Roof Cricket and Saddle Code in Georgia
Georgia requires a cricket behind any chimney wider than 30 inches. This guide covers the code trigger, construction methods, flashing integration, height calculations, and the damage patterns that develop when crickets are missing.
Certified by Industry-Leading Manufacturers
IRC R903.2.2: The 30-Inch Cricket Requirement
IRC Section R903.2.2 establishes a clear trigger: any chimney that measures more than 30 inches wide on the side perpendicular to the roof slope requires a cricket on the uphill side. Georgia adopts this provision through the Department of Community Affairs with no state-level amendment that weakens or removes it. The requirement applies to every residential building permit issued under the IRC in Georgia.
The code reads: "In areas where the average daily temperature in January is 25 degrees F or less or where there is a possibility of ice forming along the eaves causing a backup of water, a cricket or saddle shall be installed on the ridge side of any chimney or penetration greater than 30 inches wide as measured perpendicular to the slope." Georgia's climate zone triggers this provision across the northern third of the state, and metro Atlanta falls within the applicable zone.
A cricket (also called a saddle) is a peaked structure built behind the chimney that diverts water around it rather than allowing water to pool against the uphill face. The geometry creates two sloped planes that meet at a ridge, channeling water to either side of the chimney. Without this diverter, the flat junction between the chimney masonry and the roof plane traps water, debris, and ice.
The 30-inch measurement targets the chimneys large enough to create a meaningful water trap. A chimney that measures 24 inches wide creates a small pocket that most roof slopes flush clean during rain. A chimney that measures 36, 48, or 60 inches wide creates a dam that holds gallons of standing water after every storm. The homes in Buckhead, Johns Creek, and Sandy Springs often feature oversized masonry chimneys that measure 48 to 72 inches across. Every one of them requires a cricket.
Building inspectors in Gwinnett County, Fulton County, Cobb County, and DeKalb County verify cricket installation during both the pre-cover inspection (before shingles go on) and the final inspection. A chimney that triggers the 30-inch threshold without a cricket fails the inspection. For the full scope of Georgia's residential roofing code, see our Georgia residential roofing code guide.
How Crickets Are Built: Materials and Framing
The IRC allows several construction methods for roof crickets. The method depends on the chimney width, the roof pitch, and the roofing material. All methods share the same goal: create a peaked diverter that sheds water to both sides of the chimney.
Framed Plywood Cricket
The most common method on residential asphalt shingle roofs in metro Atlanta. The crew builds a triangular frame from 2x4 lumber, sheathes it with 1/2-inch CDX plywood or 7/16-inch OSB, applies underlayment over the sheathing, and then shingles the cricket to match the field roof. The cricket ridge runs from the peak of the chimney's uphill face straight back to the main roof plane. The two sloped sides of the cricket meet at this ridge and shed water to the left and right.
Framing dimensions depend on the chimney width and the main roof pitch. The cricket must be steep enough to prevent water and debris accumulation. A common rule uses a cricket pitch that matches the main roof pitch at a minimum. For a chimney that sits on a 6:12 roof, the cricket slopes should be at least 6:12. Flatter cricket slopes trap debris and standing water, defeating the purpose of the diverter.
Sheet Metal Cricket
A full sheet metal cricket uses bent metal (galvanized steel, aluminum, or copper) to form the peaked diverter without a wood substructure. Metal crickets are common on steep roofs where the cricket is visible from the ground and the homeowner wants a clean, permanent installation. Copper crickets on high-end homes in Buckhead provide a 50+ year lifespan and match the copper flashing and copper accent roofing common in that market.
Metal crickets require soldered seams (for copper) or mechanically locked standing seams (for steel and aluminum) to prevent water entry at the joints. The base of the metal cricket integrates with the step flashing and counter flashing system at the chimney face.
Pre-Manufactured Cricket Kits
Several manufacturers produce pre-formed cricket assemblies in standard sizes (30-inch, 36-inch, and 48-inch chimney widths). These kits include the plywood panels, ridge cap, and flashing components. They speed installation on standard chimney sizes but do not fit the oversized chimneys common on luxury homes. For chimneys wider than 48 inches, custom fabrication remains the standard practice.
.jpg)
| Construction Method | Materials | Best Application | Lifespan |
|---|---|---|---|
| Framed plywood + shingles | 2x4 framing, CDX plywood, underlayment, matching shingles | Standard residential, moderate-pitch roofs | Matches roof (20-30 years) |
| Sheet metal (copper) | 16 oz or 20 oz copper sheet, soldered seams | Premium homes, steep roofs, architectural accent | 50+ years |
| Sheet metal (galvanized) | 26-gauge galvanized steel, mechanical seams | Low-visibility areas, commercial crossover | 20-25 years |
| Pre-manufactured kit | Factory-formed panels with flashing | Standard chimney sizes (30-48" width) | Matches roof (20-30 years) |
Cricket Height and Slope Calculations
The IRC does not specify a minimum height for the cricket ridge, but the code's intent and manufacturer installation guides establish the practical standard: the cricket ridge must be high enough to prevent water from overtopping it during heavy rain. The calculation depends on the chimney width and the main roof pitch.
The Basic Formula
Cricket ridge height equals one-half the chimney width multiplied by the tangent of the main roof pitch angle. For a 48-inch chimney on a 6:12 roof (26.6 degrees), the calculation produces: (48/2) x tan(26.6) = 24 x 0.5 = 12 inches. The cricket ridge sits 12 inches above the main roof plane at the chimney face.
This formula assumes the cricket pitch matches the main roof pitch. Some contractors build steeper crickets to accelerate water shedding, which increases the ridge height. A steeper cricket also reduces the surface area where debris can accumulate, which matters on homes surrounded by Georgia's mature hardwood canopy.
Width-Based Sizing Reference
| Chimney Width | Cricket Ridge Height (6:12 roof) | Cricket Ridge Height (8:12 roof) | Cricket Ridge Height (12:12 roof) |
|---|---|---|---|
| 30" | 7.5" | 10" | 15" |
| 36" | 9" | 12" | 18" |
| 48" | 12" | 16" | 24" |
| 60" | 15" | 20" | 30" |
| 72" | 18" | 24" | 36" |
The table shows that large chimneys on steep roofs produce substantial cricket structures. A 72-inch chimney on a 12:12 roof requires a cricket ridge that stands 36 inches above the roof plane. This is not a small detail. It is a structural component that requires proper framing, sheathing, and integration with the chimney flashing system.
A 48-inch chimney on a 6:12 roof needs a cricket that stands 12 inches above the roof plane. Skip it, and water pools against masonry on every rain event.
Our team at 1 Source Roofing measures every chimney during the pre-project inspection and calculates the required cricket dimensions before writing the scope of work. The homeowner sees the cricket specification on the proposal, and our crew builds it to the calculated dimensions. This prevents the field shortcuts that produce undersized crickets.
Cricket Flashing Integration With the Chimney System
The cricket does not work in isolation. It must integrate with the chimney's step flashing, counter flashing, and base flashing to create a continuous water barrier. A well-built cricket with poor flashing integration still leaks. The flashing ties the cricket to the chimney masonry and to the main roof plane.
Step Flashing at the Cricket Sides
Step flashing runs along both sides of the chimney where the masonry meets the roof. At the cricket, the step flashing transitions from the main roof plane onto the cricket's sloped surface. Each piece of step flashing must overlap the piece below it by at least 2 inches, and the flashing must extend at least 4 inches up the chimney face and 4 inches onto the roof surface. For detailed step flashing standards, see our roof flashing code guide.
Base Flashing at the Cricket-Chimney Junction
The base flashing covers the junction where the cricket ridge meets the chimney face. This is the highest point of the cricket and the location most vulnerable to water entry. The base flashing must extend at least 6 inches up the chimney face above the cricket ridge and must wrap over the cricket ridge by at least 4 inches on each side. The flashing tucks under the counter flashing (set into the mortar joint) to create a two-layer defense.
Counter Flashing
Counter flashing is set into the chimney's mortar joints (reglets) and bends down over the top edge of the step flashing and base flashing. This layer prevents water from running behind the primary flashing. On the cricket, the counter flashing covers the base flashing at the ridge and transitions down both sides to meet the step flashing counter flashing. Our chimney flashing installation guide covers the full counter flashing system.
Cricket-to-Roof Transition
Where the cricket's sloped surfaces meet the main roof plane, the shingles on the cricket must weave into the field shingles without creating a dam or gap. The underlayment from the cricket overlaps the main roof underlayment by at least 6 inches. The shingles follow the standard shingle installation pattern with staggered joints that prevent water tracking along a single seam.
A properly flashed cricket creates four layers of water defense at the chimney: the cricket structure (diverts water), the primary flashing (seals the cricket-to-chimney joint), the counter flashing (covers the primary flashing edge), and the shingle coverage (sheds surface water before it reaches the flashing).
Need a Cricket Built or Repaired Behind Your Chimney?
1 Source Roofing builds code-compliant crickets on every chimney that triggers the 30-inch requirement. We measure, calculate, frame, flash, and shingle each cricket to IRC R903.2.2 standards.
Call (404) 277-1377What Happens When a Cricket Is Missing: Damage Patterns
The damage from a missing cricket develops over months and years. It starts at the junction between the chimney's uphill face and the roof plane, where water has no path to escape. Metro Atlanta's 50 inches of annual rainfall, combined with heavy debris from pine straw and hardwood leaves, accelerates every failure mode.
Water Damming
Without a cricket, water flowing down the roof slope hits the chimney's uphill face and has nowhere to go except sideways along the base of the chimney. On wide chimneys (48 inches and above), the water volume overwhelms the step flashing and pushes under the shingles. Standing water sits against the masonry during and after every rain event. In Georgia's summer thunderstorm season, this happens multiple times per week.
Debris Accumulation
Pine straw, oak leaves, and granular shingle debris collect behind the chimney in the pocket where the cricket should be. This debris acts as a sponge that holds moisture against the roof surface between rain events. The debris also dams water flow, forcing it higher up behind the chimney than the rainfall alone would produce. On homes in heavily wooded areas of Roswell, Alpharetta, and Marietta, the debris accumulation behind an unprotected chimney can reach 6 inches deep within a single fall season.
Deck Rot and Framing Damage
Persistent moisture at the chimney base penetrates the underlayment and saturates the roof deck. Plywood and OSB lose structural integrity when exposed to sustained moisture. Within 3 to 5 years, the deck behind the chimney softens, delaminates, and requires replacement. The framing members (rafters and headers) beneath the deck absorb moisture from the saturated sheathing. Framing replacement behind a chimney is a structural repair that costs thousands of dollars beyond the cricket that would have prevented it.
Interior Leak Progression
The first interior sign of a missing cricket is a water stain on the ceiling near the chimney. The stain grows with each rain event. Homeowners often mistake this for a flashing failure, but the root cause is the absence of the cricket that should divert water before it reaches the flashing. Repairing the flashing without adding the cricket fixes nothing because the water continues to pool at the same location.
Every chimney leak we investigate starts the same way: no cricket, trapped water, rotted deck. The fix costs ten times more than the cricket would have cost during the original installation.
How Insurance Adjusters Evaluate Cricket Damage
Insurance adjusters in Georgia distinguish between storm damage and maintenance-related damage. A missing cricket creates a classification problem for homeowners filing storm damage claims. The adjuster's evaluation follows a predictable pattern.
When the adjuster inspects the chimney area and finds water damage but no cricket, the adjustment report categorizes the damage as "pre-existing" or "maintenance-related." The reasoning: the cricket is a code-required component. Its absence constitutes deferred maintenance. Any water damage caused by the missing cricket predates the storm event and falls outside the policy's covered peril (typically wind, hail, or falling objects).
This classification reduces or eliminates the payout for chimney-area damage. The homeowner expected the claim to cover the leak repair, deck replacement, and interior water damage. The adjuster covers none of it because the root cause (missing cricket) is not a storm event.
The Counter-Argument
A homeowner can argue that the storm intensified the damage beyond what the missing cricket alone would cause. High wind-driven rain can push water volumes that overwhelm even proper flashing. Hail can crack the masonry or damage the flashing at the chimney base. These are covered perils. The key is documenting the storm damage separately from the pre-existing condition. Our insurance claims team helps homeowners present this documentation to adjusters. See our adjuster meeting guide for preparation steps.
The Prevention Strategy
The strongest position for any future insurance claim is a roof with all code-required components installed. A cricket behind every chimney that triggers the 30-inch threshold removes the "deferred maintenance" argument from the adjuster's evaluation. When storm damage does occur, the adjuster evaluates the damage against a code-compliant installation, and the claim covers the full scope of the storm's impact. For more on navigating Georgia insurance claims, see our denied claims guide.
How 1 Source Builds Crickets on Every Qualifying Chimney
Our team measures every chimney during the initial roof inspection. If the chimney exceeds 30 inches, the cricket appears on the scope of work with calculated dimensions. We do not treat crickets as optional upgrades or add-on line items. The code requires them, and our standard includes them.
Our construction sequence for framed plywood crickets follows six steps:
- Measurement: Measure chimney width and main roof pitch. Calculate cricket ridge height using the formula above.
- Framing: Cut and install 2x4 ridge board and sloped supports. Anchor framing to existing rafters and roof deck with structural screws.
- Sheathing: Cut CDX plywood panels to match the cricket geometry. Fasten to framing with 8d ring-shank nails at 6-inch spacing along edges.
- Underlayment: Apply synthetic underlayment over the cricket sheathing, overlapping the main roof underlayment by at least 6 inches on all sides.
- Flashing: Install base flashing at the cricket-chimney junction, step flashing along the sides, and counter flashing into the mortar joints. All flashing extends a minimum of 4 inches onto each surface.
- Shingles: Shingle the cricket to match the field roof. Weave cricket shingles into the main roof shingle courses. Apply roofing cement at all flashing-to-shingle transitions.
On premium projects, we build copper sheet metal crickets with soldered seams. These installations pair with our copper chimney flashing and copper roofing accent work. The result is a cricket that outlasts the roof by decades.
Every cricket we build passes the pre-cover inspection before shingles go on and the final inspection after the project is complete. We document the cricket installation with photographs that go into the homeowner's project file, providing evidence of code compliance for future insurance claims or resale inspections.
Roof Cricket Code: Frequently Asked Questions
Answers to common questions about roof cricket requirements, construction, and inspection standards in Georgia.
When does Georgia code require a roof cricket behind a chimney?
IRC Section R903.2.2, which Georgia adopts, requires a cricket (also called a saddle) on the ridge side of any chimney that measures more than 30 inches wide. The 30-inch measurement applies to the dimension perpendicular to the roof slope. Any chimney wider than 30 inches across the face that intersects the roof must have a cricket to divert water around it.
What happens when a chimney lacks a required cricket?
Water pools behind the chimney where the roof slope meets the uphill face. This trapped water penetrates the flashing, saturates the roof deck, and rots the framing beneath the chimney. Over time, the leak migrates through the ceiling below. Insurance adjusters in Georgia often classify this as deferred maintenance rather than storm damage because the missing cricket is a code violation that predates the claim event.
What materials can be used to build a roof cricket in Georgia?
The IRC allows crickets built from plywood or OSB sheathing framed to create the diverter shape, covered with metal flashing (galvanized steel, aluminum, or copper) or with the same roofing material as the main roof. On asphalt shingle roofs, most Georgia contractors build a plywood cricket, apply underlayment, and shingle over it to match the field. On steeper roofs or premium homes, a full metal cricket made from sheet copper or lead-coated copper provides superior durability.
Will a missing cricket cause a roof inspection to fail in Georgia?
Yes. Building inspectors in Gwinnett, Fulton, Cobb, and DeKalb counties check for crickets during the pre-cover and final roof inspections when the chimney exceeds 30 inches in width. A missing cricket on a chimney that triggers the code requirement will result in a failed inspection and a correction notice. The contractor must build and flash the cricket before the inspector will approve the installation.
Explore More Georgia Roofing Code Guides
- Georgia Residential Roofing Code Guide
- Roof Flashing Code in Georgia
- Kickout Flashing Code in Georgia
- Drip Edge Code Requirements
- Chimney Flashing Installation Guide
- Copper Roofing Code in Georgia
- Roofing Inspection Checklist
- Asphalt Shingle Requirements
- Roof Replacement Services
- Insurance Claims Assistance