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Updated June 2026

Best Flat & Low-Slope Roofing Contractors in Seattle

Compare services, check credentials, and contact a roofing company directly.

How we choose

5 results

Compare contractors (5)

Quick Comparison

Rank Company Specialty Experience BBB Website
1 Pinnacle Roofing Professionals Roofing, Solar & Chimneys Local Listed Visit
2 Three Tree Roofing Residential & Commercial 20+ Yrs Listed Visit
3 Guardian Roofing, Gutters & Insulation Residential & Commercial Roofing Since 2005 Listed Visit
4 Chase Construction North West Residential & Commercial Roofing Since 2002 A+ Accredited Visit
5 The Seattle Roofing Company Residential & Commercial Local A- Accredited Visit

Detailed Reviews

#2

Three Tree Roofing

Residential & Commercial
Experience20+ Years
BBB StatusListed
SpecialtyResidential & Commercial
Service AreaSeattle & Puget Sound
Services and company details

Three Tree Roofing is a family-run, full-service roofing company with more than 20 years of experience serving Seattle and the greater Puget Sound. It promotes its standing as a top CertainTeed contractor in Washington, having earned a CertainTeed SureStart Plus award. The company installs composite shingle, metal, flat, cedar shake, and synthetic roofs, plus solar shingle systems, for both residential and commercial clients, and also handles gutters. It operates under Washington registration THREETR832OL.

Roof Replacement Roof Repair Metal Roofing Flat Roofing Cedar Shake Roofing Solar Roofing Gutters
#3

Guardian Roofing, Gutters & Insulation

Residential & Commercial Roofing
ExperienceSince 2005 (20+ Years)
BBB StatusListed
SpecialtyResidential & Commercial Roofing
Service AreaSeattle & Puget Sound
Services and company details

Founded in 2005, Guardian Roofing, Gutters & Insulation serves the Seattle metro and broader Pacific Northwest from offices including Auburn and Everett. It works across asphalt shingle, metal, cedar shake, flat, and tile roofs and maintains a dedicated commercial division offering low-slope PVC and TPO flat-roof systems. Additional services span roof inspections, storm and wind damage repair, skylights, gutters and gutter guards, attic insulation, and HOA/property-management programs. It serves Seattle neighborhoods including Ballard, Capitol Hill, and West Seattle.

Roof Replacement Roof Repair Flat Roofing Commercial Roofing Storm Damage Gutters Attic Insulation Skylights
#4

Chase Construction North West

Residential & Commercial Roofing
ExperienceSince 2002 (20+ Years)
BBB StatusA+ Accredited
SpecialtyResidential & Commercial Roofing
Service AreaSeattle & South Puget Sound
Services and company details

Chase Construction North West, established in 2002 and now second-generation family-owned, serves Seattle and the South Puget Sound from its Edgewood office across King, Pierce, and Thurston counties. It is a GAF Master Elite contractor and works on both steep-slope systems (asphalt, composite, metal, cedar shake) and low-slope commercial roofs, including TPO, PVC, and silicone restoration coatings. Additional services include roof inspections, emergency repair, attic insulation, and siding. The BBB lists Chase Construction North West as an Accredited Business with an A+ rating, accredited since 2012. It holds Washington registration CHASECN981NN.

Roof Replacement Roof Repair Flat Roofing Commercial Roofing Metal Roofing Roof Coatings Attic Insulation
#5

The Seattle Roofing Company

Residential & Commercial
ExperienceEstablished local roofer
BBB StatusA- Accredited
SpecialtyResidential & Commercial
Service AreaSeattle & Puget Sound
Services and company details

The Seattle Roofing Company is a newer, locally focused firm whose ownership cites 20+ years of construction experience. It is a GAF Master Elite Certified Contractor and IKO ROOFPRO Advantage Certified, offering roof replacement and repair, inspections, storm-damage work, and commercial TPO and flat-roof systems with a stated $250,000 workmanship guarantee and 24/7 emergency service. The BBB lists it as an Accredited Business with an A- rating (accredited since 2024); it holds Washington registration SEATTSR761Q5.

Roof Replacement Roof Repair Storm Damage Roof Inspection Commercial Roofing Flat Roofing Emergency Roof Repair

Seattle's Persistent Rain Climate and the Case for Flat-Roof Expertise

Your flat roof has moss or biological growth reducing membrane performance

Moss and lichen growth on Seattle flat roofs is not cosmetic — moss rhizoids physically penetrate membrane surfaces over time and accelerate UV-induced degradation. A flat-roof specialist who operates year-round in the Puget Sound market will include biological growth treatment as part of any maintenance scope, and will specify membranes with biocide-infused surfaces or coatings that resist re-colonization.

You're considering a green roof or rooftop garden on your Seattle building

Seattle's land-use incentives and LEED certification pathways make green roofs financially meaningful on many commercial projects. Green roof assemblies require a waterproofing membrane rated for root barrier compatibility and typically demand structural engineering review for the additional dead load. A flat-roof contractor with green-roof experience in Seattle will coordinate the waterproofing scope with landscape architects and structural engineers rather than treating the roof as an isolated trade.

Your building's flat roof drains slowly or shows persistent ponding

Seattle's low-angle rainfall — often horizontal in winter wind events — means that drainage design on flat roofs must accommodate both vertical precipitation and wind-driven water at vertical surfaces. Chronic ponding in Seattle indicates either blocked or undersized drains or inadequate slope in the insulation assembly. A flat-roof specialist who regularly works in western Washington will recognize these failure patterns and provide a drainage correction that accounts for the local precipitation character.

Frequently Asked Questions

How many flat & low-slope roofing contractors are in Seattle?

Our directory lists 5 independently verified flat & low-slope roofing contractors serving Seattle, Washington, ranked by experience, certifications and reputation. Pinnacle Roofing Professionals is ranked #1.

How do I choose a flat & low-slope roofer in Seattle?

Confirm licensing and insurance for Washington, ask for flat & low-slope project references in Seattle, get multiple written quotes, and check each contractor's BBB standing. Every company listed here has been independently researched.

What flat-roof membrane is best suited for Seattle's rainy climate?

Fully adhered TPO or PVC membranes perform well in Seattle because their heat-welded seams create a truly monolithic barrier without the fastener penetrations that create water pathways in mechanically attached systems. Modified bitumen remains reliable on complex roofs with many penetrations. The critical specification detail in Seattle's climate is that all laps and flashings be fully bonded and that drainage is designed for chronic slow-flow rather than intermittent high-intensity events.

Does Seattle's climate make flat roofs inherently less durable than pitched roofs?

A properly designed and installed flat roof in Seattle is not inherently less durable than a pitched system — many Seattle commercial buildings with flat roofs have maintained weathertight envelopes for decades. The risk in Seattle is that a flat roof specified without adequate attention to drainage slope, membrane continuity, and biological growth resistance will fail faster than expected. The quality of design and installation matters more than the roof's pitch in this climate.

Are there Seattle permit requirements for flat-roof replacement projects?

The City of Seattle requires a construction permit for re-roofing projects that meet certain thresholds — generally, full replacements on commercial buildings and multifamily residential structures. Seattle's permit system also requires that roofing work comply with the Washington State Energy Code's thermal requirements, which means insulation upgrades may be required when existing insulation falls below current minimums. A flat-roof contractor familiar with Seattle's permit office processes will include permitting in the project schedule.