Insulation Types Explained
Choosing the right type of insulation depends on the location being treated, the home's construction, budget, and performance goals. In Renfrew County's Climate Zone 6, air sealing is as important as R-value — choosing a product that both insulates and seals air movement is particularly valuable in this cold climate.
Spray Foam Insulation
Spray polyurethane foam (SPF) provides both insulation and air sealing in a single application, making it particularly valuable in Zone 6 where air infiltration is a major source of heat loss. It comes in two types:
- Open-cell spray foam: R-3.5 to R-4.5 per inch. Softer, more flexible, vapour-permeable. Used in attics and walls where some vapour movement is acceptable. Cost-effective for large open-attic spray applications.
- Closed-cell spray foam: R-6 to R-7 per inch. Rigid, highly impermeable to moisture and air. The preferred choice for basement walls, rim joists, crawlspaces, and any below-grade or moisture-prone application in Renfrew County homes.
Blown-In Cellulose Insulation
Made from recycled paper products treated for fire retardancy, blown-in cellulose offers an R-value of approximately R-3.5 per inch and is an excellent retrofit choice. It is pneumatically installed and fills around existing framing, wiring, and obstructions without disturbing the structure. For attic top-ups and full attic installations in Renfrew County, blown-in cellulose is the most common and cost-effective material. Dense-pack cellulose (blown at high density into wall cavities through small drilled holes) is the primary option for retrofitting existing closed walls.
Fiberglass Batt Insulation
Pre-cut fiberglass batts — R-3.2 per inch — fit between standard framing members and are the typical choice for new construction walls and exposed attic renovation work. They are widely available and can be installed DIY in open framing situations. Mineral wool (rock wool) batts are an upgraded alternative: slightly higher R-value, better fire resistance, and superior sound attenuation. In a retrofit, batts are practical only when framing is exposed — they cannot be installed in closed existing walls without opening them.
Rigid Board Insulation
Extruded polystyrene (XPS), expanded polystyrene (EPS), and polyisocyanurate (polyiso) rigid boards are used for basement exterior walls, under concrete slabs, and as continuous exterior insulation on wall assemblies. Rigid board provides a thermal break over framing — something batts alone cannot achieve. R-value ranges from approximately R-3.8 per inch (EPS) to R-6.5 per inch (polyiso). In Renfrew County, basement exterior insulation with rigid XPS board is common in energy retrofit projects.
Choosing the Right Type for Renfrew County
For most Ottawa Valley homes, the highest-return improvement is attic insulation and air sealing. Blown-in cellulose is cost-effective and performs well; spray foam is better for complex attic geometries or where air sealing is the primary concern. For basements and rim joists, closed-cell spray foam is the recommended choice due to its moisture resistance. For wall retrofits, dense-pack cellulose through drilled holes is the primary option in existing homes.
See our Insulation Cost Guide for price ranges by type, or return to the Insulation Services main page for a complete guide including Ontario code requirements and contractor qualifications.