Greenhouse Plastic Calculator
Calculate total plastic film sheeting dimensions, bow arc length, hoop requirements, and square footage for poly film or polycarbonate panels.
Structural Sizing Guide: Greenhouse Plastic & Bow Length Calculator
Ordering poly film or polycarbonate sheets for a greenhouse or high tunnel hoop house requires exact mathematical calculations. Purchasing film that is too small leaves your structure exposed, while purchasing excess film wastes money and generates unnecessary plastic scrap. Using our greenhouse plastic calculator (incorporating greenhouse cover calculator, greenhouse bow length calculator, greenhouse hoop calculator, and greenhouse surface area calculator algorithms), you can easily determine precise sheeting dimensions.
Calculating Bow Arc Length for Hoop Houses
For a semi-circular hoop house, the bow arc length ($S$) is calculated using the arch circumference formula:
Arc Length (S) = π × Width / 2 (for perfect semi-circle)
For Gothic arch designs with wall height ($H_w$) and peak height ($H_p$), arc length is estimated by summing sidewall heights and top arc geometry:
📐 Example Gothic Arch Plastic Width:
• Greenhouse Width: 20 ft, Sidewall: 5 ft, Peak: 10.5 ft
• Arc Length over Top ≈ 28.5 ft
• Add 2 ft per side for hip boards / wiggle wire channel attachment = 32.5 ft Plastic Width (Round up to standard 36 ft roll).
Calculating Endwall Plastic Sheeting
Endwalls require separate film cuts. Calculate endwall surface area for two ends ($2 \times \text{Width} \times \text{Peak Height}$) plus an extra 2 feet of overhang for trim and securing along ground boards.