Improve Home Performance with Spray Foam Insulation

Published on: July 31, 2012


With today’s rising energy prices and climate change concerns, many people are looking for ways to make their homes and commercial buildings more energy efficient. In most parts of North America, heating and air conditioning are responsible for approximately half of the power expended in residential buildings and offices.

The government is introducing ever more stringent energy efficiency standards for appliances, and choosing an Energy Star product can help you save even more money. However, switching to a more efficient furnace, boiler and/or air conditioner is only half the battle. If your building cannot retain the conditioned air, then you may be spending much more than you need to on heating and air conditioning.

Insulation, air tightness and ventilation

If your home or commercial building is older or was not well built, then there may be a great deal of room for improvement in the building envelope. The building envelope consists of the walls, windows, doors and roof. A tight, efficient and healthy building envelope will have adequate wall and attic insulation, and it will be fairly air-tight while still providing good ventilation. It will stay dry and will not trap moisture, especially not in the vicinity of wood, drywall or paint.

Both moisture and heat can be transported in air, and most buildings lose more heat through air leakage than by diffusion through the walls and roof. Spray foam insulation can address both problems. Spray foam doesn’t just provide a good R-value, it can also seal leaks.

Spray foam insulation is in many ways an ideal concept

Spray foam, like loose fill insulation, can be blown into the walls of older stick-framed buildings without making it necessary to remove the plaster or drywall. There’s no reason to sacrifice historic details like crown moldings, complex baseboards and plaster ceiling medallions at the alter of energy efficiency. Unlike loose fill insulation, spray foam will fill the wall top to bottom and make its way into all the nooks and crannies in the wall’s interior.

Foam insulation is also excellent for insulating and sealing awkward spaces, like the gaps around windows and doors, wall corners, and spaces where materials or phases of construction meet. It can even be used for insulating pipes that are already in place and difficult to access.

Spray foam can also be an excellent choice for attic insulation, especially in older homes and buildings and in hot climates.

Spray foam attic insulation and heating in cold climates

Today’s new cold-climate houses and slope-roofed buildings are constructed with full length ridge and soffit vents for attic ventilation. Ideally, the ceiling of the top floor is heavily insulated, and the attic itself is kept unconditioned. Because of the vents, moisture will not condense on the underside of the roof structure during the winter.

Older buildings often have poorly ventilated roofs and attic floors that are not at all air-tight. When attic insulation is added, warm, moist air can rise into the attic during the winter. When it comes into contact with the cold underside of the roof, it condenses. If there’s too little ventilation and moisture becomes a chronic problem, this can cause the roof structure to rot. However, when both the roof structure and the attic floor are fully sealed with foam insulation, it secures the attic against air, moisture and heat leakage.

Spray foam attic insulation and air conditioning in hot climates

A similar attic insulation method is being used for new construction in hot climates, where air conditioning is needed for most of the year and the roof is seldom colder than the interior. Attics are being left unvented and the roof truss top chords or rafters are being coated with spray foam insulation. This turns the attic into a conditioned space and allows the air conditioning ducts that are often routed through it to stay cool.

Types of spray foam insulation

In general, Polyisocyanurate and Polystyrene foams are both closed-cell and highly effective as insulators and air barriers. However, they also contain VOCs and may be toxic when burned. Icynene spray foam is a healthier and more environmentally friendly product. It is open-cell and is therefore less effective per inch of thickness, and it is less effective as an air barrier. However, it provides excellent soundproofing. Cementitious foam is fireproof, soundproof and non-toxic. However, it is not a good air barrier, and it’s fragile and is therefore not ideal for every installation.

Talk to your HVAC contractor about the best type of spray foam insulation and the best insulation method for your building and your local climate. Spray foam insulation can help keep your heating and air conditioning inside, where it belongs.