Chimney flashing repair: cost, signs and code rules

Updated October 2, 2026 · Every figure checked twice against its source · How we verify

Chimney flashing repair costs $300 to $1,800 on average, according to HomeGuide, depending on the extent of damage, the flashing material, the chimney size and how easy the roof is to reach. HomeGuide says minor resealing may cost as little as $200, while complete flashing replacement on a large chimney can reach $1,800 or more. Fixr's figures run lower: $200 to $300 for a flashing repair and $300 to $800 to replace the flashing. HomeGuide says labor typically accounts for 60% to 70% of the total.

Chimney flashing repair cost

HomeGuide prices the job by chimney size because larger chimneys take more flashing material and more labor. The chimney's own material matters too: contractors must cut into masonry to install new flashing properly, and HomeGuide says natural stone is harder and slower to work with than soft manufactured veneer, with brick in the middle. It says metal or prefabricated chimneys typically cost less to reflash than masonry ones.

Labor is most of the price. HomeGuide says professional masons or chimney sweeps charge $50 to $125 an hour on average, and some charge a flat rate instead. Fixr puts chimney repair labor at $50 to $150 an hour and says scaffolding, when the chimney needs it, can add $50 to $200. Roof height, pitch and access also move the price: HomeGuide says multi-story homes and steep roofs need extra safety equipment, which adds labor time.

Plan for the extras HomeGuide lists: a chimney inspection at $100 to $250, a roof inspection at $100 to $400, and sealing a chimney at $150 to $400, or up to $850 with waterproofing. Local building codes might require permits and inspections, it says, and historic districts may add requirements.

Cost to replace chimney flashing

Fixr puts chimney flashing replacement at $300 to $800 and says that if the damage is too extensive to be patched, the flashing must be replaced. HomeGuide draws the same line: small cracks or lifted edges can often be fixed with sealant or patching, but extensive damage that involves rusted metal, missing sections or water infiltration beneath shingles may call for full replacement. HomeGuide's top figure for a complete replacement on a large chimney is $1,800 or more.

HomeGuide says galvanized steel's zinc coating protects against rust but is not ideal for coastal areas, and copper costs the most but needs minimal maintenance. HomeGuide describes chimney flashing as a system of overlapping components rather than a single piece of metal: step flashing (L-shaped sheets that alternate with the shingles along the sides), counter flashing installed over the step flashing with its top edge embedded in the mortar joints, and base flashing that seals the lower joint where the chimney face meets the roof.

Why is my chimney leaking?

Fixr says chimney leaks are most often caused by damaged flashing, though cracks in the mortar or the bricks themselves can also let water in. Its chimney repair guide says leaks usually happen where the roof meets the chimney, when cracks or holes appear or the flashing wears away, and that the repair means fixing or replacing the flashing and possibly resealing the damaged area.

Fixr's two guides price this differently. Its chimney repair guide puts a leaky chimney fix at $150 to $500. Its roof leak guide, updated January 27, 2026, puts repairing a leaking chimney at $200 to $3,500, with minor work such as replacing a chimney cap at the low end and major work on damaged bricks, mortar or flashing at the high end.

The Chimney Safety Institute of America (CSIA) says water causes more damage to masonry chimneys than fire, and that flashing is the seal between the roofing material and the chimney that keeps rain water from running down the chimney into living spaces, where it can damage ceilings and walls and cause rafters and joists to rot. CSIA calls water damage to chimneys usually a slow process that is easily ignored until problems have become quite serious.

Signs you need chimney flashing repair

HomeGuide lists these warning signs:

• Water stains on ceilings or walls near the chimney
• Damp spots in the attic around the chimney base
• Rust or corrosion visible on metal flashing
• Gaps or separation between the flashing and the chimney or roof
• Loose or missing flashing sections
• Cracked or deteriorating sealant or caulking
• A mold or mildew smell near the fireplace
• Damaged or lifted shingles around the chimney base
• Interior leaks during or after rainfall
• Daylight visible through gaps in the flashing

HomeGuide lists a chimney inspection, at $100 to $250, among the extra costs of a flashing job.

What the building code requires for chimney flashing

Where the 2021 International Residential Code (IRC) is adopted, these sections apply to the flashing around a chimney:

A cricket or saddle goes on the ridge side of the chimney (R903.2.2). The code's two cricket sections word the 30-inch trigger differently, as shown above. The Asphalt Roofing Manufacturers Association (ARMA) goes further than the code: the 2014 edition of its residential manual strongly recommends a cricket on any chimney 24 inches or greater in width, and notes that the IRC, as of that edition, requires one on any chimney greater than 30 inches wide.

ARMA also explains why chimney flashing comes in two layers. Because the chimney and the roof can move differently, the manual calls for apron flashings secured to the roof deck and counter flashings secured to the masonry; if movement occurs, the counter flashing slides over the apron flashing without affecting water runoff.

How to repair chimney flashing

The first decision is patch or replace. HomeGuide says small cracks or lifted edges can often be fixed with sealant or patching, while rusted metal, missing sections or water beneath the shingles may mean full replacement. Fixr says superficial damage can be patched to avoid leaks.

New flashing on an asphalt shingle roof follows the shingle maker's instructions, which is what R905.2.8.4 requires. GAF's Timberline HDZ installation instructions cover these points for chimney flashing and crickets. The first three are given in order:

1. Underlayment around the chimney. Cover the deck around the chimney, and over wood crickets, with GAF Roof Deck Protection, but do not run it up the sides of the chimney (GAF).
2. Leak barrier up the sides. Install leak barrier over the roof deck protection and up the sides of the chimney at least 5 inches (GAF).
3. Cricket flashing. Install shop-fabricated metal cricket flashings after the underlayments are in. GAF says crickets should extend at least 6 inches up the back of the chimney and at least 12 inches up the roof deck, and the shingles are sealed to the metal flange with asphalt plastic cement. A large wooden cricket is treated like a separate roof, with its own valleys, shingles, hip and ridge shingles and step flashing.

Two more points appear as callouts on GAF's chimney drawing, without a step order:

• Step flashing: use one-piece, non-corroding metal step flashing for each course, and seal the overlying shingles to it with asphalt plastic cement.
• Counter flashing: extend non-corroding metal counter flashing over the base flashing.

Fixr does not recommend that homeowners take a DIY approach to chimney repair, saying it can be very dangerous to get on the roof to repair a chimney without the necessary tools and experience. Crown, cap, liner and repointing prices are on our chimney repair cost guide.

Who replaces chimney flashing?

Both professional roofers and certified chimney sweeps can replace chimney flashing, HomeGuide says. It describes roofers as experienced with shingle removal, roof penetrations and watertight seals, and chimney sweeps as specialists in chimney structure and masonry work. Its advice is to choose a contractor licensed and insured for both roofing and chimney work, and to ask about their experience with flashing repairs.

HomeGuide suggests getting estimates from at least three companies and asking each one:

• Will you provide a detailed written estimate breaking down materials and labor?
• What type of flashing material do you recommend for my chimney, and why?
• Do you need to remove any roof shingles, and are those included in the estimate?
• What warranty do you offer on materials and workmanship?
• Will you handle all necessary permits and inspections?

For flue cleaning, see our chimney sweep guide. To get a price for your chimney, use the form below and we will send your request to a company that serves your ZIP code.

Sources

1. HomeGuide, "How much does chimney flashing repair cost?", February 10, 2026: homeguide.com
2. Fixr, chimney repair cost, updated January 31, 2025: fixr.com
3. Fixr, cost to repair roof leaks, updated January 27, 2026: fixr.com
4. International Code Council, 2021 International Residential Code, chapter 9, roof assemblies (R903.2, R905.2.8, R908): codes.iccsafe.org
5. International Code Council, 2021 International Residential Code, chapter 10, chimneys and fireplaces (R1003.20): codes.iccsafe.org
6. Chimney Safety Institute of America, "Four Low-Cost Recommendations to Prevent Major Water Damage", June 11, 2010: csia.org
7. Asphalt Roofing Manufacturers Association, Residential Asphalt Roofing Manual, 2014 edition, chapter 10, flashing: asphaltroofing.org
8. GAF, Timberline HDZ installation instructions, 2023: gaf.com

Fixr's chimney repair guide read September 25, 2026; 2021 IRC chapter 10 read September 30, 2026; all other sources read October 2, 2026.