Chimney Cricket Code, Sizing & Cost: 2026 Saddle Guide
The spot where a chimney passes through a sloped roof is one of the most leak-prone areas on any home. When rain or melting snow runs down the roof, a wide chimney acts like a dam and traps water against its back wall.
Over time, that trapped water can:
A chimney cricket, also called a chimney saddle, solves this. It's a small peaked ridge built on the uphill side of the chimney that splits the water and sends it around both sides.
This guide focuses on crickets: when code requires one, how to size it, how it's built, and what it costs. If you're dealing with an active leak or need to understand step and counter flashing, start with the Chimney Flashing Repair Guide.
Related guides:
When Building Code Requires a Chimney Cricket
The 30-Inch Rule
The International Residential Code (IRC), adopted by most U.S. jurisdictions, requires a cricket when both of these are true:
The chimney is more than 30 inches wide, measured parallel to the roof ridge (across the slope).
The chimney does not intersect the ridge. A chimney that sits on the ridge line doesn't trap water, so no cricket is required.
The requirement appears in two places in the IRC:
Section R903.2.2 (roof assemblies) requires the cricket and says it must be covered with sheet metal or the same material as the roof.
Section R1003.20 (masonry chimneys) sets the minimum cricket height and requires the cricket-to-chimney joint to be flashed and counter-flashed like any other roof-chimney joint.
Your local building department has the final word, since some areas amend the IRC.
Narrower Chimneys
Chimneys 30 inches wide or less can legally use a simple flat back pan instead of a cricket. But many experienced roofers still recommend a cricket on chimneys 24 to 28 inches wide if:
The roof pitch is steeper than 6:12
The home is in a heavy-snow region
The chimney has a history of leaks on the uphill side
How to Size a Chimney Cricket
Minimum Height by Roof Pitch
IRC Section R1003.20 sets the minimum cricket height as a fraction of the chimney's width. The steeper the roof, the taller the cricket.
Roof Slope | Minimum Cricket Height | Example: 36-Inch-Wide Chimney |
|---|
3:12 | 1/8 of chimney width | 4.5 inches |
4:12 | 1/6 of chimney width | 6 inches |
6:12 | 1/4 of chimney width | 9 inches |
8:12 | 1/3 of chimney width | 12 inches |
12:12 | 1/2 of chimney width | 18 inches |
Match or Exceed the Roof Pitch
A cricket that's too flat lets snow and wet leaves pack into its valleys. That creates a pocket of moisture that freezes and thaws under the flashing.
Rule of thumb: The cricket's slope should match or exceed the main roof pitch. On an 8:12 roof, frame the cricket at 8:12 or steeper so water drains off quickly.
How a Chimney Cricket Is Built
A good cricket takes coordination between roof framers and sheet metal installers. It's built in four layers.
1. Wood Framing and Decking
A center ridge board runs from the middle of the chimney's back wall up the roof slope.
Rafters or angled blocking create the two valley slopes.
The frame is covered with 1/2-inch or 5/8-inch plywood or OSB, matching the surrounding roof deck.
The frame must be fastened securely into the roof rafters, never just attached to the sheathing.
2. High-Temperature Ice and Water Shield
Before any metal goes on, the whole cricket and the surrounding valleys are covered with a continuous high-temperature self-adhering membrane. It should extend:
The high-temperature rating matters because chimneys carry heat from active fireplaces and flues, which can break down standard membranes.
3. The Cricket Covering
Code allows two covering options:
Shingles over metal valley liners: The standard choice for asphalt shingle roofs.
A custom soldered metal saddle: Typically 16-ounce copper, 24-gauge galvanized steel, or 0.032-inch aluminum. A soldered or welded saddle offers the best leak protection because it has no fasteners in the areas where water flows.
4. Flashing Where the Cricket Meets the Chimney
The cricket-to-chimney joint is flashed the same way as the rest of the chimney: step flashing woven into the roofing, with counter flashing set into the mortar joints above it. For cricket installs, key details include:
Counter flashing set into a reglet, a slot about 1 inch deep cut into the mortar joint
Lead plugs or lead anchors to secure it, sealed with polyurethane or silicone masonry sealant
At least 4 inches of overlap over the flashing below
For a full explanation of how step, counter, and base flashing work together, see the Chimney Flashing Repair Guide.
Cricket Options Compared
Feature | Standard Shingled Cricket | Soldered Metal Saddle | Flat Back Pan (No Cricket) |
|---|
Code compliance | Meets IRC for chimneys more than 30" wide | Meets IRC for chimneys more than 30" wide | Allowed only on chimneys 30" wide or less |
Installed cost | $650 – $1,400 (during a roof replacement) | $1,400 – $2,800 (copper or zinc) | $350 – $600 (basic aluminum flashing) |
Lifespan | 25 – 35 years (matches the shingles) | 50 – 80+ years (copper or heavy-gauge metal) | 10 – 15 years (prone to clogs and rust) |
How it sheds water | Two valleys divert water around the sides | One seamless metal surface | Flat surface that collects standing water and leaves |
Snow and ice resistance | High; the angled ridge prevents snow buildup | Very high; smooth metal sheds ice easily | Poor; snow packs against the brick |
Best for | Standard asphalt shingle roofs | Historic brick, slate, and cedar roofs | Small chimneys only |
What a Chimney Cricket Costs
During a Roof Replacement: $650 – $1,400
This is the most affordable time to add a cricket. The roof deck is already exposed, and the crew has materials on site.
Retrofit on an Existing Roof: $1,200 – $2,400
Adding a cricket to an existing roof takes much more labor. Contractors must:
Carefully remove the surrounding shingles
Frame and deck the cricket
Re-flash the chimney and cut new mortar reglets
Weave in new shingles that blend with the existing roof
Copper Upgrade: Add $600 – $1,500
Hand-soldered copper adds $600 to $1,500, depending on current copper prices.
Common Installation Mistakes
Relying on Caulk Instead of Real Flashing
The biggest mistake is using surface caulk or roofing mastic instead of setting counter flashing into the mortar. Caulk exposed to sunlight dries out, cracks within 24 to 36 months, and pulls away from the brick.
Nails in the Valleys
Water running down the cricket will find any nail hole in the valley, rust the nail, and leak into the attic. Fasteners belong only on the upper outer edges of the flashing.
Heat Loss Around the Chimney
In snowy regions, warm air escaping from the house around the chimney can melt snow on the roof. That meltwater refreezes into ice dams behind the chimney. Good attic insulation and air sealing around the chimney help prevent this.
Crickets on Historic Homes
Why Mortar Choice Matters
Homes built before 1940 usually have soft clay bricks set in flexible lime-based mortar. If a contractor uses hard, modern Portland cement mortar (such as Type M or S) when setting counter flashing, the rigid mortar stresses the softer brick during freeze-thaw cycles. The brick face can then crack and flake off (spall).
Best Practices
Pack flashing reglets with soft, flexible Type N or historic lime-sand mortar.
Secure counter flashing with lead wedges or soft lead plugs.
Finish with a breathable silicone or polyurethane masonry sealant.
Maintenance and Inspection
Even a well-built cricket needs regular checkups as it expands and contracts over the years. Schedule a roof inspection every spring and check:
Sealant: Make sure the sealant along the counter flashing is still flexible and bonded to the brick. Clean out and reseal any cracks or dried-out spots.
Debris: Clear twigs, pine needles, and windblown debris from the cricket's peak and valleys, where they can trap standing water.
Final Thoughts
A chimney cricket is a small structure that prevents one of the most common and damaging roof leaks. Keep these points in mind:
Code requires a cricket on chimneys more than 30 inches wide that don't sit on the ridge.
Size it by roof pitch, and frame it at least as steep as the roof.
Adding one during a roof replacement costs far less than a retrofit.
Proper flashing, not caulk, is what keeps it watertight.
When you are ready to get estimates from licensed contractors in your area, contact Home Upgrade Pros or call: (702) 620-6514 to connect with professionals who offer free no-obligation assessments.
Frequently Asked Questions
At what chimney width does building code require a chimney cricket?
Under the International Residential Code (Sections R903.2.2 and R1003.20), a cricket is required on the uphill side of any chimney more than 30 inches wide, measured parallel to the roof ridge, unless the chimney intersects the ridge. Many roofers also recommend crickets on chimneys 24 to 28 inches wide on steep roofs to prevent debris buildup.
How tall should a chimney cricket be?
IRC Section R1003.20 sets the minimum height as a fraction of the chimney's width, based on roof pitch:
3:12 roof: 1/8 of the width
4:12 roof: 1/6 of the width
6:12 roof: 1/4 of the width
8:12 roof: 1/3 of the width
12:12 roof: 1/2 of the width
For example, a 36-inch chimney on a 6:12 roof needs a cricket at least 9 inches tall.
Can a chimney cricket be installed on an existing roof without replacing the whole roof?
Yes. A roofing contractor can retrofit a cricket onto an existing roof by:
Removing the shingles around the chimney
Framing the cricket
Installing ice and water shield
Adding step and counter flashing
Weaving matching shingles back into the surrounding roof
Why is high-temperature ice and water shield required around chimneys?
Chimneys carry heat from wood-burning fireplaces, gas appliances, and furnaces. Standard rubberized asphalt underlayment softens and breaks down above about 180°F. High-temperature membranes are designed to handle continuous temperatures up to about 250°F, keeping a watertight seal against warm masonry.
Should a chimney cricket be metal or shingled?
Code allows either sheet metal or the same material as the roof covering.
Shingled cricket: The standard choice for asphalt shingle roofs. It costs about $650 to $1,400 during a roof replacement and lasts 25 to 35 years, about as long as the shingles.
Soldered metal saddle: Usually copper, galvanized steel, or aluminum. It costs about $1,400 to $2,800, lasts 50 to 80+ years, and has no fasteners where water flows. It's the preferred choice for historic brick, slate, and cedar roofs.
