Roof Tarp Calculator

Calculate the right tarp size, anchoring materials, and cost for emergency storm damage temporary roof repair

Calculate tarp size needed based on damaged area and overlap requirements

Quick presets

feet
feet

Safety Equipment

8 roof anchors

1-story • 10 ft height • 155 ft perimeter

PRO

Professional Calculator

Extended parameters for precise calculations

sq ft

Estimated Materials

60 bundles

Roof Area

1,792 sq ft

Squares

17.9

Detailed Breakdown

Roof Area1,792 sq ft
With Waste1,971 sq ft
Roofing Squares17.9
Bundles60
How to Use This Calculator
The Roof Tarp Calculator helps you determine the right tarp size, anchoring materials, and cost for an emergency temporary roof repair after storm damage, fallen tree limbs, or other sudden roof failures.

Tarp Sizing tab: Enter the width and length of the damaged area on your roof. The calculator adds your selected overlap distance (4 feet is standard) to all sides and accounts for ridge coverage if the damage is near the peak. If the tarp needs to go over the ridge, the calculator adds the ridge extension distance to the total length. The output is the minimum tarp dimensions you need. Round up to the nearest standard tarp size — common sizes are 10x12, 12x16, 16x20, 20x30, 20x40, and 30x50 feet. Always buy a tarp larger than the calculated minimum because you can fold excess material under the nailer boards, but a tarp that falls short leaves exposed damage.

Materials tab: Enter the tarp dimensions from the previous tab and select your tarp type and anchoring method. Standard blue poly tarps are cheapest but last only 30-60 days before UV exposure makes them brittle. Heavy-duty UV-treated tarps cost 2-3 times more but last 6-12 months — essential if your permanent repair will be delayed. The anchoring method determines whether you need 2x4 nailer boards and screws (most secure), sandbags (no roof penetration), or a combination. The calculator tallies the linear feet of 2x4 lumber, number of screws, and sandbag count based on your tarp perimeter and the spacing you select. In hurricane zones, use 1-foot nailer spacing and additional cross-strapping.

Cost tab: Select the standard tarp size closest to your needs, tarp type, and whether you are doing the work yourself or hiring an emergency roofer. DIY is feasible on single-story homes with a moderate pitch and dry conditions — never climb a wet or steep roof during active weather. Emergency roofer rates range from $500-$1,500 depending on roof accessibility, damage severity, and post-storm demand in your area. The calculator provides a total project cost including tarp, lumber, screws, sealant, and labor. Keep all receipts and photos — homeowner insurance covers emergency tarping under the duty-to-mitigate provision in virtually all standard policies.

The Formula
The roof tarp calculator uses these formulas:

Required Tarp Width = Damage Width + (2 × Overlap Distance) Example: 10 ft damage + (2 × 4 ft) = 18 ft → round up to 20 ft standard

Required Tarp Length = Damage Length + Overlap at Eave + Overlap at Top + Ridge Extension (if applicable) Example: 12 ft + 4 ft + 4 ft + 4 ft ridge = 24 ft → round up to 30 ft standard

Tarp Perimeter = 2 × (Tarp Width + Tarp Length) Example: 2 × (20 + 30) = 100 linear feet of edge to anchor

2x4 Nailer Board Length = Tarp Perimeter (boards placed along all edges) Example: 100 LF → 13 pieces of 8-ft 2x4 lumber

Screw Count = Tarp Perimeter / Screw Spacing × 12 (converting feet to inches) Example at 16" spacing: (100 × 12) / 16 = 75 screws

Sandbag Count = Tarp Perimeter / Sandbag Spacing Example at 3 ft spacing: 100 / 3 = 34 sandbags

Material Cost = Tarp + Lumber + Screws + Sealant Example: $60 tarp + $52 lumber (13 × $4) + $15 screws (box of 100) + $8 sealant = $135

Total Cost with Labor = Material Cost + Emergency Labor Example: $135 + $650 (emergency roofer) = $785
Example Calculation
Example: Tree Branch Through Roof — Emergency Tarping in Georgia After Thunderstorm

A large oak branch punched through James's roof in Atlanta during a severe thunderstorm, creating a 10-by-12-foot area of damage on the back slope near the ridge. Rain is expected again tomorrow.

Step 1: Tarp Sizing
• Damaged area: 10 ft wide × 12 ft along slope
• Overlap: 4 ft on all sides (standard)
• Ridge coverage: Yes — damage is within 3 ft of ridge
• Ridge extension: 4 ft down the other side
• Required tarp width: 10 + 4 + 4 = 18 ft
• Required tarp length: 12 + 4 (eave overlap) + 4 (ridge) + 4 (over-ridge) = 24 ft
• Nearest standard size: 20 × 30 ft

Step 2: Materials List
• Tarp: 1× heavy-duty UV poly 20x30 = $65
• Anchoring: 2x4 nailer boards along all edges - Tarp perimeter: 2 × (20 + 30) = 100 linear feet - 2x4 boards: 13 pieces × 8 ft at $4 each = $52 - 3" deck screws: 75 screws (1 box of 100) = $12
• Sealant: 1 tube polyurethane for screw heads = $8
• Total materials: $137

Step 3: Cost with Emergency Roofer
• Emergency roofer rate in Georgia: $600 for single-story, 2-hour job
• Materials: $137
• Labor: $600
• Total emergency tarping cost: $737

Insurance: James's homeowner policy covers this as a mitigation expense. He takes photos of the damage before and after tarping, saves all receipts, and files the $737 as part of his storm damage claim. The permanent roof repair — replacing the damaged decking and shingles — will cost an additional $2,500-$4,000 once the adjuster inspects and approves. The tarp will protect the interior for 6-12 months while repairs are scheduled.

Frequently Asked Questions

How big should a roof tarp be to cover storm damage?
A roof tarp must extend at least 4 feet beyond the damaged area on all sides and should go over the ridge and at least 4 feet down the other side if the damage is anywhere near the ridge line. For a 10-by-12-foot area of damage with ridge coverage, you need a tarp at least 18 feet wide (10 + 4 + 4) and at least 24 feet long (12 + 4 overlap at eave + 4 overlap at top + 4 over-ridge extension). The nearest standard tarp size would be 20x30 feet. Always round up to the next standard size — extra material can be folded under nailer boards, but a tarp that is too small will allow water intrusion at the edges. Standard tarp sizes available at home improvement stores include 10x12, 12x16, 16x20, 20x30, 20x40, and 30x50.
How do you properly anchor a tarp to a damaged roof?
The most secure method uses 2x4 nailer boards screwed through the tarp into the roof deck. Place a 2x4 along each edge of the tarp, wrap the tarp edge over the board, and drive 3-inch deck screws through the board and tarp into the roof sheathing every 12-16 inches. This sandwiches the tarp between the board and the roof surface, preventing wind from getting underneath. At the ridge, wrap the tarp over and secure with a nailer on the opposite side. At the eave, the tarp should extend past the fascia and be weighted or nailed to a fascia-mounted board. In areas where you cannot or do not want to penetrate the roof further, use sandbags (40-60 lbs each) placed every 3-4 feet along the tarp edges. A combination approach — nailers at the top and sides, sandbags at the eave — works well for most situations.
How much does emergency roof tarping cost in 2026?
Emergency roof tarping costs range from $50-$150 for DIY materials only to $500-$1,500 for professional installation in 2026. A typical emergency roofer charges $500-$800 for a single-tarp job on a single-story home and $800-$1,500 for a two-story home or large damage area. After major storms like hurricanes or tornadoes, prices can spike to $1,500-$2,500+ due to high demand and limited contractor availability. The material cost for a heavy-duty 20x30 tarp, 2x4 nailers, and screws is approximately $80-$130. Shrink-wrap systems cost more at $2-$4 per square foot installed but last 12-24 months versus 30-90 days for standard tarps. Most homeowner insurance policies cover emergency tarping as part of the duty to mitigate further damage, so keep all receipts and take before-and-after photos.
Will homeowner insurance pay for emergency roof tarping?
Yes, in almost all cases. Standard homeowner insurance policies include a "duty to mitigate" clause that requires you to take reasonable steps to prevent further damage after a covered event — and the insurer reimburses you for those costs. Emergency tarping is the textbook example of a mitigation expense. To ensure reimbursement, document the damage with dated photos before tarping, save all receipts for materials and labor, get a written invoice from any contractor, and file the tarping cost as part of your overall claim. Most policies cover $500-$3,000 for temporary repairs without a separate deductible. Do not wait for an adjuster visit before tarping — the insurer expects you to protect the home immediately. However, do not make permanent repairs until the adjuster has inspected, as this can complicate the claim.
How long can a roof tarp stay on before permanent repair?
Standard blue poly tarps last 30-60 days before UV degradation causes tearing and leaking. Heavy-duty UV-treated poly tarps last 6-12 months. Silver UV-reflective tarps also last 6-12 months. Professional shrink-wrap systems can last 12-24 months. After a major storm event, permanent repair may be delayed weeks or months due to contractor backlogs and insurance adjuster scheduling — in 2026, post-hurricane wait times in Florida and Texas can exceed 3-6 months. For waits longer than 60 days, invest in a heavy-duty UV tarp or shrink-wrap rather than a cheap blue tarp. Check tarped areas weekly for loosening, tearing, or pooling water. Re-secure or replace tarps promptly if they show wear. Some municipalities have ordinances requiring permanent repair within 90-180 days of a temporary cover, so check local codes.

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