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Why Harnois?

Quality

Oval Tube

Structure

Design

Innovative plastic films

ROI

North-American greenhouse manufacturer since 1960

At Harnois, our oval tube greenhouse structure is engineered to deliver superior strength, light efficiency, and long-term performance in demanding commercial growing environments. Designed specifically for North American climate loads, this structural approach optimizes the strength-to-weight ratio of steel, reduces shading, and improves the durability of greenhouse coverings. The result is a high-performance oval tube greenhouse structure that supports stable climate control, higher yields, and a stronger return on investment throughout the greenhouse’s life.

Quality product

  • Structural Steel
    Elastic limit: Minimum of 50,000 psi vs 33,000 psi
    Predicts steel's response to wind and snow constraints
  • Galvanization Type
    Harnois Galvalume = 40+years
    Harnois Powercoat = 50+ years
    Standard G90 = 15 years
  • Hardware
    The hardware is provided with a zinc-nickel coating, of industrial quality, ensuring a durable assembly quality and good corrosion protection with a minimum resistance under 1200 hours salt spray test according to ASTM B117, which is normally 500 hours according to the market standards.
harnois_structural steel

Oval Tube

  • optimized structure resistance
    52% more resistant than other comparable profiles
  • No edges
    It increases the poly film durability because there is no sharp edges and therefore, less friction
  • Best ratio
    Our arches are made of oval tubing which offers the best ratio of strength to steel weight.
  • Load Capacity
    The oval tube has a superior load capacity for each arch, which allows greater arch spacing without compromising the oval tube greenhouse structure's integrity.

Structure

  • engineer stamp structure
    For the Ovaltech and Luminosa
  • harnois_neutral axis_drilling
    Drilling in the neutral axis
    Drilling performed on the neutral axis preserves structural strength while minimizing on-site drilling and self-drilling screws through the use of bolted, swedged-tube assemblies.
  • More Light Reaching the Crop
    Thanks to the superior strength of Harnois steel structures, fewer structural elements are required in the roof. This reduces shading and allows more natural light to reach the plants, directly contributing to improved photosynthesis and higher yields.
competition harnois_greenhouse_gable

Design

  • Optimal Roof Angle (45°)
    The 45-degree gothic roof angle, combined with high-quality plastic films, optimizes light quality by filtering specific light wavelengths beneficial to plant development. This design also improves internal climate stability, helping growers maintain more consistent growing conditions.
  • Higher Gable
    A higher gable increases the volume available for hot air accumulation, improving climate conditions at plant level.
  • Under-gutter (up to 20')
    A higher under-gutter height (up to 20 ft) provides greater internal volume, enabling better climate control and improved energy efficiency.
harnois_roof angle

Innovative greenhouse plastic films

  • 8-layers
    7 co-extruded layers + 8th layer on the surface of the film
  • Anti-Dripping
    Non-migratory anti-dripping system that lasts much longer, thus offering a decisive advantage in humidity management and making it possible to use the film for more years.
  • 7,2mil thickness
  • Light transmission (90-91%)
    Allow more light to enter the oval tube greenhouse structure. This becomes even more pronounced when ight incidence is low.
  • No mist
  • Low temperature
    It maintains its effectiveness at very low temperatures, even below −10 °C (14 °F), where traditional anti-drip films typically fail due to molecular crystallization.
  • Optimal Roof Angle (45°)
    The 45° roof slope creates optimal conditions for anti-drip performance, allowing our films to remain effective where traditional anti-dripping films require a minimum 30° inclination.
  • Double-inflated
    A crystal-clear outer film ensures maximum light transmission and mechanical resistance, while a thermic inner film minimizes heat loss.
oval tube greenhouse structure - why harnois

Better ROI

  • Fast and simple installation
    Reduced installation time and labor costs.
  • Lower operational costs
    Optimized ventilation and improved air volume reduce heating demand and energy expenses.
  • Longer replacement cycles
    High-strength plastic films and edge-free oval tubing reduce wear, extending covering lifespan.
  • Reduced disease pressure
    Improved climate control and condensation management protect crops.
  • Stable growing conditions
    More predictable production and planning.
  • Higher yields and crop quality
    Better light, climate, and structure performance drive results.
  • Long-term durability (40+ years)
    Extended lifespan reduces replacement and capital reinvestment.
  • Low maintenance design
    Fewer interventions, lower ongoing operating expenses.
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