Metal Coping Seattle — Custom-Fabricated. Installed Right.
Parapet caps, kick-out flashing, head flashing, drip edges. We fabricate on-site from prefinished galvanized steel, aluminum, copper, or zinc — hemmed drip edges, sealed seams, water-tight details that keep your wall dry for decades.
GP General Corp fabricates and installs custom metal coping and parapet caps across Seattle, the Eastside, and Snohomish County — break-formed in-house, cleated and sealed to stop water at the top of the wall. WA license GPGENGC830KD, MBAKS member, rated 5.0 on Google. Real installed rates on our pricing page; free written quote after an on-site assessment.
By Paul Gubenya — Owner, James Hardie Certified Installer · WA License #GPGENGC830KD · MBAKS Member · Rated 5.0 on Google · (425) 344-9635
What Homeowners Say
Real reviews from our Google profile — unedited, from real projects.
“We recently had Paul with GP General repair a damaged corner protector and sidings. His estimate was reasonable, his availability was timely, and his job was excellent. Our home hadn’t been re-painted in a while and the paint had considerably faded, yet he was able to match the color perfectly. Now we know who to turn to when in need of another repair work.”
“GP General replaced LP siding on our garage. Paul was very thorough when he came out to do the estimate; he listened to my concerns and was able to work out solutions on the spot. His crew did a great job and were very courteous. They also were careful about cleaning up (I didn’t find any nails!). Really happy with the job and can recommend GP General.”
“I highly recommend GP General Corp for siding replacement. We recently had our wood siding replaced with James Hardie lap siding, and Paul and his team did an excellent job.”
Why Most Metal Coping Fails
Most coping installations we assess have a metal cap and nothing underneath it. That’s not a coping system — that’s sheet metal nailed to the top of a wall. Correct installation requires three distinct components. Most contractors only install one.
Recent metal coping projects:
- Mercer Island reside with metal coping on every parapet →
- Seattle metal coping replacement — failed cedar to 24g AEP standing-seam + new fireplace cap →
- Bellevue modern new construction with custom metal coping on every parapet →
Ready to talk about your project?
Free walk-through with Paul. No-pressure quote. Honest assessment of what your home needs.
Metal Coping Installation Cost Seattle
AEP 24-gauge galvanized steel coping installed with metal undercap and high-temp flashing tape runs $30–$45 per linear foot in the Seattle area. A typical residential flat-roof addition with 60 LF of parapet would run $1,800–$2,700. A commercial building with 200 LF might run $8,000–$12,000 depending on profile and access. Key cost drivers: wall width, profile complexity, substrate condition, and scaffolding requirements.
Installed Price Range
What Is Metal Coping — and When Does a Seattle Building Need It?
Metal coping is a custom-fabricated metal cap installed along the horizontal top edge of a parapet wall, a flat-roof termination, a low-slope roof edge, or the top of exterior architectural details like window bucks and stone wainscots. Its single job is to shed water off horizontal surfaces that would otherwise pool rain and let moisture migrate down into the wall assembly behind the siding.
In Seattle, every flat-roof and low-slope structure — mid-century modern homes, contemporary remodels, mixed-use buildings, and commercial roofs — needs some form of coping at the top of exposed walls. Built-up tar or membrane coping is the short-term solution. Custom-fabricated metal coping is the 30–40-year answer. If your building has parapet walls that are older than about 10 years without metal caps, they’re almost certainly absorbing more water than you realize.
You likely need new or upgraded metal coping if…
- You see standing water or dark staining along the top of your parapet after rain
- Your existing cap shows exposed fastener heads (these rust and leak within 7–10 years)
- Caulked or sealed end joints have cracked or pulled away from the metal
- You’re planning new siding or a rainscreen system install and the old coping is approaching end of life
- Interior drywall near the top of an exterior wall shows discoloration or soft spots
- You’re building a new flat-roof or low-slope home and need coping spec’d from day one
Not sure where to start?
We’ll come out, look at your siding, and give you a straight answer — even if the answer is “you don’t need us yet.”
Metal Options for Coping — Which Material Fits Your Project
Four metals cover 95% of Seattle-area coping jobs. Choice depends on elevation, budget, architectural context, and whether the wall is exposed to salt air.
| Material | Price ($ / lf) | Service Life | Best For |
|---|---|---|---|
| Prefinished Galvanized Steel | $28–$38 | 30–40 yrs | 80% of residential + commercial Seattle jobs |
| Aluminum | $32–$45 | 40–50 yrs | Coastal, salt-air exposure (Mukilteo, Edmonds waterfront) |
| Copper | $95–$145 | 80–100+ yrs | Premium estates, historic restoration, Artisan-style projects |
| Zinc | $75–$115 | 80–100+ yrs | Modern architecture, muted patina look |
24-gauge galvanized steel with factory-applied Kynar 500 finish (50-year color warranty). Our default for 80% of residential and commercial Seattle jobs — best balance of durability, cost, and PNW corrosion resistance inland. Available in 20+ architectural colors.
.040 or .050 aluminum with Kynar 500 finish. Zero rust risk — spec on waterfront and salt-exposed elevations. Lighter than steel (easier fabrication on complex corners), cuts cleanly for custom profiles. Common on Edmonds, Mukilteo, Mercer Island, and Anacortes projects.
For maximum durability in harsh environments. 316 on saltwater-facing coastal installs. Used when the project demands 50+ year service with minimal maintenance. Can be finished with brushed, #4 mill, or Kynar-coated for architectural matching.
Specified on heritage restorations, high-end custom homes, and architecturally significant projects. Develops natural patina over 5–7 years. 80+ year service life. We source 16 oz sheet copper from domestic mills. Beautiful on Capitol Hill historic homes and West Bellevue custom builds.
Our Metal Coping Installation Process
Every coping job follows the same six-step rigor we use on full siding installations — with metal-coping-specific detailing.
- On-site measurement & parapet inspection. We laser-measure every linear foot of coping needed, confirm parapet wall squareness and plumb, and identify any rot or deterioration in the existing substrate. You get a written scope and a fixed-price quote with no surprises on demo day.
- Permit filing & submittal. City of Seattle, Bellevue, Everett, or the relevant jurisdiction — we file the building permit and coordinate HOA architectural review when required (common on Eastside custom homes).
- Substrate prep. Old coping removed, parapet top inspected for rot and structural damage. Any compromised plywood substrate replaced. Continuous bond-break and self-adhered flashing membrane installed over the prepped top.
- Custom fabrication. Coping sections custom-fabricated in our shop to the measured lengths, with accurate corner miters, factory-formed hems at the drip edge, and machine-broken end caps. Not field-cut from stock lengths — fabricated to your exact geometry.
- Concealed-cleat install. Continuous metal cleat mechanically fastened to the parapet substrate. Coping sections hooked over the cleat and locked in place — no exposed fasteners on the face where water would find them. Corners and end caps are mechanically locked and soldered (copper/stainless) or sealed with rated elastomeric sealant behind the hem.
- Final walk-through. We walk the property with you at the end of the job to make sure everything looks great and you’re happy with the final result. It’s a 20-point walk: caulk lines, paint touchups, downspout reattachment, gutter reset, and site cleanup.
Metal Coping FAQ
What is metal coping and where is it installed?
How long does metal coping last compared to built-up or membrane coping?
What metals do you use for coping in Seattle?
Can you install metal coping on an existing building without removing the roofing?
Why do metal copings fail on Seattle homes?
How much does metal coping cost per linear foot in the Seattle area?
Do I need metal coping if I already have a metal siding system on my parapet?
Do you install metal coping on residential window bucks and wainscot tops?
What’s the difference between metal coping and traditional wood-and-membrane parapet caps?
Will metal coping leak at the joints over time?
Can metal coping be installed in winter in Seattle?
Metal Coping — Across Seattle Neighborhoods
We work in every Seattle neighborhood. Each area has its own housing stock, climate exposure, and common siding challenges.
Parapet or Roof Edge Needs Coping?
No sales pressure. We assess what you have and quote exactly what it needs.