faster than any back flashing can shed it, ponding, freezing and debris-damming against the chimney each season. The tell is intermittent leaking during heavy rain and melt, repairs that hold briefly, and a flat chimney back with no diverter, flashing treats the symptom; the cricket removes the cause.
How much does adding a cricket cost?
Modest as roofing goes, a day of framing, membrane, surfacing and flashing behind most chimneys, and least of all when added during re-roofing with the field already open, which is when every missing cricket should be corrected. Against the chronic leak cycle it ends (and the masonry damage ponding causes), it ranks among the best values in roof work.
Chimney leaking on repeat?
One look tells us whether flashing or hydraulics is the culprit, and a cricket ends the argument permanently. Get a free assessment.
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