What, Where and When to Insulate

There is a lot to know when it comes to properly insulating a home. While we can't cover every single situation, we can still provide you with some good basic information to get you started.

What to Insulate

The building code states that you must insulate all exterior walls including basements and crawlspaces, ceilings including attics, cathedrals, or vaulted areas, and rim joists. It is optional to insulate crawlspace floors or floor joist areas separating different levels. It is however a good practice to insulate all floor joists to prevent cold feet and eliminate noise from above or below.

Where to Insulate

The building code states insulation must be installed on the warm side of the building. There is however a growing trend to insulate on the exterior of a wall assembly. Make sure to discuss this with your local building department before doing so to make sure your proposed ratios of interior to exterior insulation are correct.

Insulation should be installed between heated and unheated spaces, between heated spaces and the exterior, on the inside or outside of foundation walls, around perimeter of slab-on-ground below adjacent finished ground level. Insulation should create a single, continuous envelope around your home. For more information, view this illustration of locations requiring insulation.

When to Insulate

With new construction, insulation is installed after all plumbing and electrical inspections have been passed. Don't wait until your inspections are complete to request a quote. Quotations should be obtained as far in advance as possible, don't leave the decision to insulate until the last minute. Especially if it's later in the year. You will want to take into consideration possible wait times in busy seasons like Fall and Winter.

There is no best time to insulate. Many people wait until the weather gets colder because they are worried about heat loss, but it's just as important to insulate during the hotter months to save money on air conditioning and the strain put on cooling equipment.

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