Tips For Insulating Your Attic
November 30, 2011Keywords Meta-Tag
One of the easiest ways to improve the energy efficiency of your house is to insulate the attic. Many materials exist today that offer better performance than traditional fibreglass batting. While many of us tend to only consider the ‘R’ or insulation values of insulation, newer forms of insulation such as spray polyurethane form (SPF) also work to control water damage and make the maintenance of our roofs a little easier.
Today’s North American residential construction field uses two types of spray polyurethane foam (SPF): the closed-cell, medium-density SPF (also known as “2 pounds”, which expands to 2 pounds per square inch), and the open-cell, low-density SPF (known as ‘half pound’ for the same reason). With proper installation, both expand to fill voids and create an air seal in your attic, however the closed-cell SPF has better insulation values as a result of its higher thermal resistance and lower vapour permeance.
In an unvented roof assembly (a typical roof design for most houses built in the last couple of decades), ccSPF works to regulate the interior temperature of your home- repelling exterior warm, moist air in warmer climates and preventing that same warm air from escaping your home in colder seasons. With almost doublethe insulation value compared to other forms of insulation- including fibreglass batts and blown cellulose- ccSPF offers greater thermal performance.
Yet ccSPF does more than just regulate air temperature when installed in your attic. Vapour diffusion- the rate at which moisture passes through building materials (a natural phenomenon)- is also controlled by ccSPF. As water vapour moves through the foam, the insulation works to resist and reduce this vapour, such that by the time the vapour reaches the back of the insulation and roof sheathing, there is not enough of it remaining to cause condensation problems.
This water absorption function of ccSPF is also added insurance against rainwater damage. Should your roofing materials get damaged and starting leaking, the waterproofing characteristics of the foam work to contain the leak to the area immediately adjacent to the hole, preventing the spread of water damage and making it easier to identify and repair.
With the many benefits of newer forms of insulation available today, why not go with an insulation that does more than insulates?