Frequently Asked Questions About Home Insulation
What R-value is required for attic insulation in Ontario?
Ontario's Building Code Supplementary Standard SB-12 requires attic insulation of at least R-60 in Climate Zone 6, which covers Smiths Falls and all of Renfrew County. Homes built before the current code may have R-12 to R-20. Retrofitting to R-60 can reduce heating costs by 30-50%.
How much does attic insulation cost in Smiths Falls?
Costs vary by material and attic size. Blown-in cellulose ranges from $1.50 to $2.50 per square foot, blown-in fibreglass from $2.00 to $3.50 per square foot, and batts from $1.00 to $2.00 per square foot. A full 1,000-square-foot attic installation including air sealing and baffles typically costs $2,000 to $6,000.
What is spray foam insulation and when is it used?
Spray foam is a polyurethane insulation applied as a liquid that expands into an airtight foam layer. Open-cell foam provides R-3.6 to R-4.0 per inch and is best for interior wall cavities. Closed-cell foam provides R-6.0 to R-7.0 per inch and also serves as a vapour barrier, ideal for rim joists, crawlspaces, and cathedral ceilings.
Do I need a permit to add insulation in Ontario?
Yes, most insulation upgrades require a building permit under Part 9 of the Ontario Building Code (O. Reg. 332/12). This includes blown-in attic insulation, spray foam, and wall insulation. The Town of Smiths Falls issues permits for municipal properties, while Lanark County covers surrounding townships. Permit fees are generally $100-$400.
What is a vapour barrier and is it required?
A vapour barrier is a layer of material (typically 6-mil polyethylene) that restricts moisture diffusion through building assemblies. In Ontario's cold climate, vapour barriers are required on the warm side of insulation to prevent interior moisture from condensing inside walls. Closed-cell spray foam can replace a separate vapour barrier in some applications.
How do I know if my insulation is adequate in an older Smiths Falls home?
Look at the attic insulation depth — if you can see the ceiling joists, you likely have R-20 or less. Check for frost on attic roof sheathing in winter, which indicates air leakage. Signs like ice dams, high energy bills, and uneven room temperatures all suggest inadequate insulation. A professional energy audit with blower door testing provides definitive answers.
What causes ice dams in Rideau Valley winters?
Ice dams form when heat escaping through an under-insulated attic warms the roof deck, melting snow from below. The water runs down the roof and refreezes at the colder eaves. Smiths Falls homes with R-20 or less in the attic are highly susceptible. Proper attic insulation to R-60, combined with adequate ventilation and air sealing, prevents ice dams.
Blown-in vs. batt insulation — which is better?
Blown-in insulation (cellulose or fibreglass) provides better coverage in irregular attic spaces, fills around obstructions, and is more effective at reducing air movement. Batts are easier to install for DIYers in open cavities but can leave gaps around wiring and pipes. For Smiths Falls attics, blown-in cellulose at R-60 is generally the best balance of cost and performance.
Can I insulate my own attic in Ontario?
Yes, homeowners can install batt insulation or rent a blown-in insulation machine from rental centres in Smiths Falls or Perth. However, you must still obtain a building permit. DIY installation risks include improper air sealing, inadequate depth, blocked soffit vents, and missing vapour barrier requirements, which can reduce performance and cause moisture problems.
What is thermal bridging?
Thermal bridging occurs when heat travels through solid building materials (like wood studs or steel framing) that have lower R-value than the insulated cavity between them. This reduces the effective R-value of a wall assembly by 15-30%. Continuous exterior insulation or insulated sheathing can substantially reduce thermal bridging in Smiths Falls homes.
How long does spray foam insulation last?
Spray foam insulation, when properly installed, lasts the lifetime of the building — typically 50 years or more. It does not settle, compress, or degrade significantly over time. However, improper installation (incorrect mixing ratios, wrong temperature, inadequate thickness) can cause shrinkage or poor adhesion. Always use a qualified contractor with spray foam certification.
What is SB-12 and does it apply to my Smiths Falls home?
SB-12 is Ontario's Supplementary Standard for energy efficiency, part of the Ontario Building Code (O. Reg. 332/12). It sets minimum R-values by climate zone and building component. For Smiths Falls in Climate Zone 6, SB-12 requires attic insulation of R-60, wall insulation of R-23 effective, and basement insulation of R-17 to R-22. SB-12 applies to new construction and major renovations.
Do I need a permit for spray foam insulation in Smiths Falls?
Yes, spray foam insulation installation typically requires a building permit. This applies whether you are insulating rim joists, a crawlspace, or attic surfaces. The Town of Smiths Falls and Lanark County both require permits for insulation work. A permit ensures the work meets Ontario Building Code standards, including fire separation requirements for spray foam.
