Chimney Flashing & Skylight Repair in Connecticut

Why chimneys and skylights leak

Every chimney, skylight and vent is a hole through the roof’s water control layer, and the Building America Solution Center calls each one “a weak spot in the roof’s armor where water could leak into the building.” The Asphalt Roofing Manufacturers Association calls flashings the most vulnerable points, and the American Society of Home Inspectors (ASHI) says chimney flashings are more complex than other roof flashings and a common source of roof leaks.

Connecticut enforces the 2022 Connecticut State Building Code, which adopts the 2021 International Residential Code (IRC) without amending its flashing, skylight or chimney sections. The IRC requires flashing around roof openings and where roofs meet walls, and metal flashing must be corrosion resistant and at least 0.019 inch thick (R903.2.1). Our Connecticut roofing code guide and town roofing pages cover the statewide and local rules.

How chimney flashing is built

Step flashing and counterflashing

Chimney flashing has two parts. Because the roof deck can move relative to a masonry chimney, ASHI explains, base flashings are secured to the deck and counterflashings to the masonry, and the overlap lets the two move without opening the joint. Along the chimney’s sides, the base flashing is step flashing: short pieces nailed to the deck and worked in with the shingle courses. Step flashing is one part of chimney flashing, not an alternative to it. The IRC requires chimney flashing to follow the asphalt shingle manufacturer’s printed instructions (R905.2.8.4).

The counterflashing laps over the step flashing and stops short of the roof surface. In good work, its upper edge is set into a mortar joint that is then sealed (ASHI; InterNACHI). ASHI lists galvanized steel, galvalume, lead and copper among typical chimney flashing metals and says aluminum generally is not used because it is not compatible with masonry mortar.

Crickets and saddles

A cricket, or saddle, is a peak built on the ridge side of a chimney that, in ASHI’s words, deflects water and snow around it. The IRC: “A cricket or saddle shall be installed on the ridge side of any chimney or penetration more than 30 inches (762 mm) wide as measured perpendicular to the slope” (R903.2.2). The code’s masonry chimney section applies the rule to chimneys that do not reach the ridgeline, requires the cricket to be flashed and counterflashed like any roof-chimney joint, and sets its height from the chimney width (R1003.20):

Flashing leak or chimney problem?

Not every leak beside a chimney is a flashing leak. The Chimney Safety Institute of America (CSIA) says water causes more damage to masonry chimneys than fire, and its preventive advice covers four parts: a cap to keep out rainwater, a crown projecting two inches beyond all sides, the flashing, and the brick, which absorbs water “like a sponge.” Stallion Ridge repairs and replaces chimney flashing. For the chimney itself, CSIA recommends leaving annual inspections and preventive maintenance to a qualified chimney professional.

• From the ground: stay off the roof, as NRCA advises. ASHI checks for rust, loose flashing, flashing opened along its upper edge and missing pieces, and lists tar over metal flashing as a cause of rust.
• In the attic: look for stains or decay on the sheathing around the chimney or skylight (InterNACHI). In cooler climates, the Asphalt Roofing Manufacturers Association notes, stains can also be condensation from poor attic ventilation.

Skylights: mounting, flashing and code

Deck-mounted or curb-mounted

A curb-mounted skylight sits on framing that is built and waterproofed first; a deck-mounted skylight has its own curb and flange, sits lower, and is waterproofed directly to the roof deck, according to the Building America Solution Center. The Solution Center recommends curb-mounted units when a skylight is replaced without replacing the roof covering. On roofs pitched less than 3 in 12, the IRC requires a curb at least 4 inches above the roof unless the manufacturer’s installation instructions say otherwise (R308.6.8).

Flashing and code rules

The Solution Center’s steps work from the bottom up so each layer overlaps the one below: membrane at the sill, sides and head, then sill flashing, step flashing woven in with each shingle course, and head flashing. A unit skylight installed to R308.6 and flashed to its maker’s instructions may go without a cricket (R903.2.2).

Unit skylights must be tested by an independent laboratory and labeled to AAMA/WDMA/CSA 101/I.S.2/A440 (R308.6.9). All of Connecticut is in climate zone 5, where the energy code sets a maximum skylight U-factor of 0.55, and a replacement unit must meet that table (N1102.1.3, N1111.1.1.1). Connecticut’s permit exemptions cover roof repairs limited to 25 percent of the roof covering in a year but do not mention skylights, and VELUX notes that many municipalities require a permit to install one; ask the town building department.

Replace the skylight with the roof?

The Solution Center says reroofing is the time to inspect skylights: keep one that is in good shape, relatively new and performing well, and consider replacing one that is damaged, leaking or losing too much heat. VELUX recommends replacing skylights when the roof is updated, saying it lines up the skylight and roofing warranties. When a roof is replaced, rusted, damaged or deteriorated flashings must be replaced too (R908.5). A full roof replacement with Stallion Ridge starts around $650 per roofing square (100 square feet) and goes up depending on the roof.

Ice dams around chimneys and skylights

Ice dams form when the upper roof is above freezing and the lower edge is below, so snowmelt refreezes and backs up until the water finds openings in the roof covering, according to University of Minnesota Extension. Extension names chimneys as a source of attic heat when wood stoves and fireplaces are used often, and lists skylights among features that increase the risk. NRCA advises against breaking up ice dams yourself, since flashings and gutters can be damaged. The Building America Solution Center recommends air sealing the ceiling, insulating the attic and ventilating the roof.

Chimney flashing and skylights from Stallion Ridge Exteriors

Stallion Ridge Exteriors is based in Bethel, Connecticut, and has served all of Connecticut plus Westchester, Putnam and Dutchess Counties, New York, since 2022. We also offer roof and leak repair, roof replacement on shingle, metal, flat, slate, cedar shake and synthetic roofs, gutters, emergency tarping, roof cleaning and commercial roofing. Roof inspections are free, and we offer a 25-year workmanship warranty.

Common questions about chimney flashing and skylights

Sources: 2022 Connecticut State Building Code and the 2021 International Residential Code it adopts; U.S. Department of Energy Building America Solution Center; EPA; University of Minnesota Extension; NRCA; Asphalt Roofing Manufacturers Association; Chimney Safety Institute of America; American Society of Home Inspectors; InterNACHI; VELUX. Checked September 17, 2026.