Hoop House Calculator
Work out greenhouse film size and hoop pipe for a quonset hoop house.
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What this tool does
Work out greenhouse film size and hoop pipe for a quonset hoop house. The arch is modelled as a semicircle on the entered width (classic quonset profile); gothic-arch houses need slightly more film. Film length includes a half-width allowance for one end wall — add more if both ends are film-covered.
How to use the Hoop House Calculator
- Enter or select hoop house width in ft.
- Enter or select hoop house length in ft.
- Enter or select hoop spacing in ft.
- Enter or select extra film tucked at ground (each side) in ft.
- Read the calculated result; change any measurement to compare alternatives.
Formula
arch ≈ half circumference of a semicircle with diameter = width: arc = π × width / 2; film width = arc + 2 × ground allowance; film length = length + width/2 (one end) planning allowance; hoops = floor(length / spacing) + 1
- width
- Hoop house width (ft, before metric conversion)
- length
- Hoop house length (ft, before metric conversion)
- spacing
- Hoop spacing (ft, before metric conversion)
- ground
- Extra film tucked at ground (each side) (ft, before metric conversion)
The arch is modelled as a semicircle on the entered width (classic quonset profile); gothic-arch houses need slightly more film. Film length includes a half-width allowance for one end wall — add more if both ends are film-covered.
Worked example
For hoop house calculator, the following measurements illustrate the exact method: Hoop house width: 12; Hoop house length: 24; Hoop spacing: 4; Extra film tucked at ground (each side): 2.
Inputs
- Hoop house width12 ft
- Hoop house length24 ft
- Hoop spacing4 ft
- Extra film tucked at ground (each side)2 ft
Result
- Film width to buy22.85 ft
- Film length (with one end allowance)30 ft
- Film area685.49 sq ft
- Hoops / bows7
- Total hoop pipe131.95 ft
- Arch length per hoop18.85 ft
Results explained
- Film width to buy
- Film width to buy from the formula above, expressed in ft before metric conversion. The arch is modelled as a semicircle on the entered width (classic quonset profile); gothic-arch houses need slightly more film. Film length includes a half-width allowance for one end wall — add more if both ends are film-covered.
- Film length (with one end allowance)
- Film length (with one end allowance) from the formula above, expressed in ft before metric conversion. The arch is modelled as a semicircle on the entered width (classic quonset profile); gothic-arch houses need slightly more film. Film length includes a half-width allowance for one end wall — add more if both ends are film-covered.
- Film area
- Film area from the formula above, expressed in sqft before metric conversion. The arch is modelled as a semicircle on the entered width (classic quonset profile); gothic-arch houses need slightly more film. Film length includes a half-width allowance for one end wall — add more if both ends are film-covered.
- Hoops / bows
- Hoops / bows from the formula above. The arch is modelled as a semicircle on the entered width (classic quonset profile); gothic-arch houses need slightly more film. Film length includes a half-width allowance for one end wall — add more if both ends are film-covered.
- Total hoop pipe
- Total hoop pipe from the formula above, expressed in ft before metric conversion. The arch is modelled as a semicircle on the entered width (classic quonset profile); gothic-arch houses need slightly more film. Film length includes a half-width allowance for one end wall — add more if both ends are film-covered.
- Arch length per hoop
- Arch length per hoop from the formula above, expressed in ft before metric conversion. The arch is modelled as a semicircle on the entered width (classic quonset profile); gothic-arch houses need slightly more film. Film length includes a half-width allowance for one end wall — add more if both ends are film-covered.
Frequently asked questions
The arch of a 12 ft wide house is about 18.8 ft; with 2 ft tucked at each side you buy roughly 23 ft wide film, and about 30 ft long including one end — around 690 sq ft.
4 ft is common for DIY houses; 5–6 ft works in low-snow areas with strong pipe, and snow-load regions often go tighter (or use a gothic profile that sheds snow).
For a semicircular profile, π × width / 2 — an 18.8 ft pipe for a 12 ft wide house, before adding any straight sidewall height.
6 mil UV-treated greenhouse film is the standard (rated ~4 years). Construction poly from a hardware store lacks UV stabiliser and typically fails within a season.
Yes — end walls need their own material (film, polycarbonate or plywood). The length allowance here covers one film end; framed ends use their own sheet goods.