Why metal roofs start leaking
Exposed-fastener metal roofs are held down by hundreds of screws, each with a rubber washer. Up here, those washers bake in strong sun and freeze on cold nights. They crack, the screws loosen as the panels expand and contract, and water finds its way in. Wind lifts edges and opens laps. Surface rust starts wherever the paint has worn.
What a coating system does
- Clean — wash off dirt and chalky paint; remove loose rust
- Prime — rust-inhibiting primer on rusted areas
- Fasten — tighten or replace loose and stripped screws
- Seal — every fastener, lap, seam and ridge cap
- Topcoat — a white or light reflective elastomeric over the whole roof
Coat or replace?
If the panels are still solid and attached to the framing, a coating system costs a fraction of new metal. If they're rusted through or bent from wind, those panels need replacing first. See metal roofing.
Cooler in summer
A reflective coat can make a big difference inside a metal-roofed home, shop or barn on a summer afternoon.
Cost
Metal roof coating often runs around $2.25–$4.50 per square foot, depending on rust, fastener work and roof size. See roof coating cost.
Call (505) 381-5017 for a free look at your metal roof.
Common questions
How long does a metal roof coating last?
Often 10 years or more with the right product and thickness, plus periodic fastener checks.
Can you coat a standing-seam roof?
It's rarely needed. Concealed-fastener roofs usually just need spot repairs.
Will it stop the rust?
Treating and priming rusted areas before coating stops surface rust from spreading.