November 6, 2026 · Pocatello Insulation

How to Stop Condensation in a Metal Shop or Pole Barn

If your shop rains on you on cold mornings, you're not alone. It's one of the most common calls we get from Southeast Idaho shop owners.

Why metal buildings sweat

When warm, moist air inside the building touches cold metal panels, the moisture condenses on the metal, the same way a cold drink sweats in summer. Heating the shop, parking a wet truck inside, or running equipment all add moisture.

Why fiberglass and bubble wrap fall short

Fiberglass batts and reflective bubble insulation leave gaps where moist air can still reach the cold metal. Over time, trapped moisture can soak insulation and rust fasteners.

How closed cell foam fixes it

Closed cell spray foam bonds directly to the metal, so there's no air gap for moisture to reach. It insulates, acts as a vapor barrier at about 2 inches, and adds stiffness to the panels. Many shops get 1 to 2 inches on the walls and 2 to 3 inches on the roof.