Soffit Baffles Protect Your Attic


One of the biggest causes of ice dams are the lack of soffit baffles. What are soffit baffles most people ask? They are also be known as Mor-vents and Sur-vents, usually made of Styrofoam and designed to promote air flow and ventilation of your attic.


With today’s higher insulation requirements, soffit baffles are required by the National and Ontario Building Code. Some builders prefer to install plywood baffles which are nailed to the trusses or rafters allowing air to freely move from soffits past insulation into the attic. What ever the method your attic is required to have a square foot of ventilation for every 300 square feet of attic space. The building code requires a minimum of 25 percent of ventilation from the bottom and a minimum of 25 percent from the top area of the roof.   The remaining 50 percent can be installed at any other locations of the roof.   Most builders in the Orillia and Barrie area just install ventilation on the top and bottom of the roofs. Some complicated roofs with multiple levels have roof vents installed at all locations where there is a variation of heights.


Turbines have become a popular addition to many new homes. The visible spinning seems to assure people that their ventilation performance has been improved. Personally, although turbines do draw out more air than the standard passive roof vent, there are some problems most people are un-aware of.   On the majority of inspections performed in Barrie, Alliston and  Orillia, I have found that turbines allow moisture and snow to accumulate on the insulation in the attic space. Although I have never come across enough snow or moisture to worry about, usually the air movement dries up all moisture before it can become an issue,   I personally would not install turbines on my roof for this reason.  One cure is to lay insulation batts underneath your turbines which will then collect the water and snow and the air movement in attic will then disapate it.  If you have blown insulation the moisture from turbines can compact insulation which will reduce its R-value and eventually leak into ceiling area.


A word of caution, when having your insulation up-graded, always ensure two items.

1. Your insulation installer did not blow insulation into your soffit baffles, causing blockage of air flow.

2. Your insulation installer moved into the different areas of your attic to prevent insulation from blowing over any protruding supports and creating voids or pockets of lower insulation.

Personal choice of blown in insulation is cellulose.  Because cellulose is comprised of recycled paper treated with a fire retardant chemical, mice choose not to nest in cellulose.   Over 95% of brick homes with fiberglass insulation have rodent holes from nesting.