How do I calculate how much soffit I need?

Measure the linear feet of your roof eaves (the horizontal distance where soffit will be installed), then multiply by the overhang width in feet. This gives square footage. Divide by your soffit panel size (typically 12" × 12' = 12 sq ft per panel for aluminum, 16" × 12' = 16 sq ft for vinyl). Add 10% for waste and cuts.

What is the difference between soffit and fascia?

Soffit is the horizontal material that covers the underside of your roof overhang (eave), providing ventilation and protecting rafters. Fascia is the vertical board that runs along the roof edge, covering rafter tails and supporting gutters. Both work together to protect your roof system and provide a finished appearance.

How much does soffit and fascia cost per linear foot?

Soffit materials cost $1-6 per square foot: aluminum vented $1.50-2.50/sf, vinyl $1-2/sf, fiber cement $3-5/sf, and wood $4-8/sf. Fascia costs $2-8 per linear foot: aluminum $2-4/lf, vinyl $1.50-3/lf, PVC $3-5/lf, wood $2-4/lf. Professional installation adds $3-8 per linear foot.

Should soffit be vented or solid?

Vented soffit is recommended for most homes to provide attic ventilation, reducing heat buildup and moisture. Use vented soffit along eaves where air can enter, paired with ridge or gable vents for exhaust. Solid soffit is used in areas that don't need ventilation, like porch ceilings, or combined with continuous ridge vents using intake venting ratios.

How wide should fascia boards be?

Fascia board width depends on your rafter tail depth - typically 4", 6", or 8". Measure from the top of the rafter to where you want the bottom of the fascia. Common sizes: 1×4 for smaller overhangs, 1×6 for standard residential (most common), 1×8 or 1×10 for larger custom homes. Add 1-2" for overlap behind gutters.

What is the best material for soffit in coastal areas?

For coastal South Carolina, aluminum and vinyl soffit are best due to salt air resistance. Aluminum vented soffit is most popular - it won't rot, rust, or corrode, provides excellent ventilation, and lasts 30+ years. Vinyl is more affordable but may fade faster. Avoid wood soffit near the coast as salt and humidity accelerate rot.

How many soffit panels do I need for a 2000 sq ft house?

A 2,000 sq ft home typically has 150-250 linear feet of eaves with 12-24 inch overhangs. Example: 200 linear feet × 16" overhang = 267 sq ft of soffit. Using 12 sq ft aluminum panels, you'd need 25-30 panels with waste. Our calculator provides exact counts based on your specific measurements and chosen material.

Do I need F-channel or J-channel for soffit installation?

F-channel mounts on the fascia board and holds the outer edge of soffit panels. J-channel mounts on the wall and holds the inner edge. You need both for proper installation. Calculate F-channel by total eave length, and J-channel by the same measurement. Both come in 12-foot lengths.

Soffit & Fascia Calculator

Calculate soffit panels, fascia boards, and trim accessories for your roof overhangs. Get instant material quantities and cost estimates.

All Materials

Accessories Included

Coast-Rated Options

1Soffit Material

Cost-effective perforated vinyl panels

Vented12 sq ft/panel

2Fascia Material

Pre-formed aluminum wrap for existing wood

10' lengthsWidths: 4", "5", "6", "8", "10", "12

3Eave & Rake Measurements

Measure each eave and rake section where you'll install soffit and fascia.

Section Name

Length (ft)

Overhang (in)

Fascia Height (in)

Section Name

Length (ft)

Overhang (in)

Fascia Height (in)

Section Name

Length (ft)

Overhang (in)

Fascia Height (in)

Section Name

Length (ft)

Overhang (in)

Fascia Height (in)

Waste Factor

Include F-Channel (at wall)

Include J-Channel (at fascia)

Understanding Soffit & Fascia

What is Soffit?

Soffit is the material covering the underside of your roof overhang (eave). It protects rafters from weather and provides ventilation to your attic when vented panels are used.

✓Vented soffit provides critical attic airflow
✓Prevents moisture buildup and mold
✓Keeps pests out of your attic

What is Fascia?

Fascia is the vertical board running along the roof edge, attached to rafter ends. It supports the bottom row of shingles and holds your gutter system.

✓Supports gutter installation
✓Protects rafter ends from water damage
✓Provides finished appearance to roofline

Soffit Material Comparison

Material	Lifespan	Maintenance	Coastal Rating	Cost
Aluminum	30-40 yrs	Low	⭐⭐⭐⭐⭐	$$$
Vinyl	20-30 yrs	Very Low	⭐⭐⭐⭐	$$
Fiber Cement	40-50 yrs	Low	⭐⭐⭐⭐⭐	$$$$
PVC/Cellular	30-40 yrs	Very Low	⭐⭐⭐⭐⭐	$$$$
Wood	15-25 yrs	High	⭐⭐	$$$

Coastal South Carolina Recommendation

For Myrtle Beach and coastal areas, we recommend aluminum or PVC materials with stainless steel or aluminum fasteners. Salt air rapidly corrodes standard steel nails and can cause premature failure of wood products.

Frequently Asked Questions

How much soffit and fascia do I need for my house?

Measure the linear feet around all eaves and rakes of your roof. Multiply the linear feet by the overhang width (in feet) to get soffit square footage. For fascia, use the total linear feet multiplied by the board width. Add 10-15% for waste.

Do I need vented or solid soffit?

Most homes need vented soffit for attic ventilation, typically with 1 sq ft of Net Free Area (NFA) per 150 sq ft of attic space. Use solid soffit only for enclosed porches, covered patios, or areas where you don't want airflow into the attic.

What is the best soffit material for coastal areas?

For coastal South Carolina, aluminum and PVC/cellular materials perform best. They resist salt air corrosion, humidity, and won't rot like wood. Always use stainless steel or aluminum fasteners to prevent rust staining.

How much does soffit and fascia installation cost?

Total installed cost ranges from $6-15 per linear foot depending on materials. Vinyl is most affordable at $6-9/lf, aluminum costs $8-12/lf, and fiber cement or PVC runs $10-15/lf. This includes materials, labor, and disposal of old material.

What is the difference between F-channel and J-channel?

F-channel mounts at the wall to receive soffit panels and has a nail flange. J-channel is used at the fascia edge where soffit panels terminate. Both are essential trim pieces for a professional soffit installation.

Can I install soffit over existing soffit?

Yes, if the existing soffit is flat and in good condition. However, we often recommend removal to inspect for rot, ensure proper ventilation, and achieve a cleaner finish. Removal adds minimal cost and prevents hidden problems.

How wide should soffit overhang be?

Standard residential soffit overhang is 12-16 inches. Wider overhangs (18-24 inches) provide better shade and weather protection but require more materials. Your existing rafter tails determine the maximum overhang width.

What size fascia board do I need?

Fascia size depends on your rafter dimensions. Most homes use 6" or 8" fascia. Measure from the bottom of the roof decking to the bottom of the existing fascia (or rafter tail) to determine the correct height.