Choosing a metal roof comes down to four decisions: panel profile, steel gauge, paint finish and the details around the panels. Standing seam with concealed clips is the usual residential choice, but the right specification depends on your roof’s slope, exposure and complexity.
This is the second guide in a series. Part 1 compares standing seam metal with asphalt shingles. Here we go through what to specify and what to ask. Wind Proof Roofing LLC offers standing seam metal roofing on Whidbey Island, in Anacortes and across the North Puget Sound, a wet, windy region where coating, flashing and ventilation choices matter.
In this guide
Panel Profiles: Standing Seam Is Not the Only Option
The profile determines how the roof sheds water, how it resists wind, how it handles temperature movement and how it looks.
Standing seam, snap-lock
- Concealed fasteners, so no screw heads sit on the surface
- Panels lock together by their formed edges, which speeds installation
- Suited to roofs with enough slope for the specific profile
Standing seam, mechanical seam
- Seams are folded closed on site with a seaming tool
- Commonly used on low-slope roofs and exposed sites
- More labor, and generally a tighter seam
Exposed-fastener panels
- Screws pass through the face of the panel
- Lower material and labor cost
- Washers and screws age and need periodic checking, and each fastener is a possible leak point
Minimum slope is set by the manufacturer for each profile, so confirm the figure for the exact profile being quoted and compare it with every roof plane. Where the slope is borderline, ask whether mechanical seam is a better fit, and ask the contractor to explain the choice in writing.
Gauge: Thicker Steel Has a Lower Number
Gauge describes steel thickness, and a lower number means thicker metal. Residential panels are commonly offered in 29, 26 and 24 gauge.
- 29 gauge is the thinnest and the most flexible. It dents and shows waviness more easily.
- 26 gauge is a common middle option.
- 24 gauge is stiffer, which helps it stay flatter and resist denting.
Thicker steel resists foot traffic, falling debris and denting better, and it keeps a flatter face when panels expand and contract. It also costs more. The practical question is how much stiffness your roof needs. A long, exposed roof, or one with trees overhead, gains more from heavier gauge than a short, sheltered roof does.
Gauge is not the only factor in wind performance. Clips, edge metal and fastening pattern matter as much. A heavy panel with poor edge detailing will still lift at the eaves.
Paint Finish: Ask What the Coating Actually Is
The coating protects the steel from UV and moisture and holds the color.
- PVDF coatings (Kynar 500 is a common brand name) are a premium option known for color retention and resistance to chalking. Wind Proof’s snap-lock standing seam project in Anacortes used a Kynar 500 finish.
- Silicone-modified polyester (SMP) and standard polyester cost less and generally carry shorter finish warranties.
Cloud cover, constant moisture and salt air near the water all argue for a quality coating. Whatever the finish, ask for the coating’s warranty document, not just a verbal description, and read what it covers: fade, chalking, and peeling usually have separate limits. Keep cut edges and fastener heads protected, since raw metal is where corrosion starts.
Details That Affect Performance and Cost
Panels are one part of the roof. Most leaks begin at the details, so these items should be spelled out in any scope:
- Underlayment. Use a synthetic product rated for the heat under metal, with self-adhered membrane at eaves, valleys and transitions.
- Valleys. The valley profile and the layer beneath it.
- Walls and chimneys. Step flashing, counter-flashing, crickets and kickouts.
- Penetrations. Boots or curbs matched to the panel profile.
- Clips. Type, spacing, and how the system allows for expansion.
- Edge metal. Eave, rake and ridge trim.
- Ventilation. Balanced intake and exhaust, so moisture does not condense under the deck.
- Roof geometry. More hips, valleys, dormers and walls mean more flashing and more labor.
This is why a price per square foot can mislead. Panel width, rib height, gauge, finish, valley design and flashing complexity all change the cost of the same house. Contractors who need to see the roof before quoting are usually working from a real scope.
What to Ask Every Contractor
- Which profile and manufacturer are you quoting, and what is its minimum slope?
- Is the seam snap-lock or mechanical, and why for my roof?
- What gauge and what coating, and where is the coating warranty in writing?
- What underlayment goes on the whole deck, and what goes at the valleys and eaves?
- How will you flash each wall, chimney, skylight and vent?
- How do the clips handle thermal movement, and how far apart are they?
- What is the ventilation plan?
- What happens if the deck is damaged under the old roof?
- What does the workmanship warranty cover, and who stands behind it?
Compare answers, not just totals. If two bids differ in price, the difference should be explainable in the scope.
If you want to check any contractor’s Washington registration, the state’s Labor and Industries site (lni.wa.gov) lets you look up contractors by name or registration number.
Frequently Asked Questions
Is standing seam the best choice for most homes?
It is the usual choice for residential metal because the fasteners are concealed and the panels can move with temperature. Exposed-fastener roofing costs less and can work on simple, sheltered buildings, but it needs more upkeep.
Which gauge should I pick?
Heavier steel (24 gauge) resists denting and stays flatter. Mid-range steel (26 gauge) is common. Pick based on exposure, panel length and budget, and ask your contractor why they recommend one over the other.
Is a PVDF finish necessary?
It is not required on every roof, but it is a good fit for wet, cloudy climates and salt air because of its color retention and corrosion resistance. A lower-cost coating can be acceptable if you understand its shorter warranty.
What shortens the life of a metal roof?
Usually the installation details, not the panel: poor flashing, wrong clip spacing, weak underlayment and shortcuts at valleys, walls and penetrations.
Should I choose the cheapest quote?
Choose the clearest scope. Gauge, finish, profile and installation details should all be written down so quotes can be compared on the same terms.
Next Step
Before you collect quotes, measure or have someone measure your roof’s pitch, note your longest panel run and describe how exposed the site is. Wind Proof Roofing’s inspections include walking the roof, documenting conditions, explaining why things fail and outlining options, so the quote starts from what is actually on your roof.