RESTORATION

Agribusiness Service Inc.

Spray polyurethane foam with protective coating over metal

Project Overview

Agribusiness Service Inc. is located at 11320 Washington Highway in Ashland, in Hanover County. The building has a low-slope metal roof that runs up against a taller metal wall.

The metal roof had rusted. The owner needed the roof protected without replacing the metal panels.

Job Photos

Metal roof with rust spots across the panels before the spray foam work (Agribusiness Service Inc., Ashland, VA) — Metal roof with rust spots across the panels before the spray foam work

Rust running along a seam line on the existing metal panels (Agribusiness Service Inc., Ashland, VA) — Rust running along a seam line on the existing metal panels

Crew spraying polyurethane foam over the metal roof (Agribusiness Service Inc., Ashland, VA) — Crew spraying polyurethane foam over the metal roof

Fresh spray foam covering the panels and turning up onto the wall (Agribusiness Service Inc., Ashland, VA) — Fresh spray foam covering the panels and turning up onto the wall

Coated spray foam roof following the shape of the metal panel ribs (Agribusiness Service Inc., Ashland, VA) — Coated spray foam roof following the shape of the metal panel ribs

Finished white coating over the foam at the roof-to-wall transition (Agribusiness Service Inc., Ashland, VA) — Finished white coating over the foam at the roof-to-wall transition

The Challenge

Rust had spotted the panels and was running along a seam line. Rust on a metal roof gets worse over time, and the fasteners, seams and laps are where it usually leads to leaks first.

The roof also meets a tall wall along one side, so that transition had to be covered and sealed along with the field of the roof.

Our Solution

We installed spray polyurethane foam directly over the existing metal roof and finished it with a protective coating. The foam covered the panels and ran up onto the wall at the transition, and the coating went over all of it.

1We prepared the existing metal roof for the foam.
2We sprayed polyurethane foam over the metal panels.
3We carried the foam up onto the wall where the roof meets it.
4We applied a protective coating over the foam.

Why This Approach

Spray polyurethane foam is applied as a liquid that expands and bonds directly to the metal, so it forms a continuous, fully adhered layer over seams, fasteners and laps. That covers the details that tend to leak on metal roofs without removing any panels. Foam also adds insulation to the roof. It needs a coating on top, because foam breaks down in sunlight, so the coating is what protects it from UV and weather.

Results

Rusted metal roof covered with spray polyurethane foam
Foam carried up onto the wall at the roof transition
Protective coating over the foam
Existing metal panels left in place

Common Questions

Can spray foam be applied over a rusted metal roof?

Yes, as long as the metal is still structurally sound. Loose rust and dirt are cleaned off first so the foam bonds well. The foam then covers the panels, seams and fasteners in one continuous layer. Panels that have rusted through may need to be repaired before foaming.

Why does spray foam roofing need a coating?

Polyurethane foam is not UV stable. Sunlight breaks down the surface over time, so the foam is always covered with an elastomeric coating that protects it from UV and weather. The coating is renewed periodically to keep the foam protected.