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ARMORTHANE PROTECTING YOUR WORLD

PROTECTING YOUR WORLD

ARMORTHANE PROTECTING YOUR WORLD

Metal Roof Paint:
What Lasts, What Peels
& When to Coat Instead

Which paint goes on galvanized, Galvalume, painted and rusted metal, the prep that decides whether it sticks, real 2026 costs, and where paint stops and a roof coating has to take over.
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  • Roof size and pitch
  • Panel type and metal
  • Rust, chalking or leaks
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$1.20–$2.70
Per sq ft to have a metal roof professionally painted
HomeGuide and Angi, 2026
2.4–4 mils
Dry film per coat of a typical DTM acrylic metal paint
Sherwin-Williams data sheet
6 months
Minimum weathering time for new galvanized steel before painting
Sherwin-Williams data sheet
70%
PVDF share of the resin a finish needs to be called Kynar 500
McElroy Metal

Metal roof paint is one of the cheapest ways to make a faded, chalky or lightly rusted steel roof look new again, and one of the easiest jobs to get wrong. Most failed metal roof paint jobs we get called to look at did not fail because the paint was bad. They failed because alkyd paint went on galvanized steel, because nobody washed off the chalk, or because the owner expected a 3 mil paint film to stop a leaking fastener. We manufacture polyurea and polyurethane coatings, and we will tell you straight: for a lot of roofs, a good acrylic paint is the right answer and our products are overkill. This guide covers which paint goes on which metal, the prep that decides whether it sticks, what it costs, and where paint stops and a real coating system has to take over.

Quick answer

For most painted, galvanized or Galvalume roofs, use a 100% acrylic direct-to-metal (DTM) paint over an acrylic bonding primer, applied in two coats at 50°F or warmer. Never put alkyd or oil-based paint on galvanized steel; the zinc turns it to soap and it peels. Wash off all chalk and dirt, remove loose rust to at least hand-tool standard, and let new galvanized weather about six months first. Expect $1.20 to $2.70 per sq ft professionally applied and a repaint in roughly 10 to 15 years. If the roof leaks at seams or fasteners, paint will not fix it; that needs a 20+ mil roof coating or a spray-applied membrane.

What's in this guide
  1. 1Paint vs. roof coating: the real difference
  2. 2The right metal roof paint for each metal
  3. 3Metal roof paint selector
  4. 4Finishes compared
  5. 5Paint quantity and cost calculator
  6. 6How to paint a metal roof so it stays
  7. 7When paint is the wrong answer
  8. 8FAQ
Start here

Metal roof paint vs. roof coating

People use "paint" and "coating" interchangeably, but on a metal roof they are different products doing different jobs, and the difference is mostly thickness.

A direct-to-metal acrylic like Sherwin-Williams Pro Industrial DTM goes on at 6 to 10 wet mils and dries to 2.4 to 4 mils per coat. Two coats gets you somewhere around 5 to 8 mils. That is plenty to restore color, block UV and slow corrosion on sound metal. It is not enough to bridge a gap.

A roof coating is built to be a membrane. Karnak's 404 Corrosion Proof metal base coat, for example, goes on at 1.5 gallons per 100 sq ft for 20 to 24 dry mils, and that is just the base coat before the finish coat. Elastomeric acrylic, silicone and polyurethane roof coatings are designed to stretch with the panels as they expand and contract, and to be paired with fabric and sealant at seams and fasteners. A spray-applied polyurea membrane is thicker again.

  • Paint is for appearance and corrosion protection on a roof that is still watertight: faded or chalking factory finish, surface rust on a barn roof, a color change.
  • A coating system is for leaks and life extension: seams opening up, fasteners backing out, widespread rust, or a roof you want to keep in service another 10 to 20 years without tearing it off.
  • A spray membrane is for the hard cases: badly corroded commercial roofs, hail-dented panels, roofs with lots of penetrations, or where you need a thick, seamless, fast-setting layer.
Rule of thumbIf water is getting in, buy a coating system. If water is not getting in and the roof just looks tired, buy paint. Most regrets come from mixing those up.

One more thing to know before you pick a color: dark roofs get hot. The U.S. Department of Energy notes conventional roofs can reach 150°F or more on a summer afternoon, while a reflective roof can stay more than 50°F cooler under the same sun. If the building is conditioned, a light color is worth considering. Our cool roof coating guide covers the numbers. Note that the ENERGY STAR roof products label ended on June 1, 2022, so check a product's Cool Roof Rating Council listing rather than an old ENERGY STAR claim.

Metal by metal

The right metal roof paint for each metal

The metal under the paint decides the primer, and the primer decides whether the job lasts. Here is how we sort it out on a site visit.

Most barns and sheds

Galvanized steel

Zinc-coated steel, often dull gray and spangled. Use an acrylic bonding primer and acrylic topcoat. Never alkyd or oil: Dunn-Edwards explains the zinc reacts with the fatty acids in alkyd resin and forms a soap-like layer that makes the paint delaminate. New galvanized needs to weather first; Sherwin-Williams calls for at least six months.

Common on newer roofs

Galvalume / Zincalume

Aluminum-zinc coated steel with a brighter, smoother look. Bare Galvalume is very reflective (about 0.75 initial solar reflectance in LBNL data) but has low emittance, so it still runs warm. Treat it like galvanized: clean, acrylic bonding primer, acrylic topcoat. Check the panel maker's guidance before painting a roof still under warranty.

Factory finish

Painted steel (SMP or PVDF)

Most colored panels came with a baked-on silicone modified polyester (SMP) or PVDF (Kynar 500) finish. Chalky SMP takes paint well after a thorough wash. PVDF is hard to bond to by design; manufacturers sell specific primers for it, such as Karnak's 702 K-Prep, made for a surface that "traditionally has been difficult to bond against."

Prep heavy

Rusted steel

Remove loose rust and flaking paint to at least SSPC-SP2 hand-tool cleaning, prime the same day you clean, and use a rust-inhibitive primer on the bare spots. Tight surface rust can be treated with a rust converter; heavy scale has to come off. If you can push a screwdriver through it, that panel needs replacing, not painting.

Lighter duty

Aluminum

Aluminum does not rust, but its oxide layer makes adhesion tricky. Degrease, scuff, and use a primer labeled for aluminum. Most painted aluminum roofs only need a repaint for looks.

Usually leave it

Copper and zinc

Copper and architectural zinc are chosen for the patina. Painting them is rarely worth it and often voids what made the roof valuable. If a copper roof leaks, it needs a sheet-metal repair.

Not sure what primer you need? Our metal primer guide goes deeper on bonding, rust-inhibitive and zinc-rich primers.

Selector

Metal roof paint selector

Tell the tool what metal you have and what shape it is in. It returns whether paint is the right call, the primer and topcoat type, the prep standard, and the mistakes to avoid for that combination.

Paint or coat?

What should go on this metal roof?

Logic follows the manufacturer guidance cited on this page: no alkyds on zinc (Dunn-Edwards), six months weathering for new galvanizing and SSPC-SP2 minimum on rust (Sherwin-Williams), and coating systems of 20+ dry mils where the roof leaks (Karnak 404).

Matters for new galvanizing
—
Verdict
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Primer
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Topcoat

    Side by side

    Metal roof finishes compared

    Click any column heading to sort. Film thickness is the total for a normal system, not one coat. Cost is installed, per square foot of roof.

    FinishTypical dry film (mils)Installed $/sq ftExpected lifeStops leaks?Best fit
    DTM acrylic paint, 2 coatsabout 5–8$1.20–$2.70Repaint every 10–15 yrsNoSound roof, color or rust touch-up
    Alkyd / oil enamelabout 4–6Similar to acrylicPeels on galvanizedNoBare, primed carbon steel only
    Elastomeric acrylic coating22–25$0.50–$3.007–20 yrsYes, with seam and fastener detailingSloped metal that drains
    Silicone roof coatingabout 22 per coat$1.50–$4.5010–15 yrsYes, with detailingLow slope, slow drainage
    Polyurethane roof coatingvaries by system$1.50–$4.0012–20 yrsYesFoot traffic, impact, hail areas
    Factory PVDF (Kynar 500)factory bakedNew panels only35-yr chalk and fade warranty typicalPanel system dependentNew construction, re-roofing
    Spray polyurea + aliphatic topcoatthick, set per specQuote per jobDepends on topcoat upkeepYes, seamlessCorroded commercial and ag roofs
    Sources: Sherwin-Williams Pro Industrial DTM data sheet (2.4–4.0 dry mils per coat); US Made Supply acrylic guide (22–25 dry mils two-coat); Karnak 670HS data sheet (24 wet mils at 91% volume solids); HomeGuide 2026 roof coating and metal roof painting costs; HomeGuide (acrylic 7–20 yrs, silicone 10–15 yrs); The Roofing Brief (polyurethane 12–20 yrs); Angi (repaint 10–15 yrs); Metal Sales PVDF warranty (35-year chalk/fade, 45-year film). Alkyd film estimate is ours.
    Calculator

    Metal roof paint quantity and cost calculator

    Most people under-buy paint for a metal roof because they measure the footprint of the building. The calculator corrects for roof pitch and for the extra surface in a ribbed or corrugated profile, then works out gallons of primer and paint.

    Estimator

    How much metal roof paint do I need?

    Surface = footprint x pitch factor (square root of 1 + (rise/12)²) x profile factor. Gallons = surface x coats / coverage, plus 10% waste. Profile factors are our geometry estimates for each panel shape. Pro cost uses $1.20–$2.70 per sq ft (HomeGuide, Angi 2026).

    DTM acrylic: 160–267
    Angi: $35–$70 acrylic
    —
    Paintable surface
    —
    Paint to buy
    —
    Primer to buy
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    DIY materials
    —

    Leaking or badly rusted?

    When paint is not enough, spray a membrane.

    Certified ArmorThane applicators spray seamless polyurea and polyurethane systems over corroded, leaking metal roofs on barns, shops and commercial buildings, sealing fasteners and seams in the same pass.

    Get a free quoteFind an applicator

    Contractors: become an applicator →

    Process

    How to paint a metal roof so it stays put

    Paint adhesion is decided before the can is opened. This is the sequence we train applicators to follow on any metal roof, whether the finish is a DTM acrylic or a spray-applied membrane.

    1. Set up fall protection and check for lead

      OSHA requires fall protection for roofing work 6 feet or more above a lower level, on low-slope and steep roofs alike. On homes, child care facilities and preschools built before 1978, assume old paint may contain lead; the EPA's RRP rule requires certified firms when anyone is paid to disturb it.

    2. Fix the roof before you paint it

      Walk every panel. Replace stripped or backed-out fasteners with oversized screws and new washers, reseal laps and flashings, and replace any panel with rust-through. Paint hides these problems for one season, then they come back under a nice new color.

    3. Wash off chalk, dirt and oil

      Chalk is the number one adhesion killer on old painted panels. Scrub with a cleaner-degreaser and pressure wash; Karnak specifies at least 2,000 psi for its metal base coat. Rinse well, let it dry, and do the hand-wipe test again. If your palm comes back white, wash again.

    4. Deal with rust properly

      Remove loose rust and flaking paint to at least SSPC-SP2 hand-tool cleaning, or SP3 power-tool cleaning on heavier spots. Prime bare steel the same day so it cannot flash rust overnight.

    5. Respect the zinc

      On galvanized and Galvalume, use an acrylic bonding primer and skip anything alkyd or oil based. New galvanized should weather first: six months per Sherwin-Williams. Some coating makers allow less for their own primers (Karnak asks 30 days before its 404 base coat), so follow the data sheet of the product you are using.

    6. Apply in the right weather, at the right thickness

      Most acrylic DTMs need 50°F or warmer and a dry forecast. Apply two coats; at 77°F a typical DTM is recoatable in about an hour. Check thickness with a wet film gauge: wet mils x volume solids = dry mils, so a 40% solids paint at 8 wet mils leaves about 3.2 dry.

    Do not paint the screws shutPainting over loose fasteners locks in the problem. If more than a few screws have backed out, the roof is moving and a flexible coating system with fastener detailing is the better fix.
    Honest limits

    When metal roof paint is the wrong answer

    We would rather you spend $3,000 on paint that is right for the roof than $15,000 on a coating you did not need. But there are clear cases where paint is a waste of money.

    Paint it

    Faded or chalky, no leaks

    Wash, prime where needed, two coats of acrylic DTM. This is the cheapest correct answer and it is what we would do on our own shop.

    Coat it

    Leaks at seams and fasteners

    Use an elastomeric roof coating system with fabric and sealant at every lap and screw head. Our metal roof coatings guide walks through the options.

    Coat it

    Low slope with ponding

    Paint and most acrylics do not like standing water. Look at silicone or a sprayed polyurea membrane, and fix the drainage if you can.

    Spray or replace

    Widespread corrosion or rust-through

    Replace perforated panels, then a thick seamless membrane is the long-term fix. See polyurea metal roof waterproofing.

    Related roof coating guides

    If your roof needs a coating rather than paint, compare acrylic roof coating for sloped metal that drains well, aluminum roof coating for low-cost reflectivity, and asphalt roof coating for old barn steel where looks do not matter. Our roof coating cost guide puts every option side by side on price.

    Where ArmorThane products fit

    Our applicators spray ArmorSeal 100 AL, a 1:1, 100% solids polyurea roofing liner with no solvents or VOCs. It is aluminized for reflectivity and bonds to steel, aluminum, copper and zinc. Because it is an aromatic formula, outdoor roofs get a UV TopCoat or ColorCoat within twelve hours. That is a membrane system, not a paint, and it only makes sense when the roof needs waterproofing. For the bigger picture across every roof type, start with our roof coating guide.

    FAQ

    Metal roof paint questions

    What is the best paint for a metal roof?

    For most galvanized, Galvalume and previously painted steel roofs, a 100% acrylic direct-to-metal paint over an acrylic bonding primer. It stays flexible, holds color and is safe on zinc. Use a rust-inhibitive primer on bare or rusted steel, and a specialty primer on PVDF (Kynar) finishes.

    Can I use oil-based paint on a galvanized metal roof?

    No. Zinc reacts with the fatty acids in alkyd and oil paints, a process called saponification, and forms a soapy layer that makes the paint peel. Use acrylic primer and paint on galvanized steel.

    How much does it cost to paint a metal roof?

    HomeGuide and Angi both put professional metal roof painting at $1.20 to $2.70 per square foot, or roughly $120 to $270 per roofing square. HomeGuide's national average is $2,340. Pressure washing, rust removal and fastener repairs add to that.

    How long does metal roof paint last?

    Field-applied paint typically needs redoing every 10 to 15 years, according to Angi, and sooner on roofs with poor prep or harsh sun. Factory PVDF finishes last far longer; one manufacturer warrants chalk and fade performance for 35 years.

    Do I need to prime a metal roof before painting?

    Prime any bare or rusted metal, all galvanized that has never been painted, and PVDF finishes. A sound, well-cleaned SMP finish can often take a DTM acrylic directly, but follow the paint's data sheet. When in doubt, prime.

    How long should new galvanized roofing weather before painting?

    Sherwin-Williams calls for at least six months of weathering before applying its DTM acrylic to galvanizing. Some roof coating systems allow less with their own primers, so follow the data sheet of the product you are using.

    Will painting a metal roof stop leaks?

    No. A paint film is only a few mils thick and cannot bridge open seams or loose fasteners. Leaks need repairs plus an elastomeric coating system, typically 20 mils or more, with reinforcement at seams, or a spray-applied membrane.

    Can you paint a metal roof yourself?

    On a low, walkable roof, yes, if you can meet basic fall protection and handle the washing and prep. Angi estimates DIY saves about $1,000 to $2,000 in labor. Steep, high or fragile roofs are a job for a pro.

    AT
    Written by the ArmorThane technical team. We have manufactured polyurea, polyurethane and polyaspartic coatings in Springfield, Missouri since 1989 and train the applicators who spray them on metal roofs, ag buildings and industrial structures. Always follow the data sheet of the paint or coating you use. Updated October 2026.

    Sources

    1. HomeGuide, metal roof painting cost (2026): homeguide.com/costs/metal-roof-painting-cost
    2. Angi, cost to paint a metal roof (2026): angi.com/articles/experts-discuss-metal-roof-paint-benefits-cost.htm
    3. HomeGuide, roof coating cost by type (2026): homeguide.com/costs/roof-coating-or-sealing-cost
    4. Sherwin-Williams, Pro Industrial DTM Acrylic product data sheet: paintdocs.com (Pro Industrial DTM Acrylic PDS)
    5. Dunn-Edwards, preparing and painting galvanized substrates: dunnedwards.com technical bulletin
    6. McElroy Metal, Kynar 500 vs. SMP: blog.mcelroymetal.com
    7. Metal Sales, PVDF system warranty: metalsales.us.com PVDF warranty
    8. Karnak, 404 Corrosion Proof and 702 K-Prep data: karnakcorp.com/product/404-corrosion-proof-metal-surface-base-coat
    9. US Made Supply, acrylic roof coating guide: usmadesupply.com/resources/guides/acrylic-roof-coating
    10. The Roofing Brief, roof coating types and solar reflectance reference (2026): theroofingbrief.com/roof-coating-types-and-cost
    11. The Roofing Brief, solar reflectance and SRI reference (LBNL data for bare Zincalume): theroofingbrief.com/roofing-solar-reflectance-sri-reference-2026
    12. U.S. Department of Energy, cool roofs: energy.gov/energysaver/cool-roofs
    13. Sheffield Metals, ENERGY STAR roof products sunset: sheffieldmetals.com
    14. OSHA 29 CFR 1926.501, fall protection: osha.gov 1926.501
    15. EPA, Lead Renovation, Repair and Painting Program: epa.gov/lead

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