Chimney Waterproofing Cost
The treatment includes two coats of breathable masonry sealer on the exterior brick and mortar above the roof. Cleaning, masonry repairs and any required access equipment are priced separately.
Waterproofing reduces water absorption through sound masonry. It does not repair cracks or stop leaks through a damaged crown, missing cap or defective flashing.
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How Much Does Chimney Waterproofing Cost?
Brown Chimney prices waterproofing by the size of the chimney above the roof. The treatment covers the exposed brick and mortar within the agreed scope.
| Chimney size | Size guide | Waterproofing price |
|---|---|---|
| Small | Single flue, up to 5 feet above the roof | $800 |
| Medium | Up to 8 feet above the roof, or two flues | $1,500 |
| Large | More than 8 feet above the roof, or three or more flues | $2,750 |
Height and flue count are assessed together. If your chimney falls across different size descriptions, we confirm the applicable category on site.
The price covers application to clean, dry masonry. Your total may also include:
- Exterior cleaning if dirt, moss or surface contamination must be removed.
- Mortar joint or brick repairs needed before treatment.
- Separate crown or flashing repairs if those components are allowing water in.
- Lift or scaffolding equipment when safe ladder access is not possible.
Is Chimney Cleaning Included?
Exterior chimney power washing is a separate service, recommended when preparation requires it. Its listed prices are $500 for a small chimney, $900 for a medium chimney and $1,300 for a large chimney. The cleaning method must suit the condition of the masonry.
For example, a small chimney requiring both power washing and waterproofing would total $1,300 before any repairs or additional access costs: $500 for washing plus $800 for treatment.
Exterior washing is different from sweeping the inside of the chimney. It also does not guarantee removal of deep staining, rust marks or old paint.
Fireplace use does not determine weather exposure. Read whether an infrequently used chimney still needs waterproofing.
What drives the price
What Affects Your Chimney Waterproofing Estimate?
1. Chimney Size Above the Roof
The height and number of flues help establish the size category. A taller or wider chimney has more exposed masonry to treat. The final category is confirmed after assessing the chimney on site.
2. Surface Cleaning and Preparation
The sealer needs a clean, dry surface. Moss, dirt, existing coatings and deteriorating material can affect preparation. Where exterior washing is appropriate, it is quoted separately, and the masonry must dry before treatment.
3. Brick and Mortar Condition
Waterproofing cannot replace missing mortar or restore damaged bricks. Open joints and loose material need assessment before a sealer is applied. If the mortar joints are deteriorating, chimney tuckpointing and mortar joint repair may be needed first. New mortar must cure sufficiently for the selected treatment.
4. Safe Roof Access
Roof pitch, chimney position and working height affect access. If the work requires a lift or scaffolding, that equipment is listed separately in the estimate. A larger chimney does not automatically mean equipment is needed; access is assessed for the specific property.
What you get
What Is Included in Chimney Waterproofing?
Our chimney waterproofing service applies a breathable masonry treatment to exterior brick and mortar above the roof. The purpose is to reduce rainwater absorption while allowing moisture vapor to escape.
Treatment is applied to suitable, clean and dry masonry. If cleaning or repairs are necessary, those items are identified separately so you can see the preparation cost alongside the waterproofing price.
Waterproofing does not include repointing, brick replacement, crown reconstruction, flashing replacement or interior chimney repairs. It also does not guarantee that an existing leak will stop if water is entering through another component.
The agreed waterproofing scope includes:
Confirmation of the chimney size category.
Identification of the exterior masonry to be treated.
A check that the surface is ready for application.
Breathable masonry sealer.
Two-coat application.
Coverage of the above-roof brick and mortar within the agreed scope.
A 1-year workmanship warranty, subject to its terms.
For an explanation of how different defects contribute to moisture problems, read how chimney leaks start from the inside out.
Step 1
Get your price in 30 seconds
Step 2
Get a Waterproofing Estimate for Your Chimney
Find out whether your chimney needs waterproofing alone or preparation and repairs first. Brown Chimney will confirm the size category, assess access and identify separate work before finalizing the scope.
Application depends on suitable weather and dry masonry. If rain or freezing conditions prevent proper treatment, the work will need to be rescheduled.
Planning additional chimney work? Explore our chimney cost calculators.
Service area
We Serve These Cities and a 20-Mile Radius Around Each
- Ann Arbor,
- Troy,
- Northville,
- Rochester Hills,
- Brighton,
- Farmington Hills,
- Novi,
- Birmingham,
- Bloomfield Hills,
- West Bloomfield
- Burlington,
- Wellesley
- Southlake,
- Dallas
- Carmel
- Providence
- Matawan
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Chimney Waterproofing FAQs
Water entering at the roof-to-chimney connection may require chimney flashing and leak repair. The source should be assessed before choosing a treatment.
The Chimney Safety Institute of America’s guidance on preventing water damage identifies waterproofing, crown repairs, flashing repairs and chimney caps as separate measures.
If crown work is needed, use our chimney crown repair or rebuild cost calculator to explore that separate part of the project. The appropriate repair must be established before relying on waterproofing for protection.
A film-forming coating that traps moisture is not interchangeable with this treatment. Existing paint or coatings need assessment because they can affect whether the proposed product is suitable and what preparation is required.
This interval is a maintenance recommendation, not a guarantee that every application will perform for a fixed number of years.
Cleaning or repointing may therefore require a separate preparation stage before treatment. Rain or freezing conditions can also delay application. The schedule should follow the selected product’s requirements rather than a fixed same-day promise.
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