Spray polyurethane foam is the system we recommend most for metal building retrofits and roofs with irregular geometry, which come up often on the ag-adjacent and light-industrial buildings scattered around the counties surrounding Evansville. It's self-adhering, self-flashing at most penetrations, and adds insulation value that a membrane roof alone doesn't.
A lot of the pole barns, ag-service buildings, and older metal warehouse structures around Princeton, Boonville, and the smaller towns that supply the Toyota assembly plant's commercial roofing team have roofs that were never insulated to modern standards. Spray foam applies directly over the existing metal panels, filling seams and fastener penetrations in one pass while adding an insulation layer that cuts heat gain in summer and heat loss in winter. That combination, waterproofing and insulation from a single application, is hard to match with a membrane system, which needs a separate insulation package underneath.
Foam also follows the roof's existing contours without seams running the length of every panel, so buildings with curves, ridges, and irregular rooflines don't create the seam headaches a sheet membrane would.
Foam's biggest vulnerability is moisture intrusion if the protective coating over it ever fails or gets damaged. Once water gets under the coating and into the foam, freeze-thaw cycling through an Indiana winter can expand trapped moisture and cause real damage to the insulation layer underneath. This is exactly why the topcoat and recoat schedule matter more with foam than with almost any other roofing system, a foam roof with a compromised coating degrades faster than most owners expect.
We inspect foam roofs on a tighter cycle than membrane roofs for this reason, since catching a coating breach early is the difference between a small patch repair and a section that needs to be cut out and replaced.
Foam itself isn't UV-stable and needs a protective coating, usually acrylic or silicone, applied over it to block sun exposure. That coating wears over time from our long summer UV load and needs recoating on a cycle, generally somewhere in the range of every 10 to 15 years depending on coating type and thickness. Owners considering foam need to budget for that recoat cycle as part of the system's total cost of ownership, not think of the initial install as a one-time expense.
Foam application requires the right temperature and humidity window, which limits the installation season more than membrane roofing does. Our humid summer stretch can actually work against foam application on the most saturated days, and installers need dry substrate and appropriate weather conditions to get proper cell structure and adhesion. We schedule foam projects around forecast windows more carefully than we do for single-ply membrane work.
Foam is a strong fit for metal building retrofits, roofs with a lot of curves or penetrations, and buildings where added insulation value offsets the system's total cost. It's a weaker fit for owners who won't commit to the recoat maintenance schedule, or for flat roofs where a membrane system is simpler to inspect and repair over the long run. We're direct with owners about that maintenance commitment before recommending foam, since a neglected foam roof fails harder than a neglected membrane roof.
We put foam roofs on a twice-yearly inspection schedule rather than the standard annual walk we'd do on a membrane roof, checking specifically for coating wear, blistering, or any spot where the topcoat has thinned enough to expose foam underneath. Catching a small coating breach early is a patch repair measured in square feet; missing it for a season or two can mean cutting out and replacing a section of foam that's absorbed moisture.
With a maintained coating and recoat schedule, foam roofs commonly reach 20 to 30 years of service life, though that depends heavily on staying current with recoat intervals.
In some cases yes, as a recover option if the existing roof is dry and sound, though we evaluate the substrate carefully first since trapped moisture underneath is exactly the failure mode foam is most vulnerable to.
Yes, foam is used on flat roofs too, though for straightforward flat roofs with good drainage, a membrane system is often simpler to maintain and inspect over the long term.
Water finds its way into the exposed foam, and freeze-thaw cycling through winter can expand that trapped moisture and cause the foam to degrade or delaminate in that area, often requiring the damaged section to be cut out.
It depends on the specific chemical exposure and coating type. We evaluate exhaust exposure the same way we would for any roofing system before recommending foam in that setting.