Insulation FAQ — Renfrew County, Ontario

Renfrew County falls under Ontario Climate Zone 6, which has the highest insulation requirements in the province. Under the Ontario Building Code's supplementary standard SB-12, attic insulation must achieve a minimum of R-50. Many building professionals and energy advisors recommend R-60 for new construction or major renovations, as the additional cost is relatively small compared to the long-term energy savings.

Most older homes in Pembroke and across Renfrew County were built to much lower standards. A typical pre-1970s home may have only R-12 to R-20 in the attic — roughly one-quarter of what is now considered adequate for the local climate.

Costs for attic insulation in the Pembroke area depend on the type of material, the target R-value, and ease of access:

• Blown-in cellulose or fibreglass: $1.20 – $2.50 per sq ft installed
• Fibreglass batts: $0.80 – $1.50 per sq ft (DIY, materials only)
• Spray foam (open-cell): $2.50 – $5.00 per board foot
• Spray foam (closed-cell): $4.00 – $8.00 per board foot

A complete attic upgrade on a 1,000-square-foot home to R-50 using blown-in insulation typically costs $1,500 to $4,000. If existing insulation must be removed, add $500 to $1,500.

Spray foam insulation is a two-component polyurethane foam that is sprayed as a liquid and expands into a solid. There are two main types:

• Open-cell spray foam: R-3.5 to R-3.7 per inch. Softer, more flexible, and less expensive. Used for interior wall cavities, attic floors, and ceiling assemblies. Requires a separate vapour barrier.
• Closed-cell spray foam: R-2.0 to R-3.0 per inch but much denser and stronger. Acts as its own vapour barrier. Used for rim joists, crawlspaces, exterior walls, and areas exposed to moisture. Also adds structural rigidity.

In Renfrew County, spray foam is frequently used for rim joist insulation, crawlspace encapsulation, attic hatches, cathedral ceilings, and basement walls where traditional batt insulation is difficult to install effectively.

In most cases, adding attic insulation alone does not require a building permit in Renfrew County municipalities. However, if the work involves:

• Structural modifications to the roof or ceiling assembly
• Installation of a new vapour barrier where one did not exist
• Alterations to the building envelope that affect fire resistance
• Work requiring changes to electrical wiring or HVAC systems

...a permit may be required. Always check with the Renfrew County Building Department or your local municipal office before starting.

A vapour barrier is a material — typically 6-mil polyethylene sheeting — installed on the warm side of insulation (the interior side in Renfrew County's climate) to prevent moisture-laden indoor air from entering the wall or ceiling cavity. When warm, humid indoor air hits a cold surface inside the wall, condensation occurs, which can lead to mould, rot, and reduced insulation effectiveness.

In Ontario Climate Zone 6, a vapour barrier with a perm rating of less than 1 (i.e., vapour retarder class 1 or 2) is required by the Building Code for most exterior wall and ceiling assemblies. Closed-cell spray foam, at sufficient thickness (typically 2+ inches), qualifies as a vapour barrier. Open-cell spray foam does not — it requires a separate vapour barrier.

There are several signs that may indicate inadequate insulation in a Renfrew County home:

• Visual inspection: Go into the attic. If you can see the tops of the ceiling joists, you almost certainly need more insulation. Measure the depth and compare to R-value charts for your material.
• Ice dams: Large icicles or ice buildup at the eaves in winter is a strong indicator of heat loss through the attic.
• High heating bills: Compare your heating costs to typical homes of similar size in the area.
• Drafty rooms: Cold spots near exterior walls or ceilings suggest poor insulation or air sealing.
• Uneven temperatures: Significant temperature differences between rooms, especially upstairs versus downstairs, can indicate insufficient attic insulation.

The most reliable assessment comes from a professional energy audit, which includes a blower door test and thermal imaging to identify leaks and insulation gaps.

Ice dams form through a simple mechanism: heat escaping from the home warms the roof deck, melting snow at the upper roof surface. The meltwater runs down the slope under the snow, then refreezes when it reaches the cold eaves (which project beyond the heated space). The ice builds up into a ridge that traps subsequent meltwater behind it, which can then leak under shingles and into the home.

In Pembroke and across Renfrew County, the combination of heavy snowfall (200+ cm annually), frequent temperatures below −25°C, and a large inventory of older, under-insulated homes makes ice dams a seasonal epidemic. The primary fix is increasing attic insulation to R-50+ combined with air sealing all penetrations through the attic floor (plumbing stacks, wiring, recessed lights, attic hatches) and ensuring adequate attic ventilation to keep the roof deck cold.

Each has advantages depending on the application:

Blown-in insulation (cellulose or fibreglass loose-fill) is usually the better choice for Renfrew County attics because it flows around obstructions — wiring, plumbing vents, truss webs, junction boxes — without leaving gaps. Cellulose in particular has better air-sealing properties due to its density and tendency to settle into a tight blanket. Professional installation achieves consistent depth and R-value across the entire attic floor.

Fibreglass batts are less expensive and can be installed by a DIY homeowner, but they require careful cutting around every obstruction. Gaps, compression, and poor fitting are common with batt installation in complex attic spaces, which reduces effective R-value. Batts work well in new construction with open, regular ceiling cavities or in wall applications where they fit between standard-spaced studs.

For existing homes in Renfrew County, blown-in is typically the recommended approach for attic upgrades.

Yes. Ontario homeowners are permitted to install their own attic insulation. Many building supply stores (Home Depot, Rona, Lowe's) sell blown-in fibreglass and cellulose and offer free rental of the blowing machine. Do-it-yourself batt installation is also straightforward for simple, open attic spaces.

However, the Ontario Building Code's requirements — minimum R-values, vapour barrier rules, and air sealing requirements — still apply to DIY work. The most common mistake homeowners make is skipping air sealing before adding insulation. Without sealing the gaps around plumbing stacks, wiring, recessed lights, and the attic hatch, the new insulation will underperform and moisture problems may develop.

If you choose the DIY route, budget extra time for air sealing. Caulk, spray foam in a can, and weatherstripping are the primary materials needed.

Thermal bridging occurs when heat travels through solid, conductive building materials — such as wood studs, concrete, or steel framing — that bridge the gap between the warm interior and cold exterior. These materials bypass the insulation, creating a path for heat loss that reduces the effective overall R-value of the wall or ceiling assembly.

Example: A standard 2×6 wall with fibreglass batts has a nominal R-value of approximately R-20 or R-22. But because wood studs have an R-value of only about R-1.25 per inch, the heat passing through the studs (which occupy roughly 15–25% of the wall area) reduces the whole-wall effective R-value to perhaps R-14 to R-16. This is why the Building Code now specifies "effective R-value" rather than nominal R-value.

Solutions for reducing thermal bridging include continuous exterior insulation (rigid foam sheathing over the studs), insulated sheathing, double-stud wall systems, and closed-cell spray foam (which has higher R-value per inch and can reduce framing percentages in some designs).

Spray foam insulation is one of the most durable insulation products available. When properly installed, both open-cell and closed-cell spray foam have a lifespan of 30 to 50 years or longer. Unlike fibreglass batts or blown-in cellulose, spray foam does not settle, compress, or degrade from moisture exposure (closed-cell is waterproof; open-cell resists moisture well but is not fully waterproof).

One important caveat: spray foam degrades in direct sunlight. It must be covered with a thermal barrier (drywall, plywood, or intumescent coating) in occupied spaces and with UV-resistant coating if exposed in mechanical rooms or crawlspaces. Properly protected and installed, spray foam can last the life of the building.

SB-12 is the Supplementary Standard SB-12 under the Ontario Building Code, which sets minimum energy efficiency requirements. It was significantly updated in 2017 to raise insulation levels above the base building code. SB-12 divides Ontario into climate zones; Renfrew County is in Climate Zone 6, the most demanding zone.

Key SB-12 requirements for Zone 6:

• Attic / ceiling: R-50 minimum (R-60 recommended)
• Above-grade walls: R-24 effective minimum
• Floors over unheated spaces: R-28 minimum
• Basement walls (interior): R-20 minimum
• Slab / crawlspace perimeter: R-12 minimum

SB-12 applies to new construction and major renovations (those involving building permits for structural or envelope changes). It does not retroactively require existing homes to be upgraded. However, should major renovations be planned, meeting SB-12 standards will be required by the building department.