Roofs are sealed systems, but with provision for some air to circulate to prevent the attic getting muggy. Their weakest point is where they overhang the footprint of the building, in order to carry rainwater and snow melt away from the foundations and exterior walls. Soffits protect these soft undersides from the elements. They also play an important role in building insulation, and keeping winter cold outside where it belongs.

How Soffits Came to Get Their Strange Name

The word ‘soffit’ has nothing to do with ‘soft’ at all. In fact, it comes from the French ‘soffite’, meaning formed as a ceiling. This is turn derives from the Latin word ‘suggigere’ meaning to fix underneath something. However to keep things simple, architects call ceilings ‘ceilings’, although we do also find soffits closing in the underside of porch roofs.

How Soffits Protect the Undersides of Eaves

However, most Canadians use the word soffit to refer to the boxing-in of eaves. This attaches to the protruding rafters to form a ceiling between the siding and the edge of the roof line.

In this way, soffits protect the roof structure from the elements, while preventing birds from nesting, or insects entering if properly maintained. They can measure from a few inches to several feet wide depending on the architectural style of the building.

We recommend fitting, or retrofitting soffit vents to prevent condensation inside soffit space due to temperature differences between the attic and the outside air. These are flat grids set in the soffit material to enable attic ventilation. Roof space ventilation is essential in order to:

# Keep the attic cooler and reduce air-conditioning costs in summer

# Prevent heat and moisture buildup in the attic causing mildew and mold

# Prevent condensation settling on rafters and encouraging them to rot

Soffit vents circulate air through attics, maintaining a similar air temperature in soffits and under roofs. This prevents ice damming up over eaves that can cause serious damage to roofing and gutters.

Soffit vents maintain a similar temperature across the entire roof, so snowmelt can flow away smoothly. However they do benefit from regular maintenance.

Soffits protect the soft undersides of roof edges, and that’s important. However, they do need vents to allow air to circulate through roof space. If you have moldy patches on your ceilings, or ice damming on your eaves you have a problem that could develop into something expensive, if not checked. Please give us a call if you need more advice.