A roof cricket is a raised, wedge-shaped structure installed on the uphill side of a chimney or another wide roof penetration. Its purpose is to divide the flow of rainwater and melting snow so moisture can move around the obstruction instead of collecting behind it.
Crickets are easy to overlook from the ground, but they are an important part of roof drainage. In Greene, NY, where roofs may be exposed to heavy rain, repeated freeze-thaw cycles, and winter snow, this detail can help reduce moisture problems near chimneys and large roof features.
What does a roof cricket look like?
A cricket resembles a small peaked roof built into the main roof. The ridge of the cricket generally runs perpendicular to the main roof ridge, creating two sloped sides that direct water toward the left and right sides of the chimney or penetration.
It is usually framed over the roof deck and covered with roofing material, sheet metal, or a combination of both. The cricket also works with flashing, which seals the joint between the roof and the chimney.
A cricket is not the same as a chimney cap. A chimney cap covers the top of the chimney and helps keep rain, snow, and debris out of the flue. A cricket is located at the base of the chimney, where the chimney passes through the roof.
Why is a cricket needed?
A chimney interrupts the natural downhill path of water. Without a cricket, rain and melting snow can flow directly into the area behind the chimney, where the roof surface meets the masonry.
That area is vulnerable because:
- Water may collect instead of draining efficiently.
- Leaves and roof debris can become trapped.
- Snow may build up in a pocket behind the chimney.
- Ice can form during repeated freezing and thawing.
- Flashing may be exposed to prolonged moisture.
- Water can eventually reach the roof deck or attic.
The cricket changes the roof shape so water is divided and directed around the obstruction. This reduces standing water and gives flashing a better chance to perform as intended.
How does a roof cricket help during winter?
A cricket can be particularly useful during snowy winters because it helps prevent snow from remaining tightly packed behind a chimney. Snow that melts and refreezes in this area can create a localized ice dam.
An ice dam forms when melting snow runs down a roof and freezes near a colder roof edge or obstruction. Water held behind the ice can move beneath roofing materials or through weak points in the flashing.
A cricket does not prevent every ice dam. Roof insulation, attic air sealing, ventilation, roof slope, sun exposure, and weather conditions all influence snow and ice behavior. However, a properly designed cricket helps keep water moving around the chimney rather than allowing it to concentrate directly behind it.
Which roof penetrations need a cricket?
Crickets are most commonly associated with chimneys, but the same principle can apply to other wide obstructions. The need depends on the size, location, shape, roof slope, and drainage design of the penetration.
In residential construction, commonly used building-code provisions call for a cricket or saddle on the ridge side of a chimney or penetration wider than 30 inches when measured across the roof slope. Smaller penetrations may not require a framed cricket, but they still need properly designed flashing and underlayment.
Large skylights, rooftop equipment, masonry features, and other broad projections may also require a raised drainage detail. A low-profile saddle, tapered insulation, or another engineered solution may be used depending on the roof system.
The key question is not simply whether an object is called a chimney or skylight. The key question is whether the obstruction interrupts drainage enough to create a vulnerable collection point.
What is the difference between a cricket and a saddle?
The terms are sometimes used interchangeably, but they can describe slightly different shapes.
A cricket is generally a peaked, two-sided structure that actively divides water and snow around an obstruction. It looks like a small gable roof behind the chimney.
A saddle may be a similar structure, but the shape can be lower, simpler, or more tapered. In some roofing systems, “saddle” is used as a general term for a drainage structure placed behind a penetration.
Both serve the same basic purpose: moving water away from the uphill side of an obstruction and toward drainage paths on either side.
How does flashing work with a cricket?
A cricket cannot replace flashing. The two systems must work together.
Flashing forms water-resistant transitions where the roof meets the chimney. It may include base flashing, step flashing, counterflashing, and metal components installed over or beside the cricket. Underlayment or a self-sealing membrane may provide an additional layer beneath the visible roofing.
The upper portion of the cricket must be integrated with the chimney flashing so water cannot enter at the ridge or side joints. The lower ends must discharge water onto the roof surface rather than into a concealed gap.
Problems can occur when a cricket is present but the flashing is poorly shaped, corroded, loose, cut incorrectly, or covered by roofing material in a way that blocks drainage. A cricket is a drainage feature, not a substitute for careful water-shedding details.
What are signs of a problem behind a chimney?
Some warning signs can be seen inside the home or attic rather than from the ground. Possible indicators include:
- Brown stains on ceilings or upper walls near the chimney.
- Damp insulation or darkened roof sheathing.
- Peeling paint near the chimney chase.
- Musty odors after rain or snowmelt.
- Damaged masonry joints near the roofline.
- Rusted metal flashing.
- Shingles that curl, lift, or deteriorate behind the chimney.
- Repeated ice buildup in the same area.
A leak may not appear directly below the chimney because water can travel along rafters, roof sheathing, insulation, or framing before becoming visible.
Roof access can also be hazardous, especially when shingles are wet, snow-covered, or icy. Inspection of a cricket and its flashing may require safe access and a clear view of the uphill side of the penetration.
Can an existing chimney have a cricket added later?
In many cases, a cricket can be added during roof replacement or as part of a roof repair, but the exact approach depends on the roof framing, chimney width, roof pitch, roofing material, and available space.
Adding one may involve modifying the roof deck, installing framing, extending or replacing underlayment, and rebuilding portions of the flashing. The cricket must be proportioned so it sheds water rather than creating another low spot.
A narrow roof area, nearby valley, dormer, or second penetration can make the design more complicated. Crowded roof layouts often need extra attention because water and snow may be directed toward one another.
Why does this matter for older homes?
Older houses may have chimneys, additions, dormers, and roof sections built at different times. These changes can create irregular drainage paths. Some older chimney details rely heavily on aging mortar, metal flashing, or roofing layers that have been repaired repeatedly.
A roof cricket is not automatically required on every older chimney, but its absence can be worth evaluating when the area behind the chimney repeatedly leaks, holds snow, or collects debris.
For area households, seasonal observation is useful. Checking the attic after a heavy rain and looking for recurring moisture after snowmelt can reveal problems before they become visible as major interior damage. The most reliable roof drainage is a combination of sound design, continuous flashing, intact roofing, and a clear path for water to leave the roof.
