Greenhouse & Shade Net Calculator & Covering Area & Cost
Covers polyhouses
Size your greenhouse film or shade net — from the structure's dimensions get the covering area for roof, gable ends and walls, with an overlap allowance and cost.
Enter your structure
Next: add a little extra beyond the 10% overlap for fixing into channels and future repairs, and choose your covering by purpose — a UV-stabilised polyfilm for a warm greenhouse, or a shade-net of the right shade % (35–75%) to cut heat for nurseries and sensitive crops.
Roof slope width = √((width/2)² + rise²); gable ends (two triangles) = width × rise. Order a roll width that minimises seams.
Greenhouse cover — key facts
- Roof slope width
- √((W/2)² + rise²)
- Gable ends
- width × rise
- Walls
- 2 × (L + W) × height
- Overlap
- ≈ 10–15%
- Film thickness
- 150–200 micron
- Film life
- ≈ 3–4 years
- Shade net life
- ≈ 5–7 years
- Privacy
- Runs in your browser; nothing uploaded
Buy the right amount of film or net
Covering material is one of the biggest costs in a protected-cultivation structure, and the surface area is easy to under-estimate because the sloped roof is larger than the floor it covers. Get it wrong and you either run short mid-job or over-spend on expensive UV film. The area is pure geometry — two roof slopes, two triangular gable ends, and the side walls — plus an overlap for fixing the sheet into trenches and joints.
This tool computes the full covering area for film or shade net, breaks it into roof, gable ends and walls, adds your overlap allowance, and costs it. Toggle side covering to compare a fully-clad greenhouse against a roof-only shade structure. Use thicker, UV-stabilised film for longer life, fix it firmly against wind, and re-estimate at each re-cover. Pair with the Land Area and Crop Profit tools to plan the structure's economics.
Order accurately
Get the true sloped-roof area, not just the floor footprint.
Budget the cover
Add a price per m² to see the film or net cost up front.
Compare designs
Toggle side cladding to weigh a closed house vs a shade structure.
Plan re-covers
Re-estimate the area each time film reaches end of life.
Frequently Asked Questions
How much covering material does my greenhouse need?+
Add the roof area, the two triangular gable ends, and (if covered) the side and end walls, then add an overlap allowance for fixing. The roof is two slopes, each √((width/2)² + rise²) wide × the length. This tool sums it all and adds your overlap percentage to give the quantity to order.
How much shade net do I need?+
The same geometry applies: net the roof and, if required, the sides. A flat-top shade structure simply needs length × width for the roof plus 2 × (length + width) × height for the sides. Enter your dimensions and turn side covering on or off; the tool gives the net area plus overlap for tying.
How big should the overlap allowance be?+
Allow about 10–15% extra over the bare surface area for fixing, tucking into ground trenches, joining sheets and future repairs. The tool defaults to 10%; increase it for windy sites or where film is buried/clamped along edges.
What shade percentage net should I choose?+
Shade nets come in grades (e.g. 35%, 50%, 75%, 90%). Leafy greens and nurseries often use 50%; flowers and shade-loving crops 50–75%; very hot regions or delicate crops up to 75–90%. This tool sizes the area; pick the shade % for your crop and climate separately.
How do I measure roof rise?+
Roof rise is the vertical height from the top of the side wall up to the ridge (the peak). For a flat-topped shade structure it's zero; for a gable greenhouse it's the gable height. The bigger the rise, the larger the roof area, because the slopes get longer.
Should I cover the sides?+
Greenhouses are usually fully clad (roof + gable ends + side walls) for climate control; shade structures are often roof-only or roof-plus-partial-sides for airflow. Toggle side covering in the tool to compare both, since the walls can be a big share of the total area.
How long does greenhouse film last?+
UV-stabilised polyhouse film typically lasts 3–4 years (some premium films 5+), shade nets 5–7 years, depending on sunlight, dust and handling. Factor replacement into your budget; the tool's area figure lets you re-estimate the cost each time you re-cover.
What thickness of film should I use?+
Common greenhouse films are 150–200 micron (about 600–800 gauge) for the roof. Thicker film lasts longer and resists wind better but costs more. The tool sizes the area in m²; films are sold by area and thickness, so multiply by the price per m² for that thickness.
Can I use this for a low tunnel or net house?+
Yes — for a low tunnel set a small wall height and a modest rise; for a net house set the rise to zero for a flat top. The roof + sides geometry covers tunnels, net houses, polyhouses and shade structures alike. Just enter the real dimensions.
How do I cut wind damage to the cover?+
Use thicker, UV-stabilised film, fix it firmly with battens or trenched edges, keep it taut, and add the larger overlap allowance. Orient the structure to reduce wind load and repair tears promptly. A well-fixed cover lasts far longer than a loose one that flaps.