Expert Greenhouse Construction Services
Greenhouse construction is a long-term investment, and getting it right from day one determines your profitability for decades. Since 1965, Harnois has delivered expert greenhouse construction across North America, completing more than 20,000 projects for commercial growers, institutions, and research facilities. We design, engineer, and manufacture every structure at our Quebec facility, giving you a single accountable partner from blueprint to first harvest.
What Makes Greenhouse Construction Complex
Not every greenhouse construction project is the same. The right structure depends on your climate, your crops, your site conditions, your local building codes, and your long-term production goals. A structure built for a tomato producer in Ontario faces completely different engineering requirements than one built for a nursery in the Carolinas.
At Harnois, our in-house team of engineers, agronomists, and project managers evaluates every variable before a single bolt is ordered. We provide stamped engineering plans to support your local building permit application, a step many contractors skip, leaving growers exposed to compliance issues mid-build.
Our structures are engineered to withstand snow loads up to 622 kg/m² (127 psf) and wind speeds up to 250 km/h (155 mph). For growers operating in northern climates, structural certainty is not a bonus, it is a baseline requirement.
“We got specs on the weight rating, snow load, what the structures could handle. Other companies hadn’t done the math. With Harnois, the certainty was there.” — Andrew Plantinga, Facility Manager, Van Belle Finished Plants
Our Greenhouse Construction Process: 5 Steps, 8 to 15 Weeks
Every Harnois greenhouse construction project follows a proven, transparent process:
Step 1 — Discovery & Evaluation (Day 1 to 2 weeks) We assess your objectives, crops, site, and budget. A site visit or remote analysis confirms structural compatibility and ensures the proposed solution fits your exact situation.
Step 2 — Engineering & Design (1 to 2 weeks) Our engineering team designs your structure in full compliance with local codes and your crop-specific requirements. This is where your greenhouse is built — on paper first, precisely.
Step 3 — Approval & Planning (2 to 4 weeks) After you approve the final design and quotation, manufacturing and delivery are scheduled to your timeline. No surprises, no scope creep.
Step 4 — Manufacturing (5 to 8 weeks) Your structure is built at our Quebec facility using high-grade steel and the covering system best suited to your production goals — polyethylene film, polycarbonate, or glass. We control quality at every stage because we manufacture everything in-house.
Step 5 — Delivery & Installation (1 to 2 weeks) Shipping is coordinated and greenhouse construction installation is prepared for efficient, professional setup on your site. You receive a complete, operational growing environment ready to produce.
Explore our full range of commercial greenhouse structures to identify which structural system fits your project best.
Advanced Technologies Integrated Into Every Build
Modern commercial greenhouse engineering goes far beyond steel and plastic film. At Harnois, we integrate advanced growing technologies directly into our engineering process:
Climate Control & Energy Efficiency: Our structures support high-efficiency heating systems, automated ventilation, and AI-driven micro-climate management for maximum predictability in your growing environment. Our Vermax glass greenhouse platform achieves a peak coefficient of performance (COP) of up to 7.5, making it one of the most energy-efficient controlled environment agriculture (CEA) solutions available in North America.
Water Management: We engineer closed-loop irrigation systems that optimize water use and minimize waste. Our most advanced platform, the Vermax, incorporates a revolutionary circular water treatment system that achieves zero wastewater after startup, a critical advantage as water regulations tighten across agricultural regions. According to the Food and Agriculture Organization of the United Nations, irrigated agriculture accounts for 70% of freshwater withdrawals globally, making precision water management in greenhouses a measurable competitive advantage.
Integrated Pest Management (IPM): Rather than relying on synthetic pesticides, Harnois-engineered greenhouse environments support the deployment of biological control methods, beneficial insects, controlled airflow, and sealed growing environments, reducing chemical inputs and producing healthier crops.
Why Growers Choose Harnois for Greenhouse Engineering
“We got specs on the weight rating, snow load, what the structures could handle, we needed greenhouses that could host a wide variety of crops. Other companies hadn’t done the math. With Harnois, the certainty was there.” — Andrew Plantinga, Facility Manager, Van Belle Finished Plants
That certainty comes from more than 60 years of engineering experience and a vertically integrated approach that no reseller can match. As a family-owned company manufacturing entirely in Canada, we maintain direct control over material quality, structural standards, and lead times.
Our commercial greenhouse capabilities cover the full project lifecycle, and our completed greenhouse projects demonstrate the range of structures we have engineered across produce, floriculture, research, and institutional markets.
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