Muskoka Thermal Coatings
DC315 Thermal Barrier Specialists · Muskoka, Ontario
Why Spray Foam Inspections Fail More Often Than They Should
Spray polyurethane foam is a technically sound insulation product. When it fails inspection, the foam itself is rarely the issue — it's the finish condition around it. Specifically, whether exposed foam surfaces have been properly protected with a compliant thermal barrier.
Across Muskoka, these failures are remarkably consistent. The same issues come up again and again — on new builds, cottage renovations, basement insulation projects, and pre-sale inspections. Most of them are entirely preventable, and when they do occur, the fix is almost always the same: a proper DC315 thermal barrier coating application.
Here's a breakdown of the most common failures we encounter and what it takes to resolve each one.
Failure 1: No Thermal Barrier at All
What it looks like: Spray foam applied to basement walls, rim joists, crawlspace ceiling, or garage surfaces — with nothing over it. The foam is visible and exposed.
Why it happens: The spray foam installer completed their scope of work correctly. But no one communicated to the owner or GC that a separate thermal barrier application is required afterward. The two trades are typically different contractors, and the handoff doesn't always happen.
How to fix it: DC315 thermal barrier coating applied by a qualified specialist over all exposed foam surfaces. For most Muskoka residential projects, this is a one-day application.
Failure 2: Partial Application — Coverage Gaps
What it looks like: DC315 or drywall was applied to some surfaces but not others. Walls are covered; rim joists are not. The main ceiling is coated; the area behind the HVAC air handler is bare. A section behind a structural beam was missed.
Why it happens: Partial applications happen when the applicator isn't thorough, when the scope wasn't clearly defined, or when certain areas were inaccessible at the time of application and never followed up on.
How to fix it: A comprehensive re-assessment of all foam surfaces, followed by a targeted application to cover every gap. All foam in an accessible space must be covered — there's no partial compliance.
Inspector Note: Inspectors will look in corners, behind pipes, and along rim joists. If there's a gap, it will be found.
Failure 3: Wrong Product Used
What it looks like: A coating was applied — it looks like DC315, it might even be labelled as fire retardant — but it doesn't meet the certification standard for use over spray foam plastic insulation.
Why it happens: Hardware store intumescent paints, general fire-retardant coatings, and even some professional-grade products are not certified under ICC-ES AC377 for use over spray foam. A well-intentioned contractor or homeowner applies something that looks right but doesn't qualify.
How to fix it: The non-compliant coating may need to be removed, or a full application of DC315 at the required thickness applied over it (depending on compatibility). Assessment determines the right approach. In most cases, a full DC315 application over the existing surface is the cleanest solution.
Failure 4: Insufficient Thickness
What it looks like: DC315 was applied, but not at the correct wet film thickness. The coating is present but too thin to meet the tested performance standard.
Why it happens: This is a common outcome when DC315 is applied by someone who isn't familiar with the product. Brush or roller application almost never achieves the required thickness. Spray application with improperly configured equipment can also result in under-thickness work.
How to fix it: Additional coats of DC315 applied to bring the total to the specified thickness. An experienced applicator can assess the existing coating and confirm what's required.
Failure 5: Incompatible Foam Substrate
What it looks like: DC315 was applied over a spray foam product that isn't on the tested and approved substrate list for DC315.
Why it happens: DC315 is tested for use over specific foam formulations from listed manufacturers. When applied over an untested or incompatible substrate, the ICC-ES certification doesn't apply — and the inspector may reject it.
How to fix it: Verify the foam product and review the DC315 compatibility list. If the foam is incompatible, options include: applying a compatible alternative thermal barrier system, or in some cases, drywall over the foam. Each situation requires individual assessment.
Failure 6: Foam Behind Non-Qualifying Materials
What it looks like: Spray foam was installed, then covered with fibreglass batts, vapour barrier, rigid insulation, or some other material the owner assumed would serve as a thermal barrier.
Why it happens: Common misconception. Vapour barriers, batt insulation, rigid foam, and plastic sheeting do not qualify as thermal barriers under the Ontario Building Code.
How to fix it: The non-qualifying material may need to be partially removed to access the foam surface, DC315 applied, then the other material reinstalled. Planning matters here — this is why the thermal barrier step should happen before other materials go over the foam.
Failure 7: No Documentation Available
What it looks like: DC315 appears to have been applied correctly, but the inspector requests product data sheets or ICC-ES evaluation reports and none are available.
Why it happens: Usually an administrative gap — the product was applied but no documentation was kept or provided.
How to fix it: An experienced DC315 applicator maintains current ICC-ES reports and product data sheets and can provide them on request. We include documentation support as a standard part of our service.
Pricing for DC315 Correction Work in Muskoka
Typical pricing ranges from $2.50 to $3.50 per square foot, with a minimum service fee of $1,500 depending on the size and scope of the project.
Correction work — where we're fixing a previous partial or non-compliant application — is assessed on the same basis, with additional consideration for prep requirements.
Local Insight
In Muskoka, the most common failure we're called to correct is the straightforward case: no thermal barrier at all. Spray foam went in during a basement renovation or cottage winterization, and the thermal barrier step simply never happened. The issue surfaces during a real estate inspection or when a future renovation permit triggers a code review.
It's not a complicated fix — but it needs to be done properly, by someone who knows the product and understands what inspectors are looking for.
Conclusion
Spray foam inspection failures in Muskoka are almost always preventable and fixable. The underlying requirement is simple: all exposed foam in occupied or accessible spaces needs a compliant thermal barrier. DC315, professionally applied, is the solution for the vast majority of cases.
If you need DC315 applied to pass inspection in Muskoka, contact Muskoka Thermal Coatings today for a fast and reliable quote.