Can you Have too Much Insulation in Attic

Insulating your attic is a fantastic way to keep your living space more comfortable and, more importantly, to keep energy bills down. However, when it comes to insulating your attic, more is not always better, and there is such a thing as too much insulation. Call Attic Insulation Toronto for professional attic insulation services in Toronto and the GTA.

How to know if the insulation in your attic is sufficient or too much

The general rule of thumb is that the temperature in your attic should be that of the air right outside, minus the effect of chills and wind. This means that air should be circulating freely up and through your attic. Too much insulation means that your house is practically sealed out and that moisture is getting trapped inside your home. Without sufficient ventilation, the attic may have excessive moisture. You, therefore, want to avoid having insulation material close to the area where your ceiling meets the wall and rafters, blocking these areas could block the free flow of air and provide grounds for mildew and rot to occur. The draft occurring at that space is essential for the health of your attic as well as the quality of the air in your living space. If you visit your attic and find mildew, it is a sign that you have too much insulation.

Batt insulation

If you opt to have batt as your insulating medium, then you are aware that batt has a massive surface area to space ratio. This means that when spread onto your attic’s surface, it insulates your home by diffusing the cold or warm air that would be passing through it, thus creating a thermal barrier. It looks and behaves just like cotton candy; if you placed cotton candy in your mouth, it would shrink to a minimal volume that is barely noticeable. If you force too much batt into your attic, it will not act effectively in slowing down the movement of transient air as it relies on having a huge volume to insulate your attic.


Batt insulation comes in varying R-values depending on the space in question. For example, R-13 is available if you fit batt in a 2-by-4 stud walls room. R-30 fits an area with a 2-by-10 ceiling and floor joist. Some batt manufacturers have variants that will provide satisfactory R-values for smaller spaces. However, stuffing more batt into your attic does not boost its R-value. Ensure that you get the right batt for your volume of space.