Materials
	Insulation
	Air-barrier materials
	Vapour-barrier materials
	Health and safety considerations

Insulation

The main function of insulation is to keep the heat in. To be effective, insulation must be:

• resistant to heat flow
• able to fill the space completely and evenly
• durable

In some locations, it must be able to withstand exposure to heat or moisture.

Several different insulation materials may be used at various locations as part of the house envelope, depending on available space, ease of access and other installation requirements.

Within This Page

• The proper choice of insulation
• Summary of insulation types
  • Batt or blanket insulation
  • Loose-fill insulation
  • Vermiculite containing asbestos – Health Canada advisory
  • Rigid board insulation
  • Spray-foam insulation

The Proper Choice of Insulation

The proper choice of insulation depends on its final use. In most applications, good resistance to heat flow is not the only thing you will have to consider. In specific situations, insulation may also need some of the following properties:

• resistance to high temperatures
• resistance to moisture flow (can it reduce the movement of water vapour?)
• resistance to air movement (can it act as an air barrier?)
• a fire-rated protective covering

Once you have matched the material properties with the specific application, consider the following installation factors:

• Is it relatively easy to install?
• Is it the best buy for the space available (either high insulating value per dollar if you have lots of open space, or high insulating value per thickness if space is restricted)?
• Is it available locally?
• Will it be easy to install the insulation to fill the space completely?
• Can it conform to surface irregularities?
• Is it rigid enough to provide support for finished materials or resist pressures against its surfaces?
• Does one insulation require more accessory products than another (fire protection, framing, air and vapour barrier)?

In short, the choice of insulation will largely depend on how it will be used. Different types of insulation are commonly used for insulating walls, basements and attics. Fortunately, particular insulation jobs will quickly eliminate some materials, making the choice much easier.

Naturally, cost is a factor in the choice of material. Generally, the cost per RSI value is lower for loose-fill or batt-type materials than for rigid board or foam-type insulations. However, the price of the basic material is just one aspect. In some cases, high material costs may be offset by lower installation costs or the preference of the installer for a particular insulation technique. A better comparison can be made using the installed cost. This includes the cost of the insulation material plus the cost of required accessories and installation.

Insulations are manufactured from a wide range of materials, including melted glass spun into fibres, expanded volcanic rock, recycled newsprint and foam plastic.

However, there are only four basic forms of insulation that provide a ready means of classification: batt or blankets, loose-fill insulation, rigid or semi-rigid boards and spray-foam insulation. The following information describes these categories in detail.

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Summary of Insulation Types

Batt or Blanket Insulation

Batt or blanket insulation is relatively easy to install in accessible spaces such as exposed wall cavities and some attics. It conforms to slight surface irregularities and can be cut to fit. Safety equipment and protective clothing are required during installation.

Mineral Fibre

• includes 0.022 RSI/mm (3.2-R/in.) glass fibre
• includes 0.023 RSI/mm (3.3-R/in.) mineral wool
• is available in batts or continuous rolls (blankets)
• will not settle
• some products are non-combustible (check with the manufacturer)

Loose-Fill Insulation

Note: Unless otherwise indicated, all the insulation materials listed require the presence of an air barrier and a vapour barrier.

Loose-fill insulation is made from a variety of materials, with particles ranging in texture from granular to fluffy. Loose-fill insulation is excellent for filling irregular or inaccessible spaces. It is suitable for walls and floors and excellent in attics and enclosed spaces such as roofs where the space between the joists may be irregular or cluttered with obstacles. It is often handy for filling small spaces or covering ceiling joists. It is not appropriate for below-grade application.

Loose-fill insulation may be blown or poured. Pouring insulation will generally require more material than blowing insulation to achieve a specified RSI value. It is useful for topping up existing insulation in attics and accessible enclosed wall cavities and for filling in cracks and uneven spaces.

The proper installation of blown loose-fill insulation usually requires an experienced, well-trained technician. To achieve the full RSI value, the material must be installed following the manufacturer's instructions.

Safety equipment and protective clothing are required during installation. The most important aspect of installation is following the manufacturer's instructions.

Cellulose Fibre

• Made from shredded newsprint treated with chemicals that resist fire and fungal growth and inhibit corrosion.
• Because of its small particle size, can fill around obstructions such as nails or electrical wires within cavities.
• May reduce air leakage if installed to the proper densities.
• Blown
• Average RSI of 0.025/mm (3.6-R/in.), depending on the paper and chemical mix and the blown density.
• Proper blown density for enclosed cavities is 56 to 72 kg/m³ (3½ to 4½ lb./cu. ft.).
• Poured
• Insulating value of 0.024 RSI/mm (3.4-R/in.).
• Follow manufacturer's instructions for proper application techniques.

Glass Fibre

• A similar material to glass-fibre batts, but chopped up for blowing or pouring applications.
• Hand-poured glass fibre works best in open horizontal surfaces such as attics. Blown glass fibre can be used in both horizontal and vertical applications, but may be difficult to install in cavities that are partially blocked by nails, framing, electrical wiring, etc.
• For walls, the density of application is usually two to two and a half times the recommended rate of application for horizontal surfaces.
• Some classified as non-combustible. Check the manufacturer's specifications.

Blown

• Average insulating value of 0.020 RSI/mm (2.9-R/in.), depending on density.
• Follow manufacturer's instructions for proper application techniques.

Poured

• Insulating value of 0.021 RSI/mm (3.0-R/in.).
• Follow manufacturer's instructions for proper application techniques.

Mineral Wool (Slag and Rock Wool)

• Treated with oil and binders to suppress dust and maintain shape; a lubricant is added for blowing purposes. Similar to glass fibre in appearance and texture.
• Suitable for accessible attics and inaccessible areas such as wood-frame roofs, walls and floors.
• For walls, the density of application is usually two to two and a half times the recommended rate of application for horizontal surfaces.
• Good for insulating around masonry chimneys, as it will not support combustion.

Blown

• Average insulating value of 0.021 RSI/mm (3.0-R/in.), depending on the density at which it is blown in.
• Follow manufacturer's instructions for proper application techniques.

Poured

• Insulating value of 0.022 RSI/mm (3.2-R/in.).
• Follow manufacturer's instructions for proper application techniques.

Vermiculite

• An expanded mica material that was commonly used in older homes, although less readily available these days.
• Two types – untreated and treated. Untreated vermiculite absorbs moisture. Treated (water-repellent) vermiculite is coated with asphalt for use in areas of high moisture.
• Untreated vermiculite has an average insulating value of 0.016  RSI/mm (2.3-R/in.); treated vermiculite has an average insulating value of 0.017 RSI/mm (2.5-R/in.).
• Usually hand-installed.
• Suitable for both horizontal and vertical applications.
• For vertical applications, it is poured into the wall cavity and packed down with a heavy weight to make sure that the cavity is filled and to prevent future settling.
• Follow manufacturer's instructions for the proper application techniques.

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Rigid Board Insulation

Board insulations are manufactured from glass fibre or foam plastic materials. These materials have a high insulating value per unit thickness, although the cost per RSI value is greater than for loose-fill or batt/blanket insulations.

Insulating boards are lightweight and easy to cut and handle. Fitting them into irregular spaces, however, can be a tedious process. Some boards are now available with an attached fire-resistant, moisture-resistant or decorative covering. It is also possible to purchase specially designed boards that come with their own system of attachment. Regular board materials can be ordered pre-cut to specific sizes for an additional cost.

Glass-Fibre Boards

• Two types of high-density, semi-rigid glass-fibre board are commonly used in residential applications: one designed specifically for below-grade exterior use, the other an above-grade exterior sheathing.
• Above-grade type covered with a water-repellent breather-type building paper.
• Below-grade type has an insulating value of 0.029 RSI/mm (4.2-R/in.).
• The exterior sheathing has an insulating value of 0.031 RSI/mm (4.4-R/in

Expanded Polystyrene

• Produced by bonding coarse beads into rigid foam plastic boards. It is often referred to as "bead board."
• Manufactured in two densities:
  • low density, with an insulating value of 0.026 RSI/mm (3.7-R/in.); and
  • high density, with an insulating value of 0.028 RSI/mm (4.0-R/in.).
• High-density board is more resistant to moisture than low-density board and can be used on the exterior of foundation walls in dry, sandy soils.
• Must be protected from prolonged exposure to sunlight, solvents and some sealants. Use compatible sealants only. Ask your dealer for information.
• Requires covering with a fire-resistant material.

Extruded Polystyrene

• A foam plastic board with fine, closed cells containing a mixture of air and refrigerant gases (fluorocarbons).
• Manufactured in two densities:
  • low density, with an insulating value from 0.033 RSI/mm (4.7-R/in.) to 0.035 RSI/mm (5.0-R/in.); and
  • high density, with an insulating value of 0.035 RSI/mm (5.0-R/in.).
• Must be protected from prolonged exposure to sunlight or solvents.
• If joints are sealed properly, can perform as an air barrier, and certain thicknesses may perform as a vapour barrier.
• When installed on interior surfaces, must be covered with a fire-resistant material that is mechanically fastened to the building structure.

Polyurethane and Polyisocyanurate Boards

• Plastic boards made of closed cells containing refrigerant gases (fluorocarbons) instead of air.
• Usually come double-faced with foil; sometimes bonded with an interior or exterior finishing material.
• Faced boards have a typical insulating value of 0.040 RSI/mm (5.8-R/in.) to 0.050 RSI/mm (7.2-R/in.) and come in a variety of sizes.
• Must be protected from prolonged exposure to sunlight and water.
• Must be covered with a fire-resistant material.
• Can act as an air barrier (if seams are well sealed) and as a vapour barrier.
• Use generally limited to areas where a high RSI is desired and space is at a premium.

Phenolic Foam Boards

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Spray-Foam Insulation

This type of insulation is mixed on the job site by the contractor or installer. The liquid foam is sprayed directly onto the building surface or poured into enclosed cavities using a spray gun driven by a pump. The foam expands in place and sets in seconds. The installation contractor should be trained in the application of the specific product.

Polyurethane Foam

• A pale yellow foam of closed cells containing refrigerant gases (fluorocarbons).
• Typical insulating value of 0.042 RSI/mm (6.0-R/in.). Other values are sometimes quoted, but this value takes into account the loss of refrigerant gases over time.
• Sprayed onto surfaces in layers less than 50 mm (2 in.) thick and hardens in seconds.
• Can expand up to 28 times its original volume and should not be used in enclosed cavities.
• Can be used as an air barrier but not as a vapour barrier.
• Must be protected from prolonged exposure to sunlight and requires covering with a fire-resistant material when used indoors.

Semi-Flexible Isocyanurate Plastic Foam

• A combination of isocyanurate, resins and catalysts forms this open-celled, semi-flexible plastic foam insulation.
• Manufacturers' literature lists insulating value as 0.030 RSI/mm (4.3-R/in.).
• Some limitations on the thickness that can be applied.
• Can be used as an air barrier.
• Requires covering with a fire-resistant material.

Phenolic Foam

• Phenolic foam is currently available only as foamed-in-place insulation. It has an R-4.8 value per inch of thickness and uses air as the blowing agent.
• Must be protected from exposure to sunlight and water, and it can shrink up to 2 percent after curing, which increases the risk of voids being created where it is used.

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