Material Summary
- Soffit material—
- Style—
- Coverage area (with waste)— sq ft
- Boxes to buy— boxes
- Required intake ventilation—
- Estimated cost—
Soffit Material Chart
| Material | Notes |
|---|---|
| Vinyl | Cheapest, light, easy DIY, comes vented or solid, can sag in heat |
| Aluminum | Durable, rust-proof, holds paint, slightly pricier than vinyl |
| Wood | Traditional look, paintable, needs upkeep and can rot if unvented |
| Fiber cement | Very durable, fire and rot resistant, heavier and costlier |
Vented vs Solid Soffit
| Style | Use |
|---|---|
| Fully vented | Maximum intake airflow; common on long eaves feeding a ridge vent |
| Center-vented | A vented strip down the middle of a solid panel; moderate airflow |
| Solid | No airflow; used where venting is handled elsewhere or not needed |
How Much Soffit Do I Need?
Soffit is the material that closes the underside of the roof overhang, running along the eaves between the fascia and the wall. To size it, multiply the eave length by the overhang depth to get the area, add any rake, porch, and dormer soffits, then add a waste factor and divide by the coverage of one box or carton. This calculator returns the boxes to buy and the cost, and because soffit is also where attic air comes in, it checks whether you need vented soffit for proper ventilation.
Soffit vs Fascia
These two eave parts work together but are different. The fascia is the vertical board facing outward at the edge of the roof, where the gutter mounts. The soffit is the horizontal panel underneath it, bridging the gap from the fascia back to the wall and hiding the rafter tails. Fascia takes the weather and carries the gutter; soffit closes the overhang and, when vented, lets the attic breathe. You usually install drip edge and fascia first, then tuck the soffit in behind the fascia.
Vented Soffit and Attic Airflow
A healthy attic needs air moving through it, drawn in low at the soffits and pushed out high at the ridge. Vented soffit is the intake half of that system: the small slots or perforations let outside air enter, flow up the underside of the roof deck, and exit through ridge or gable vents, carrying away heat and moisture that would otherwise rot framing and shorten shingle life. As a rule of thumb, provide one square foot of net free vent area per 150 square feet of attic floor, balanced between intake and exhaust. Solid soffit blocks that airflow, so use vented soffit unless the attic is ventilated some other way.
Frequently Asked Questions
Do I need vented or solid soffit? Use vented soffit if it serves an attic that needs intake air, which is most homes; solid is for porches or where venting is handled elsewhere.
How is soffit sold? In boxes or cartons of panels rated for a certain coverage in square feet; divide your area by that to get boxes.
How wide is soffit? It spans the overhang depth, commonly 12 to 24 inches; panels are cut to that width.
Can I mix vented and solid? Yes, many homes run vented along the eaves and solid under porches or gable ends.