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Calculate soffit panels, fascia boards, J-channel, venting requirements, and accessories for your eave project. Get accurate material estimates for professional exterior finishing.
Total linear feet around the roof edge
For ventilation requirements (1 sq ft vent per 150 sq ft attic)
Enter perimeter to calculate soffit requirements.
Enter perimeter to calculate fascia requirements.
Enter perimeter to calculate accessories.
| Material | Cost Range | Lifespan | Maintenance | Best For |
|---|---|---|---|---|
| Vinyl | $1-3/sq ft | 20-30 years | Very Low | Budget projects, DIY |
| Aluminum | $3-6/sq ft | 30-40 years | Low | Durability, all climates |
| Wood (Cedar/Pine) | $4-8/sq ft | 15-25 years | High | Historic homes, aesthetics |
| Fiber Cement | $5-10/sq ft | 40-50 years | Low-Medium | Fire resistance, durability |
| Composite/PVC | $6-12/sq ft | 50+ years | Very Low | Premium projects, rot-free |
Standard vinyl/aluminum panels cover 12 sq ft per 12" × 12' panel.
Standard fascia boards come in 12-foot lengths.
J-channel runs along both the wall and fascia edges of soffit.
NFA = Net Free Area. Building codes require 1:150 ratio (1 sq ft vent per 150 sq ft attic).
Soffit is the horizontal underside material that covers the area between the exterior wall and the roof edge (the overhang). Fascia is the vertical board that runs along the roof edge, covering the ends of the rafters. Together, they protect the roof structure from weather and pests while providing a finished appearance.
In most cases, vented soffit is recommended because proper attic ventilation prevents moisture buildup, ice dams, and extends shingle life. The 1:150 rule requires 1 sq ft of ventilation per 150 sq ft of attic space. However, solid soffit may be used in specific areas like porch ceilings or where additional vents (like separate intake vents) are installed.
J-channel creates a track that holds soffit panels in place along their edges - you typically need it along both the wall and fascia edges. F-channel serves a similar purpose but has a different profile that allows it to receive both the soffit panel edge and the drip edge. The "J" and "F" refer to the cross-sectional shape of the channels.
You can install aluminum or vinyl fascia wrap over existing wood fascia only if the wood is in good condition - solid, not rotted, and properly secured. However, installing over damaged or rotted wood will trap moisture and accelerate decay. It's best to replace any compromised wood before covering with new material.
Standard residential overhang depths range from 12 to 24 inches. A 12-inch overhang is common for newer construction, while older homes may have 18-24 inch overhangs. Larger overhangs provide more protection from rain and sun but require more soffit material. Very deep overhangs (36+ inches) may need additional support.
Proper attic ventilation serves multiple purposes: it removes excess heat in summer (reducing cooling costs), prevents moisture buildup that can cause mold and rot, prevents ice dams in winter by keeping the roof deck cold, and extends shingle life by reducing temperature extremes. Soffit vents provide intake while ridge or roof vents provide exhaust, creating natural airflow.