Janssens | Gigant Large Luxury Greenhouse with 4mm Tempered Glass Glazing

The Janssens Gigant Greenhouse is a showpiece of European design and engineering. With its impressive width, tall roofline, and customizable layout and height, this structure isn’t just a greenhouse—it’s an architectural centerpiece. Designed for professional growers, hospitality spaces, or homeowners who want a true luxury garden room, the Gigant offers unmatched strength, clarity, and style.

Key Features and Benefits

• Spacious and versatile design: Choose widths up to 20 ft, lengths up to 60 ft, and ridge heights up to nearly 14 ft, creating a true glasshouse environment for large-scale growing or entertainment.
• Premium materials: Built with a heavy-duty aluminum frame and 4 mm tempered safety glass for year-round durability and crystal-clear visibility.
• Custom options: Select your preferred RAL color, roof glazing type (4mm tempered glass or 10mm twin wall Heat Block polycarbonate), door and window layout and accessories to fit your unique space.
• Weather-resistant structure: Oversized aluminum profiles and stainless-steel fittings withstand strong winds, snow loads, and changing temperatures.
• Elegant, low-maintenance design: Powder-coated finish resists corrosion while providing a refined, architectural look that complements modern landscapes. Optional roof crests and finials for a more traditional look.

Perfect for Any Purpose

The Gigant Greenhouse is ideal for:

• Commercial growing or botanical display or retail spaces
• Luxury hospitality venues such as restaurants, hotels, or resorts
• Residential garden rooms and outdoor living lounges
• Pool enclosures or event spaces requiring abundant natural light

Take advantage of this beautiful greenhouse to create a unique area to enjoy. 

• House a Jacuzzi Tub and surround it with your favorite plants
• Create an Inspiring Art/Hobby Studio
• Set up a Cozy Tea House
• An Indoor / Outdoor Entertainment Room
• A Yoga/Exercise Room
• A Quiet Meditation/Relaxation/Reading Sanctuary
• House a swimming pool

Its expansive interior height accommodates tall crops, tropical plants, or stylish furniture, turning any outdoor area into a bright, climate-controlled oasis.

Optional Accessories

Customize your Gigant with:

• Integrated shelving and staging units
  
• Additional doors and windows
• Shade systems to manage light intensity
• Grow lights, heaters, seed trays, fly screens, decorative metal panels, and more
• Decorative cresting and finials for a refined finish

Frequently Asked Questions

Q: Can the Gigant Greenhouse be used year-round?
Yes. Its heavy-duty frame and high-quality glazing make it suitable for all-season use, even in cold or windy climates.

Q: Can I customize the size or color?
Absolutely. Choose from multiple widths, lengths, heights, and any classic RAL powder-coat color to match your property or branding.

Please call us at 888-648-5333 to schedule a free design session. You can customize the size and height, frame color, benches and shelves, extra doors, windows, and roof vents, shelving, and many other functional and decorative aspects of your greenhouse.

Q: What’s included in the kit?
Each Gigant Greenhouse includes the complete aluminum frame, glazing panels, doors, roof vents, hardware, and assembly instructions.

Q: Is professional installation required?
Due to its scale and weight, professional assembly is strongly recommended for safety and performance.

This greenhouse is not designed to be a build-it-yourself kit. It should be assembled by experienced builders who are familiar with these products and their assembly. Due to the size of this greenhouse we recommend that you check your local building code for any required permits and view the foundation construction guide prior to ordering.

NOTE: Please call (888) 648-5333 for ordering information, including custom orders, and a cash payment discount when paying with a bank wire transfer.  Standard delivery service is curbside with lift gate.  We have an added-cost flatbed plus forklift delivery option available if needed.  Shipping turnaround on stocked sizes is less than a week, 14-16 weeks for non-stocked sizes and custom orders.

Specifications

Wall Glazing:

• 4mm tempered glass panes

Roof Glazing: 

• 4mm tempered glass panes OR
• 10mm twin wall polycarbonate

Frame:

• 17 gauge tubular aluminum extrusions
• Heavy duty portal frame supports
• Heavy duty gable end supports

Colors:

• Black (RAL 9005m)
• Fir Green (RAL 6009m)
• White (RAL 9010m)
• Custom Colors: choose a color from the RAL Color System (at additional cost)

Dimensions

Most Gigant greenhouse sizes are offered only as a special order of custom order. When custom ordering, the length, width, and wall height may be chosen within certain parameters. Note that the width and wall height of the greenhouse will determine both the peak ridge height and the roof pitch.

There are 4 widths, 4 wall heights, and 20 lengths.  That plus 3 standard colors makes over 900 models. With a custom color, there are many thousands of combinations.

The charts below show possible dimensions (*) for the Gigant greenhouse. Note that the width and wall height of the greenhouse will determine both peak height and roof pitch.

* Dimensions are approximate conversions from metric measurements and should not be relied on for assembly purposes.

Extra Height

One major advantage of the Gigant greenhouse is the option to extend its wall and peak height by adding a second level of glazing panels to the side walls. The standard wall height is 6'8", the options for extension are:

• 1'0" - wall height becomes 7'8"
• 1'8" - wall height becomes 8'4"
• 2'11 - wall height becomes 9'7"

Additional Options

Doors & Windows: There is no standard configuration of doors and windows for custom units. You may select your desired options. Please note that double doors can only be installed in walls that contain at least 4 panels.

Glazing: You may substitute narrow panels (~1'2" width) for the standard glazing panels (~2'4" width) at a ration of 2:1. This will not affect the overall dimensions of the greenhouse.

For the roof, you may substitute 10mm twin wall Heat Block polycarbonate panels instead of the glass panels.  This glazing combination is referred to as Hybrid glazing.

Decorative Panels: You may choose to add decorative metal panels along the bottom of the side walls, identical to those found on the Retro Victorian greenhouse.

INSTALLATION MANUAL