Soffit and Fascia Explained: Where They Sit and What They Do

Soffit and fascia are the two finishing parts at the edge of your roof. Fascia is the vertical board along the roof edge that carries the eavestrough. Soffit is the panel on the underside of the overhang, between the fascia and the wall. Fascia shields the rafter ends from water, and vented soffit lets fresh air into the attic.

What is fascia on a house?

Fascia is the long board that runs along the ends of the rafters at the edge of the roof. It is the flat, vertical band you see when you look up at the roofline from the street. It does three jobs:

• It closes off the rafter ends so water, wind and pests cannot reach the framing.
• It carries the eavestrough. Hidden hangers are screwed through the fascia into solid wood, typically every 60 cm (24 inches) or closer where snow and ice load is heavy.
• It gives the roof edge a finished look.

Fascia comes as wood, wood wrapped in custom-bent aluminum, pre-formed aluminum or vinyl. The sloped edges of a gable end have matching trim, usually called rake trim. Fascia rot usually starts where an eavestrough has overflowed or leaked, or where ice has sat against the board.

What is soffit on a house?

Soffit is the underside of the roof overhang. It is the horizontal surface you see when you stand under the eave and look up. It runs from the back of the fascia to the wall of the house and covers the ends of the rafters.

Soffit panels are made of aluminum, vinyl or wood, and some are board-and-batten style. They come in two kinds. Vented soffit has slots or perforations that let air through. Solid soffit has none. Soffit does two jobs. It closes the eave so squirrels, raccoons, birds and wasps cannot get into the attic, and vented soffit is the air intake half of attic ventilation. Damaged or loose panels let animals in and block that airflow.

Soffit vs fascia: the differences side by side

Soffit and fascia vs eaves, flashing and eavestroughs

These words get mixed up because they all sit near the edge of the roof.

• Eaves are the lower edges of the roof that overhang the walls. Soffit and fascia are the finished parts of the eaves.
• Eavestroughs are the troughs hung on the fascia that carry roof water to the downspouts.
• Drip edge is a thin metal strip along the roof edge that guides water off the roofing and into the trough.
• Flashing is metal or membrane that seals the joints where the roof meets a wall, chimney, valley or pipe.

Fascia and flashing both deal with water, but they are different parts. Fascia is a board that finishes the roof edge. Flashing is a waterproofing layer at a joint. A quote for fascia does not include flashing, and the reverse is also true.

Is soffit and fascia part of the roof? They are part of the roofline: they attach to the roof framing and work with the roof and the eavestrough. They are usually described as exterior trim rather than roofing, and a roofer or an exterior contractor may do the work. Quotes and inspection reports group them differently, so check what each document covers.

What soffit and fascia do for ventilation and water control

Water. The eavestrough hangs on the fascia. If it overflows, or ice sits behind it, water reaches the board and the rafter ends. Once the fascia is soft, the hangers pull out and the trough sags. Together, soffit and fascia seal the eave so wind-driven rain and snow stay out of the attic.

Ventilation. Air enters through vented soffit and leaves through ridge or roof vents, carrying moisture with it. Natural Resources Canada suggests that about half of an attic's ventilation openings be continuous soffit vents, with the rest at the gable, ridge or roof. Insulation stuffed against the soffit blocks that path. Baffles in each rafter space keep it open.

Ice dams. Soffit does not cause them. Heat leaking from the house into the attic does. Poor intake, though, feeds attic moisture, mould and ice dams. The soffit ventilation guide explains how to check the airflow path.

Signs your soffit and fascia need repair

Walk around the house and look up. Check for:

• Peeling or bubbling paint on the fascia.
• Soft, dark or crumbling wood.
• An eavestrough that sags or pulls away from the house.
• Gaps, sagging or missing soffit panels.
• Wasps, birds or squirrels going in and out at the roofline.
• Stains, mould or damp insulation in the attic near the eaves.

In Ontario, freeze-thaw cycles and ice sitting against the board, plus overflow from eavestroughs clogged with leaves each fall, are the usual causes of damage. Rotted fascia should be replaced before anything new goes over it, because wrapping over rot hides the problem. The fascia replacement signs guide goes into more detail.

Reading a soffit and fascia quote

Once you know the parts, a quote is easier to read. Look for these terms and questions:

• Replace or wrap. Wrapping covers sound wood with aluminum. Rotted boards should be replaced first.
• Vented or solid soffit. Ask which panels are vented and how intake stays clear of insulation.
• Eavestrough work. Are the troughs removed and rehung, or replaced? Soffit, fascia and eavestroughs are often done together and colour-matched.
• Hidden damage. How is rotted wood priced once the old trim is off?

The soffit and fascia replacement cost guide lists the factors behind the price. D&D Exterior Finishing handles soffit installation and replacement and fascia repair and installation, with a free written estimate before work starts.

Soffit and fascia questions homeowners ask

Is soffit and fascia the same thing?

No. Fascia is the vertical board at the roof edge that carries the eavestrough. Soffit is the horizontal panel under the overhang, between the fascia and the wall. They meet at the edge of the roof and are often replaced together, but they are different parts with different jobs.

Is soffit and fascia part of the roof?

They are part of the roofline. They attach to the roof framing and work with the roof and eavestrough, but most people call them exterior trim. Roofers and exterior contractors both install them. Check what a quote or inspection report includes, because they may be grouped under roofing or trim.

What is the difference between fascia and flashing?

Fascia is a board along the roof edge that finishes the rafter ends and holds the eavestrough. Flashing is thin metal or membrane that seals joints where the roof meets a wall, chimney, valley or pipe. Both help keep water out, but they are separate items on a quote.

What is the difference between soffit, fascia and eaves?

The eaves are the lower edges of the roof that overhang the walls. Fascia is the board across the end of the eaves, and soffit is the panel on the underside. The eavestrough hangs on the fascia. Together they finish the roof edge and, with vented soffit, supply attic air.

Devon Moore, Operations Lead Co-Founder & Operations Lead — D&D Exterior Finishing

Devon Moore is the co-founder and Operations Lead at D&D Exterior Finishing, specializing in siding, roofing, windows, and exterior renovations across Waterloo Region.