The Problem With Exposed Spray Foam

Spray polyurethane foam (SPF) insulation has become one of the most popular choices for Muskoka homeowners over the past decade. It seals air gaps, manages moisture, and delivers excellent thermal performance — especially in the harsh Ontario winters that Muskoka is known for.

But here's the thing most people don't realize until it's too late: exposed spray foam is not permitted in occupied or accessible spaces under the Ontario Building Code.

If your basement, crawlspace, or garage has spray foam on the walls or ceiling that isn't covered with drywall or a certified thermal barrier coating, you likely have a code compliance issue — especially during a sale, renovation permit, or insurance inspection.

What Does the Building Code Actually Say?

The Ontario Building Code requires that spray polyurethane foam insulation be separated from the interior of a building by a thermal barrier. The intent is fire safety: SPF foam burns and produces toxic smoke. A thermal barrier slows the spread of flame and gives occupants more time to evacuate.

The most common thermal barriers are:

Drywall (minimum 12.7mm / half inch) — the standard in finished spaces
DC315 intumescent coating — a spray-applied alternative designed specifically for exposed SPF

For many basements, crawlspaces, garages, and mechanical rooms, installing drywall over spray foam is impractical or undesirable. That's where DC315 comes in.

What Is DC315 and Why Is It Used in Muskoka?

DC315 is a water-based intumescent coating manufactured specifically for application over spray polyurethane foam. When exposed to heat, it expands and chars — creating a physical barrier that slows flame spread.

For Muskoka homeowners and cottagers, DC315 has become the preferred solution because:

It's non-invasive — no framing, no drywall, no disruption to the space
It preserves ceiling height — critical in low-clearance basements and crawlspaces
It's fast — most projects are completed in a single day
It passes inspections — when properly applied by a specialist

When Do You Need It?

You need a thermal barrier coating if any of the following applies:

Spray foam is visible on any wall, ceiling, or floor assembly in an occupied or accessible space
You're selling your home and a home inspector has flagged exposed foam
You pulled a renovation permit and the inspector is requiring compliance
You're completing a cottage renovation or winterization project

Pro Tip: If you can see the spray foam from a finished or accessible space, assume it needs a thermal barrier.

Pricing in Muskoka

Typical pricing for DC315 application in Muskoka 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.

Local Insight

The most common scenario we see across Muskoka is spray foam applied during a cottage renovation or basement insulation project, with no follow-up thermal barrier application. Most homeowners or contractors simply don't know it's required until an inspector or real estate agent flags it.

The good news: DC315 is a fast, affordable, and non-disruptive fix.

If you need DC315 applied to pass inspection or bring your Muskoka property up to code, contact us today. We'll give you a clear answer and a straightforward quote.

Why Exposed Spray Foam in Your Muskoka Basement Needs a Thermal Barrier