By The Roofing Brief Team. Last reviewed: August 2026.
A roofing cricket is the small peaked ridge, also called a saddle, that a roofer builds on the high side of a chimney or other wide roof penetration so water splits and runs around it instead of ponding against the back wall. It is a permanent diverter framed into the roof, not a flashing accessory, and on chimneys wider than 30 inches it is required by code. This page explains what a roofing cricket is, every roof location that needs one, how to tell whether your roof already has a working cricket, and the terms crews use for it. For the full carpentry and cost breakdown, we link to our step-by-step build guides throughout.
What is a roofing cricket?
A roofing cricket is a ridged structure, shaped like a miniature gable roof, set on the up-slope side of a chimney, skylight, or curb to divert water around the obstruction. It rises from the main roof plane to a peak or ridge behind the penetration, so runoff and snowmelt split to both sides rather than collecting against a flat vertical face. The industry uses cricket and saddle for the same part.
The problem it solves is simple physics. Water flowing down a slope hits the back wall of a wide chimney, has nowhere to go, and pools. Standing water rots deck sheathing, degrades masonry mortar, and forces its way under flashing. A cricket gives that water two downhill paths off the corners of the chimney instead of one dead end.
Cricket vs saddle vs diverter: the terms untangled
Cricket and saddle mean the same thing, but crews use several nearby terms for related parts, and mixing them up leads to the wrong repair. A cricket or saddle is a framed water diverter behind a wide penetration. A diverter or kickout flashing is a small bent metal piece, not a framed structure. A valley and a curb are different parts entirely. The table sorts them out.
| Term | What it is | Where it goes | Framed or flashing |
|---|---|---|---|
| Cricket / saddle | Peaked mini-roof that splits water around an obstruction | Up-slope side of a chimney, skylight, or curb | Framed structure |
| Diverter (kickout) flashing | Bent metal that throws water away from a wall into the gutter | Where a roof edge meets a sidewall | Flashing piece |
| Valley | Channel where two roof planes meet and drain together | Internal angle between two slopes | Roof plane detail |
| Curb | Raised frame that lifts a skylight or unit above the roof | Around skylights and rooftop equipment | Framed base (often needs its own cricket) |
The key distinction: a cricket is built up as its own little roof, while a diverter is a single formed piece of metal. Our roof saddle install sequence covers the saddle wording in more depth, since some regions default to saddle over cricket.
Where a roof needs a cricket (it is not just chimneys)
Chimneys are the most common place for a cricket, but any wide obstruction that blocks downhill flow can need one. The rule of thumb: if a penetration is wide across the slope and sits below the ridge, water piles up behind it and a cricket belongs there. Skylights, HVAC curbs, dead valleys from additions, and wide walls all qualify depending on width and slope.
| Location | Why a cricket is needed | Typical trigger |
|---|---|---|
| Chimney | Wide masonry blocks runoff and holds water against the back wall | Width over 30 in across the slope (code) |
| Skylight | Frame dams water on the up-slope side, especially on low pitches | Wide units or low slope where water lingers |
| HVAC or equipment curb | Rooftop unit curb traps water and debris behind it | Common on low-slope commercial roofs |
| Dead valley (addition or dormer) | Two roofs meet and trap water with no clear outlet | Where a new roof ties into an existing wall |
| Wide wall or parapet | Long horizontal face collects sheeting water | Roof-to-wall runs on low-slope roofs |
On low-slope and flat roofs, crickets built from tapered insulation do the same job for drains and curbs, and they are usually pitched steeper than the main field so water clears. The principle carries across every roof type: no flat trap behind a wide obstacle.
When code requires a cricket: the 30-inch rule
The International Residential Code requires a cricket where a chimney measures more than 30 inches (762 mm) parallel to the ridgeline and does not intersect the ridge. That is the trigger in IRC Section R1003.20. Below 30 inches wide, or when the chimney straddles the ridge so water already splits, code does not force a cricket, though one can still help on low pitches.
The same section also requires that the intersection of the cricket and the chimney be flashed and counterflashed like a normal roof-to-chimney joint. In the 2024 IRC the requirement carries forward under the roof-assemblies chapter as Section R903.2.2, with the 30-inch threshold unchanged. Local amendments can differ, so confirm the adopted code edition with your jurisdiction. Our chimney flashing and counterflashing system guide shows how that joint is layered.
How big does a cricket have to be?
Cricket height is set by roof slope and chimney width, not guesswork. IRC Table R1003.20 gives the minimum cricket height (H) as a fraction of the chimney width parallel to the ridge (W). Steeper roofs need a taller cricket because water moves faster and needs a higher ridge to split cleanly; lower slopes need proportionally less height.
| Roof slope | Minimum cricket height (H) as a fraction of chimney width (W) |
|---|---|
| 12:12 | 1/2 of W |
| 8:12 | 1/3 of W |
| 6:12 | 1/4 of W |
| 4:12 | 1/6 of W |
| 3:12 | 1/8 of W |
To size a cricket from the table, follow these steps:
- Measure the chimney width parallel to the ridge. Call it W.
- If W is 30 inches or less and the chimney does not sit on the ridge, no cricket is required by code, though one may still be worthwhile on a low slope.
- If W is greater than 30 inches, a cricket is required under IRC R1003.20.
- Read the roof slope (for example 6:12).
- Multiply W by the fraction from Table R1003.20 to get the minimum cricket height H. A 40-inch-wide chimney on a 6:12 roof needs a cricket at least 1/4 of 40 inches, so 10 inches high.
Height is the code minimum, not a ceiling. Many roofers build slightly taller and wider than the table to move water further from the masonry. For the framing geometry behind these numbers, see our cricket sizing, slope, and framing sequence.
What a roofing cricket is made of
A steep-slope cricket is usually a small wood frame decked with plywood or OSB, wrapped in self-adhered membrane, then covered with metal flashing or the same shingles as the main roof. Small crickets on steep roofs tend to be metal-covered; larger ones use the field roofing material. The metal choices are aluminum, galvanized steel, or copper, in rising order of cost and lifespan.
- Frame: dimensional lumber or plywood ridge and hip pieces set behind the chimney.
- Deck: plywood or OSB sheathing over the frame.
- Underlayment: self-adhered ice-and-water membrane (the type meeting ASTM D1970) run up the chimney and over the cricket seams first.
- Surface: metal pan or field shingles, tied into step and counter flashing at the chimney.
Copper crickets last longest and are common on masonry chimneys and historic homes; aluminum is the budget default. Whatever the surface, the membrane goes down before the metal, because the membrane is the real waterproofing layer and the metal sheds the bulk of the flow.
How to tell if your roof already has a cricket
Most homeowners cannot say whether their chimney has a cricket, and a missing one is a slow leak waiting to happen. You can check from the ground, the attic, and after a rain without climbing on the roof. A working cricket reads as a small peaked ridge tucked against the up-slope face of the chimney.
- Stand back on the up-slope side of the chimney and look for a small triangular ridge rising off the roof against the back of the masonry.
- Look for a metal or shingled surface that splits to both sides rather than a flat gap packed with leaves.
- From the attic, check for short framing members behind the chimney and for water stains on the sheathing there.
- Inspect the ceiling and wall directly below the chimney chase for old or fresh staining.
- After heavy rain, watch whether water sheets straight into the back wall of the chimney or divides and runs off the corners.
If the back of the chimney is a flat shelf that collects debris, there is probably no cricket, and a wide chimney in that condition is a candidate for a retrofit during the next reroof.
Signs a cricket is missing or failing
A cricket problem shows up as water damage traced to the up-slope side of a chimney or skylight. The failure is rarely the cricket structure itself; it is usually the flashing joint where the cricket meets the masonry, or the absence of any cricket on a wide chimney. Watch for these signs:
- Dark staining, moss, or streaking on the shingles directly behind (up-slope of) the chimney.
- A recurring interior leak near the chimney chase that returns after each storm.
- Granule loss fanning out behind the chimney where trapped water sits.
- Rust, open seams, or lifted edges on the cricket metal.
- Sealant smeared over a flashing gap instead of metal cut into a masonry reglet.
Because the leak and the flashing usually fail together, a proper fix pairs the cricket with new step and counter flashing. See the failure modes in our guide to the signs of failed chimney flashing.
What a cricket costs and who builds it
Cricket cost depends on chimney width, roof pitch, and the flashing metal, so a single national figure is misleading. A small aluminum-covered cricket added during a reroof is a modest line item, while a wide copper cricket framed onto a steep roof costs substantially more. The drivers below explain why two quotes for the same house can differ.
| Cost driver | Effect on price |
|---|---|
| Chimney width (W) | Wider chimneys need a larger cricket and more material |
| Roof pitch | Steeper roofs raise both the required height and the labor to work safely |
| Flashing metal | Aluminum is cheapest; galvanized mid-range; copper the most expensive |
| New build vs retrofit | Framing during a reroof costs less than cutting one into an intact roof |
The work is roofing carpentry plus flashing, so a licensed roofer, not a chimney sweep, typically builds it, often during a reroof when the deck is open. For a full 2026 cost breakdown and the ten-step build, see our step-by-step chimney cricket build and install cost.
Frequently asked questions
Is a roofing cricket the same as a saddle?
Yes. Cricket and saddle are two names for the same part: a small peaked ridge built on the up-slope side of a chimney or wide penetration to divert water around it. Regions and trades favor one term over the other, but they describe the identical framed structure. Some crews reserve saddle for larger or masonry-backed versions, though the code and most references treat them as interchangeable.
Does every chimney need a cricket?
No. Under IRC R1003.20, a cricket is required only where the chimney measures more than 30 inches parallel to the ridge and does not intersect the ridgeline. Narrow chimneys and those that straddle the ridge already shed water to both sides, so code does not require one. On low-slope roofs, adding a cricket to a narrower chimney can still reduce ponding and is often worthwhile.
What slope should a roofing cricket be?
A cricket’s height is set by IRC Table R1003.20, which gives minimum height as a fraction of chimney width based on roof slope: 1/2 of the width at 12:12, 1/4 at 6:12, and 1/6 at 4:12, among other values. Steeper roofs need a taller cricket. On flat and low-slope roofs, crickets are commonly pitched steeper than the main field so water clears.
Do skylights need a cricket?
Sometimes. A wide skylight on a low slope can dam water on its up-slope side the same way a chimney does, so a cricket or a factory-flashed diverter is used to split the flow. Narrow skylights on steeper roofs usually shed water fine with standard step flashing. The wider the unit and the lower the pitch, the more a cricket helps.
Can a cricket be added to an existing roof?
Yes, though it is easier during a reroof. Adding a cricket to an intact roof means cutting back shingles behind the chimney, framing and decking the cricket, running new ice-and-water membrane, and installing fresh step and counter flashing. Because the flashing joint has to be rebuilt either way, most contractors schedule a retrofit cricket alongside a reroof or a chimney flashing repair.
What happens if a wide chimney has no cricket?
Water piles up against the back wall of the chimney and works under the flashing. Over time that causes deck rot behind the chimney, mortar and masonry decay, and recurring interior leaks near the chase. Debris also collects in the flat trap, holding moisture longer. On a chimney wider than 30 inches, a missing cricket is both a code deficiency and a predictable long-term leak.