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Chimney Waterproofing

Chimney Waterproofing in Seattle, WA

Seattle's 152 rain days per year make chimney waterproofing essential — not optional. We apply professional-grade, vapor-permeable sealants that keep rainwater out while allowing trapped moisture to escape, preventing the spalling, cracking, and structural damage that destroy unprotected chimneys in the Pacific Northwest.

Licensed & Insured
4.9/5 — 180+ Reviews
Same-Day Available

How It Works

1

Inspect & Prep

We inspect the entire chimney for existing damage — cracks, spalling, failed mortar. Any repairs are completed first. The masonry surface is cleaned to ensure proper sealant adhesion.

2

Apply Sealant

We apply professional-grade, vapor-permeable waterproofing in multiple coats. The chimney crown is sealed with a flexible crown coat that bridges hairline cracks and prevents water entry from the top.

3

Verify & Warrant

We verify complete coverage, document the work with photos, and provide a written warranty. You'll receive a recommended re-application schedule based on your chimney's exposure.

Signs Your Chimney Needs Waterproofing

  • ! White staining (efflorescence) on chimney bricks
  • ! Brick faces flaking or crumbling (spalling)
  • ! Mortar joints receding or turning sandy
  • ! Dark water stains on chimney exterior after rain
  • ! Damp or musty smell near the fireplace
  • ! Water stains on ceiling or walls near the chimney
  • ! Green moss or algae growing on chimney bricks
  • ! Chimney crown has visible cracks or gaps

Pricing Guide

Standard

$300 – $500

Masonry sealant application, one chimney, 5-year protection

Most Common

With Crown Seal

$500 – $800

Waterproofing + crown repair & seal, 7-year protection

Full System

$800+

Waterproofing, crown, flashing check, 10-year full protection

Prices are estimates for the Seattle metro area. Exact pricing depends on chimney size, surface area, and condition. We provide free, detailed quotes before any work begins.

Why Choose Us

Vapor-permeable sealants (ChimneySaver & equivalent products)
Prevents water penetration without trapping moisture inside
Stops spalling, efflorescence, and freeze-thaw damage
Chimney crown sealing and crack repair included
Full chimney masonry waterproofing — brick and mortar
Protection lasts 5-10 years per application
Transparent finish — no change to brick appearance
Applied to the entire chimney exterior above the roofline
Pre-treatment cleaning and masonry inspection included
Prevents mold growth inside chimney and walls
Extends chimney lifespan by decades
Written warranty on all waterproofing work

What Customers Say

“Seattle Chimney Pros saved us from what could have been a disaster. They found a major crack in our flue liner during a routine inspection. Professional, honest, and fairly priced!”

Sarah M.
Capitol Hill, Seattle
Chimney Inspection

“We've used three different chimney companies over the years. Seattle Chimney Pros is by far the best. They showed up on time, explained everything, and the creosote removal was thorough.”

David & Lisa R.
Ballard, Seattle
Creosote Removal

“Had an emergency leak during a rainstorm. Called Seattle Chimney Pros and they were at my house within 2 hours. Fixed the crown and flashing the next day. The real deal!”

James T.
Bellevue, WA
Chimney Repair

“Our gas fireplace hadn't been serviced in years. They did a full maintenance check, replaced a faulty valve, and now it runs perfectly. Fair pricing with no upselling.”

Michelle K.
Fremont, Seattle
Gas Fireplace

“The team rebuilt the top section of our 80-year-old chimney. The brickwork is flawless — you can't even tell which part is new. True craftsmen.”

Robert P.
Queen Anne, Seattle
Chimney Repair

“I was quoted $4,000 by another company. Seattle Chimney Pros gave an honest assessment and fixed the issue for under $1,200. They've earned a customer for life.”

Angela W.
Kirkland, WA
Chimney Repair

“We had our chimney waterproofed before the rainy season. No leaks all winter — first time in 10 years. Wish we'd found them sooner. Highly recommend!”

Tom & Karen B.
West Seattle
Chimney Waterproofing

“Fast, clean, and professional. They installed a new chimney cap and inspected the crown in one visit. Everything explained clearly with photos. 5 stars.”

Linda H.
Magnolia, Seattle
Chimney Cap Installation

“Our old clay liner was crumbling. They installed a stainless steel liner and the difference in draft is incredible. Job done right the first time.”

Mark S.
Redmond, WA
Chimney Relining

Frequently Asked Questions

How much does chimney waterproofing cost in Seattle? +
Standard chimney waterproofing in Seattle costs $300-$500 for a single chimney. Adding a crown seal brings the cost to $500-$800. A full moisture protection system (waterproofing, crown seal, and flashing check) runs $800-$1,200. Exact pricing depends on chimney size and condition. We provide free estimates.
Is chimney waterproofing really necessary in Seattle? +
In Seattle, waterproofing is one of the most important chimney maintenance services you can invest in. With 152 rain days and 37 inches of annual rainfall, water is constantly penetrating your chimney's porous brick and mortar. Without waterproofing, you'll see spalling, efflorescence, mortar deterioration, and eventually structural damage that costs thousands to repair.
What is the difference between waterproofing and painting a chimney? +
Paint and standard sealers create an airtight barrier that traps moisture inside the brick — actually accelerating damage from the inside out. Professional chimney waterproofing uses vapor-permeable sealants that repel liquid water from outside while allowing water vapor trapped inside the masonry to escape. This breathable protection is critical in Seattle's constantly damp climate.
How long does chimney waterproofing last? +
Professional chimney waterproofing lasts 5-10 years depending on the product used and the chimney's exposure to weather. South and west-facing chimneys in Seattle may need re-application sooner due to greater rain and UV exposure. We provide a recommended re-application schedule with every treatment.
Can you waterproof a chimney that already has damage? +
We always inspect for existing damage before waterproofing. If we find spalling, cracked mortar, or crown damage, those repairs must be completed first. Applying waterproofing over damaged masonry traps water inside and accelerates deterioration. Once repairs are done, waterproofing prevents future damage from occurring.
Will chimney waterproofing change the look of my bricks? +
No. The vapor-permeable sealants we use are completely transparent and do not change the color, texture, or appearance of your brickwork. Your chimney will look exactly the same — just protected from moisture penetration.
What is efflorescence and does waterproofing stop it? +
Efflorescence is the white, chalky staining that appears on brick when water migrates through the masonry, dissolves mineral salts, and deposits them on the surface as it evaporates. Waterproofing stops the water penetration that causes efflorescence. If existing staining is present, we clean it before applying the sealant.
Should I get a chimney cap and waterproofing together? +
Yes — they complement each other perfectly. A chimney cap prevents rain from entering the flue from above, while waterproofing prevents rain from penetrating the brickwork from the sides. Together, they form a complete moisture defense system. We offer package pricing when both services are done at the same visit.

Learn More

Brick and mortar are porous materials. In a city like Seattle — where annual rainfall averages 37 inches spread across 152 rain days — water is constantly penetrating your chimney's masonry. Once inside, that moisture wreaks havoc. During cold snaps, trapped water freezes and expands, cracking mortar joints and popping the faces off bricks in a process called spalling. In warmer weather, the moisture migrates inward, carrying dissolved salts to the surface as ugly white staining known as efflorescence.
Over time, this relentless moisture cycle deteriorates even the strongest chimneys. Mortar joints recede and crumble. Bricks loosen. The chimney crown develops cracks that let even more water in. Eventually, what started as simple water absorption becomes a structural problem requiring thousands of dollars in masonry repair or a complete chimney rebuild. The solution? Professional chimney waterproofing — applied before the damage cycle begins, or immediately after repairs are completed.
At Seattle Chimney Pros, we use vapor-permeable waterproofing sealants specifically designed for chimney masonry. Unlike paint or standard sealers that trap moisture inside the brick (actually accelerating damage), our products form a breathable barrier that repels liquid water from the outside while allowing water vapor already inside the masonry to escape. This is critical in Seattle's climate, where chimneys rarely get a chance to fully dry out between rain events.
Our waterproofing process begins with a thorough chimney inspection to identify any existing damage. If we find cracked mortar, spalling bricks, or crown deterioration, we recommend completing chimney repairs first — sealing over damaged masonry only locks the problems in. Once the chimney is sound, we clean the surface, apply the waterproofing agent in multiple coats, and seal the chimney crown with a flexible, waterproof crown coat that bridges hairline cracks.
A professional chimney waterproofing treatment lasts 5-10 years in Seattle conditions and is the most cost-effective preventive maintenance you can invest in. For complete rain protection, we recommend pairing waterproofing with a quality chimney cap installation — the cap stops water from entering the flue from above, while the sealant stops it from penetrating the brickwork from the sides. Together, they form a complete moisture defense system.

Related Services

Chimney Repair

Waterproofing works best on sound masonry. If your chimney has existing damage, our masons repair it first — then we seal it for long-term protection.

Learn more

Chimney Cap Installation

Complete your moisture defense system with a professional chimney cap. Stops rain from entering the flue while waterproofing protects the brickwork.

Learn more

Chimney Inspection

Not sure if your chimney needs waterproofing? A CSIA-certified inspection reveals moisture damage, mortar condition, and crown integrity.

Learn more

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Get Free Estimate(253) 429-8006