If the attic is obstructed and an irregular shape, blownin fibreglass or cellulose may be the best option, as the loose material can fill around obstructions and provide a continuous blanket of insulation. Blown-in insulation can also be combined with batt insulation, with the loose fill above the batt insulation. Ensure that no insulation gets blown into the soffit vent area or comes in contact with heat-generating fixtures or chimneys. See the previous air sealing procedures which allow for insulation guards.

If the attic is a simple shape with joists spaced regularly at 16" or 24", fibreglass or mineral wool batt insulation may be a good alternative to blown-in insulation. Be sure to install the insulation with a snug fit but without compressing the insulation. In general, be sure to follow the manufacturers' directions when installing all types of insulation to achieve optimal results.

Both blown-in and batt insulation can be combined with spray foam in the attic space in a flash-and-fill application. See the Guide entitled BC Housing - Best Practices - Flash-and-Fill Insulation. Additional information about insulation can be found from product manufacturers and in Insulation: A Guide for Contractors to Share with Homeowners, part of the U.S. Department of Energy's Building America Best Practices Series (see Resources).