Roofs crowded with penetrations
Twenty curbs, conduit runs, old vents and dead pipe stubs. Foam wraps all of it without a single piece of cut-in flashing. That's where it earns its keep.
SPF Roofing, at a glance
Spray polyurethane foam goes down as a liquid, rises into one unbroken layer of closed-cell insulation, and gets protected with a silicone or acrylic topcoat. On a St. Louis building with a cluttered roof, low parapets and no budget for a full tear-off, it can be the smartest money on the property. On a roof with wet insulation underneath, it's throwing good money after bad. John Beal Roofing takes cores first. Free inspections. Call (314) 429-6000.
Foam gets oversold. You'll hear it fixes everything, lasts forever and never needs another dollar. That's not true, and any roofer who's actually sprayed it in a Missouri August will tell you the same. What foam does well is fill, slope and seal, all in one pass, over a surface that would be miserable to detail by hand.
It's about three pounds per cubic foot when it cures, roughly R-6.5 per inch, and it bonds to the substrate instead of being fastened through it. That last part matters here. Every fastener you don't drive is one more hole the wind can't work on and one more thermal bridge you don't have.
The Honest Version
When Foam Is The Right Call
Adding slope without a tear-off
Foam can be built up thicker at the low spots to push water toward the drains. It's the cheapest way to correct minor ponding on a sound deck.
Ponding water on flat roofsOld gravel BUR you'd rather not haul
Spud the loose stone, prep the surface, and spray over it. Skipping a gravel tear-off saves real dollars and a lot of dumpsters.
Built-up roofingBuildings that need R-value now
Three inches of foam is roughly R-19 added to a roof that may have had R-8. Utility bills on a big open span notice that.
Metal roof retrofits
Sprayed over an existing panel roof, foam locks the panels down, stops fastener leaks and kills the drumming in a hailstorm.
Commercial metal roofingWhere it's the wrong answer
Wet insulation, a rotted deck, heavy grease from a kitchen exhaust, or a roof with constant foot traffic. In those cases we'll tell you to tear off.
Commercial roof replacement
Installation
What A Foam Job Actually Involves
Weather rules everything. Foam won't bond to a damp deck, and it doesn't like wind over about 15 mph because overspray drifts onto cars two lots over. We watch the forecast and we mask everything downwind.
Prep is most of the job. Power-wash, dry, spud loose aggregate, cut out any wet insulation we found in the cores, and repair the deck. Foam sprayed over a wet substrate blisters, and it'll do it within a year.
Then it goes down in lifts, usually one to one-and-a-half inches at a pass, until we hit the specified thickness. Same day, once it's cured, the coating goes over it — foam left bare in the sun starts breaking down fast.
Budget for a recoat. Around 12 to 15 years in this climate you add another coat of silicone and the clock resets. That's the trade: a lower up-front number and a maintenance item you can't skip.
If you're weighing foam against a fluid-applied restoration on an existing membrane, our roof coatings page covers that comparison. If the roof under discussion is single-ply, start with TPO or EPDM. And whatever route you take, get the warranty terms in writing — our warranty guide explains what the words on those certificates mean.
Common Questions
How long does a foam roof last in St. Louis?
The foam itself can go 30 years or more if it's kept coated. The coating is the wear layer, and it needs renewing roughly every 12 to 15 years here. Skip the recoat and UV will chew through the foam.
Does hail wreck a foam roof?
Foam holds up better than most people expect. Large hail can dent the coating and bruise the surface, and we cut those spots out and re-spray them. It's a patch, not a replacement, which is a real advantage after a Missouri storm.
Can you spray foam over our existing roof?
Often, yes, but only after cores come back dry. We cut samples, look at the insulation, and check the deck. If there's trapped moisture, foam seals it in and you've bought a very expensive lid.
Will the smell get into the building?
There's an odor during the spray and for a short time after. We identify fresh-air intakes ahead of time, shut them down or reroute them during the work, and schedule around occupied hours where it matters.
What warranty comes with it?
Manufacturer coverage on the foam and coating system, plus our own workmanship warranty. On qualifying work that's a lifetime workmanship warranty from a company that's been in St. Louis since 1947.
Free Spray Foam Roof Evaluation
Tell us about the property and a dispatcher will call to schedule. No cost, no obligation.