Soffit and fascia

The two boards that decide whether everything else holds

Fascia and soffit are the parts of a roof people only notice when they are painting. They are also the reason gutters fall off, the reason ridge vents do not work, and the most common way squirrels, rats and wasps get into an attic.

Why they rot here

Water gets behind a gutter and onto the fascia whenever there is no drip edge or gutter apron at the eave, which is true of a great many roofs in this market. Add wind-driven rain that arrives horizontally, humidity that keeps wet wood wet, and termites and carpenter ants that find it, and a painted wood fascia with no metal above it has a predictable life.

Soffit deteriorates for its own reasons: chronic humidity in the overhang, wasp and rodent damage at open corners, and panels that were painted or packed shut until the attic lost its intake. A soffit can be soft on a house with perfectly good gutters.

What wrapping hides

Aluminum wrap over fascia and vinyl soffit panels are a reasonable finish over sound wood: they stop the painting cycle and they hold up well. Installed over wood that is already wet, they are a lid. The wood keeps rotting, invisibly and quickly in this climate, and the first sign is a gutter that comes off the house with a section of fascia still attached to it.

• Ask what is behind the wrap on any house where the trim is already covered. A screwdriver in an inconspicuous spot settles it in seconds.
• Wrap needs a drip edge above it, or water runs down between the metal and the wood, which is the worst of both.
• Vinyl soffit has to be vented where the attic needs intake, and solid panels in the wrong place disable ventilation as effectively as insulation stuffed into the eave.
• Rot at the rafter tail is a different job from rot in the fascia board. If the tails are gone, the fix is structural carpentry and it is worth knowing that before the trim goes back on.

The ventilation half of the job

Attic ventilation is an intake-and-exhaust pair. Ridge vent is the exhaust; vented soffit is almost always the intake. A roof with a continuous ridge vent and blocked soffits pulls its make-up air out of the house instead, which in a nine-month cooling season means pulling conditioned air into the attic and humid outside air into the house. How attic ventilation works.

1. Find out whether there is intake at all

   Some houses here never had vented soffit. Others have it, painted shut, or blocked from above by insulation pushed into the eave.

2. Open the path

   Vented panel, and baffles at the eave so insulation cannot slide back into the airway. This is usually the cheapest meaningful improvement available on an older roof.

3. Match exhaust to intake

   More exhaust than intake is not better. It just pulls air from the easiest available place, which is the house.

4. Check it from inside

   From the attic you should be able to see daylight at the eaves. Damp sheathing, rusty nail points, or ductwork sweating in a still attic all say the same thing: the air is not moving and the moisture has nowhere to go.

Animals and insects

A soft fascia board or an open soffit corner is an invitation. Squirrels and rats widen a gap into an entrance, wasps build in an open overhang, and termites and carpenter ants are attracted to precisely the wet wood a failed gutter produces. The order of operations matters: the animals come out first, then the hole gets closed. Closing it first traps them inside the overhang, which becomes a worse problem than the one you started with.