On a roof inspection in Vienna last fall, we peeled back the shingles behind a 48-inch-wide brick chimney and found what we expected: two layers of rotted decking, black mold on the rafters, and flashing that had given up years ago. The homeowner had been patching ceiling stains for three winters. The root cause was simple, no cricket behind the chimney.
That missing cricket turned a $500 addition during the original roof installation into a $6,000 repair bill that included new decking, framing, mold remediation, and interior drywall work. It's one of the most preventable failures in residential roofing.
The Problem a Cricket Solves
A chimney sitting on a sloped roof creates a dam. Water flowing down the slope hits the backside of the chimney and has nowhere to go. It pools in the valley formed between the roof surface and the chimney wall. Leaves, pine needles, and roofing granules collect there, holding moisture against the roof surface.
In Northern Virginia, this problem intensifies in three seasons:
Spring and summer thunderstorms dump heavy volumes in short bursts. The pooling behind an uncricketed chimney overwhelms flashing designed for normal water flow, not standing water. Fall leaf drop packs the space behind the chimney with organic debris. In neighborhoods surrounded by oaks, maples, and pines, most of Fairfax County, frankly, this debris layer can be three inches deep by November. That wet mat accelerates shingle and decking deterioration. Winter freeze-thaw turns pooled water into ice. The chimney mass absorbs heat from the fireplace and interior walls, creating a melt-refreeze cycle directly behind it. Ice pushes under step flashing, water follows, and leaks appear on interior walls and ceilings near the chimney.A chimney cricket eliminates all three scenarios by reshaping the flat collection zone into a peaked diverter that splits water flow around both sides of the chimney.
What a Cricket Looks Like and How It Works
A chimney cricket is a small peaked structure, essentially a miniature gable roof, built on the upslope side of the chimney. The ridge runs from the chimney face back toward the roof slope, and two angled surfaces shed water to the left and right.
Think of it as a tent pitched behind the chimney. Water hits the tent peak and runs off to both sides, rejoining the normal downslope flow well clear of the chimney walls. Debris slides off the angled surfaces instead of accumulating in a flat dead zone.
The cricket's size depends on two factors: the width of the chimney and the pitch of the surrounding roof. A wider chimney needs a larger cricket. A lower-pitched roof (common on ranch-style homes in Springfield, Burke, and Annandale) creates more severe pooling, requiring a cricket even on narrower chimneys.
Virginia Code Requirements
The Virginia Residential Code is clear: a chimney cricket is required when the chimney dimension perpendicular to the roof slope exceeds 30 inches.
Most standard masonry chimneys in Northern Virginia, especially the double-flue brick chimneys found on colonials throughout McLean, Great Falls, and Oakton, measure 36 to 48 inches across. These chimneys absolutely require a cricket by code.
Smaller chimneys serving a single gas fireplace flue may fall under 30 inches and not technically require one. Even so, we recommend a cricket on any chimney wider than 20 inches because the debris accumulation and pooling problem exists regardless of code thresholds.
A note about older homes: Many homes built before the cricket code requirement was adopted lack them entirely. If your home was built in the 1970s or 1980s and has a large chimney, there's a strong probability no cricket was installed. This is one of the first things we check on any roof inspection.Three Cricket Construction Methods
Framed and Shingled
The most common residential approach. A small frame is built from dimensional lumber, sheathed with plywood, covered with ice and water shield, and finished with shingles that match the surrounding roof. CertainTeed Landmark Pro shingles on the cricket blend smoothly with the rest of the roof.
Advantages: Invisible from the ground, cost-effective, integrates with the shingle system warranty Best for: Standard residential chimneys on moderately sloped roofsSheet Metal
A pre-formed or field-fabricated metal cricket (galvanized steel, aluminum, or copper) provides superior water shedding. Metal crickets are smooth surfaces that shed debris more efficiently than shingles and have no granule layer to deteriorate.
Advantages: Longest lifespan, best debris shedding, excellent for low-slope situations Best for: Low-slope roofs, extra-wide chimneys, or homeowners who want maximum durabilityEnglert metal roofing products can be used for custom cricket fabrication on homes already using metal roofing systems, maintaining a consistent material profile across the entire roof.
Hybrid (Metal Top, Shingled Sides)
Combines a metal ridge and peak with shingled side slopes. This approach puts the hardest-working material at the highest-stress point while maintaining visual consistency with the surrounding roof.
Advantages: Balanced performance and aesthetics Best for: Medium-to-large chimneys on standard-pitch roofsAt Nest Exteriors, we build framed, shingled crickets on most residential projects, using ice and water shield over the entire cricket surface. For low-slope sections or chimneys wider than 42 inches, we switch to metal or hybrid construction.
Adding a Cricket During Roof Replacement
A roof replacement is the best time to add a cricket. The cost is dramatically lower than a retrofit because the chimney area is already exposed during tear-off. Here is how the process works:
Flashing Details That Make or Break a Cricket
The cricket itself is only half the equation. The flashing that connects the cricket to the chimney and the surrounding roof is where most failures occur.
Step Flashing
Individual L-shaped metal pieces woven into each shingle course where the cricket slope meets the chimney wall. Each piece overlaps the one below it, creating a shingle-like water barrier up the side of the chimney. We use 5-by-7-inch galvanized steel step flashing as our standard, with copper available for premium applications.
Counter Flashing
Metal strips mortared or sealed into the chimney masonry joints that overlap the step flashing. Counter flashing is the visible layer, it's what you see when you look at the chimney from the roof. It must overlap the step flashing by at least two inches to prevent wind-driven rain from entering behind the step.
Cricket Ridge Flashing
A continuous piece that runs along the cricket ridge from the chimney face back to the roof slope. This piece seals the peak of the cricket where the two angled surfaces meet. It's one of the most detail-sensitive pieces on the entire roof.
For a deeper look at flashing types and failure modes, see our roof flashing guide.
Inspecting an Existing Cricket
If your chimney already has a cricket, here is what to watch for between professional inspections:
From the ground with binoculars:- Shingles on the cricket surface that look curled, cracked, or discolored compared to surrounding shingles
- Visible gaps between the cricket and the chimney wall
- Debris piled up at the base of the cricket (suggests the cricket is undersized or poorly shaped)
- Metal flashing that appears bent, lifted, or rusted
- Water stains on the underside of the deck directly behind the chimney
- Soft or discolored decking around the chimney penetration
- Daylight visible between the chimney masonry and the surrounding framing (indicates flashing failure, not just cricket issues)
- Ceiling or wall stains near the chimney, especially after heavy rain
- Musty odors near the fireplace area
- Peeling paint on walls adjacent to the chimney
The Impact We See on Inspections Across Northern Virginia
We inspect hundreds of roofs per year across Fairfax, Loudoun, Prince William, and Arlington counties. The pattern behind chimneys is consistent:
Chimneys without crickets: Earlier flashing failure, debris-trapped moisture, deteriorated decking, and higher rates of active leaking. The problems compound over time because the pooling never stops. Chimneys with well-built crickets: Clean, dry decking. Flashing that reaches end-of-life with the rest of the roof rather than failing prematurely. Minimal debris accumulation. Fewer emergency leak calls.The difference isn't subtle. A cricket is one of the most impactful additions you can make during a roof replacement, especially on homes with wide masonry chimneys, which describes the majority of chimney-equipped homes across Northern Virginia.
DaVinci and Composite Options for Historic Properties
For homeowners with DaVinci composite slate or shake roofing, crickets are built the same way but finished with matching DaVinci tiles instead of asphalt shingles. The synthetic material's superior durability means the cricket surface will outlast a traditional shingled cricket by a significant margin.
If your home features a premium roofing material, make sure your contractor builds the cricket to the same standard as the rest of the roof. A high-end roof with a cheap cricket is a contradiction that will show up as a leak within a few years.
Cricket Sizing: Getting the Proportions Right
An undersized cricket is almost as bad as no cricket at all. The cricket ridge should extend from the chimney face back toward the roof slope at a pitch that creates meaningful water diversion, typically matching the slope of the surrounding roof.
For chimneys 30 to 36 inches wide, the cricket is a relatively small structure. For chimneys 42 to 48 inches wide, common on homes with double fireplaces or masonry chimneys serving multiple flues, the cricket becomes a significant roof feature that requires careful framing and flashing integration.
The general rule: the wider the chimney, the taller the cricket peak needs to be relative to the surrounding roof surface. An experienced crew sizes the cricket based on chimney width, roof pitch, and local precipitation patterns. In Northern Virginia, where thunderstorm intensity and annual rainfall exceed the national average, we err on the side of a slightly larger cricket rather than a smaller one.
Schedule a Chimney Assessment
If your home has a chimney and you aren't sure whether a cricket is present, or if you've been dealing with chimney-area leaks, a professional inspection is the fastest path to answers.
Nest Exteriors evaluates chimney conditions as part of every roof inspection. We document the cricket (or its absence), assess flashing integrity, photograph every detail, and provide a clear recommendation with cost estimates if work is needed.
Get a quick project estimate or book your free chimney and roof inspection. We serve homeowners throughout Fairfax County, Loudoun County, Prince William County, Arlington, and the greater Northern Virginia area.Written By
