How Hoop House Materials are Estimated
The **Hoop House Calculator** provides a quick estimate for the three key materials: **hoops** (ribs), **purlins** (longitudinal supports), and **poly film** (covering). The formulas use simplified geometry for ease of use.
Key Formulas
$$\text{Hoops Needed} = \lceil \frac{\text{Length}}{\text{Spacing}} \rceil + 1$$ $$\text{Purlin Length} = \text{Length} \times \text{Number of Purlins}$$ $$\text{Film Area} \approx (\text{Length} + 4\text{ ft Flap}) \times (\text{Hoop Arc} + 6\text{ ft Skirt})$$
Material Components
Hoops (Ribs)
These are the curved elements that give the house its shape. The total count includes the initial hoop and the final hoop, plus all those in between based on the spacing.
Poly Film Area
The calculated area is for the roof and sides. It includes essential buffers: $\text{2 ft}$ on each end for tie-downs and $\text{3 ft}$ on each side to create the ground skirt.
Ordering and Planning Tips
- **Film Width:** Poly film is sold in specific roll widths ($\text{24 ft, 32 ft}$, etc.). You must **round up** the "Required Film Roll Width" to the next available size when placing your order.
- **End Walls:** This calculator does not estimate the lumber, film, or doors required for the vertical end walls.
- **Actual Arc Length:** This model uses a semi-circle estimate. For peaked designs (Gothic style), the actual length of the hoop material may be slightly longer.