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Black Friday: 5% OFF on select brands with code BLACKFRIDAY5 + Free Shipping* on select items. Price Match Guarantee on all products. Some exclusions apply.

Grandio Summit 12x8 Greenhouse Kit 10mm Polycarbonate

by Grandio
SKU SUMMIT-128
Save 24% Save 24%
Original price $4,589.00
Original price $4,589.00 - Original price $4,789.00
Original price $4,589.00
Current price $3,499.00
$3,499.00 - $3,839.00
Current price $3,499.00
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  • Typical delivery 4 to 7 days*
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  • Manufacturer warranty included
  • No sales tax in most states*

Questions? Text or call +1 (307) 248-7227

*Exclusions apply. See Shipping and Returns.

Kit Options: Basic
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We're committed to your happiness with every purchase. Need assistance? Just reach out. You have 30 days from delivery to return items in their original condition. We process refunds promptly, usually within 3 business days of receiving your return.

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Why Choose the Summit 12x8 Greenhouse Kit for Year-Round Growing?

Actual size: 12' W × 8'1" L × 9.25' H Sizes: 12x8, 12x12, 12x16, 12x20, 12x24, 12x28, 12x32 Panels: 10mm twin-wall polycarbonate Frame: Heavy Duty Aluminum Ventilation: (4) roof vents + rain gutters Ratings: wind up to 76 mph; snow up to 25 lb/ft²*

The Grandio Summit 12x8 Greenhouse Kit is built for growers who want professional strength, long term durability and a controlled growing space that performs in every season. With its tall barn style roof, heavy duty aluminum frame and thick 10 mm twin wall polycarbonate panels, the Summit series provides commercial level stability and year round insulation. Whether you are starting seedlings, extending your growing season or managing delicate plants, the Summit 12x8 delivers a dependable, efficient environment.

Designed for both hobby growers and serious gardeners, this greenhouse blends premium materials with thoughtful engineering, ensuring excellent weather resistance, smooth daily usability and long lasting performance.

Why Choose the Summit 12x8 Greenhouse Kit?

Built for Harsh Weather

The Summit uses a 1.6 mm powder coated aluminum frame paired with UV protected 10 mm twin wall polycarbonate panels. This combination provides strong heat retention in the winter and effective solar diffusion in summer.
Its barn style shape also adds natural strength and stability, making the structure suitable for challenging climates when properly anchored.

Ventilation and Easy Access

With four roof vents positioned for consistent air circulation, the Summit 12x8 maintains optimal humidity and temperature even on warm days.
The sliding double doors hang from above for smooth operation and are supported by durable door wheels and lockable handles for added security.

Enhanced Features for Long Term Use

Included components such as rain gutters, a drain kit, an extreme snow load kit and a flat mount anchoring kit make the Summit 12x8 a reliable all season greenhouse right out of the box.
Cross roof trusses and cross corner bracing add structural reinforcement, improving durability and overall frame strength.

These details give you a greenhouse that is not only sturdy but also comfortable and easy to manage throughout the year.

BENEFITS

  • Strong Build for Tough Weather: Made with a solid 1.66m aluminum frame and thick, 10mm twin-wall polycarbonate panels, this greenhouse keeps your plants warm in cold weather and cool in the heat. Its design helps to keep temperatures stable, giving plants a safe, steady place to grow no matter the season.
  • Great Ventilation for Healthier Plants: With four roof windows and easy-glide double doors, this greenhouse allows plenty of fresh air inside, helping to keep the temperature and humidity just right for your plants. The doors are hung from above to move smoothly without sticking, making it easy to get in and out while keeping a tight seal.
  • Convenient and Long-Lasting Features: The Summit 12x8 comes with extra features like a rain gutter, drainage kit, snow load kit, and anchoring kit to keep it steady and secure. The doors have durable wheels and lockable handles, so you know your greenhouse is built to last. These thoughtful touches make it easier to keep your plants thriving for years.

The Summit 12x8 Greenhouse Kit offers the perfect setup for growing all year, giving you the strength, quality, and comfort you need to enjoy your gardening to the fullest.

SPECIFICATIONS

Frame Heavy Duty Aluminum
Color Powder-Coated Green
Panels 10mm Twin-wall UV-protected Polycarbonate
Doors Bind-resistant Sliding Double doors
Latch Magnetic latch doors with key lock
Reinforcement Cross-roof truss and cross-corner bracing
Hardware Stainless steel nuts and bolts
Rain Gutters Yes
Ventilation 4 Roof vents with adjustable manual openers/latches
Wind Rating Withstands winds up to 76 mph*
Snow Rating Maximum snow load of 25lbs./ft² of snow*

DIMENSIONS

Actual Size: 12' W x 8'1" L x 9.25' H

Door Size: 41.5" W x 85" H

grandio summit 12x8 greenhouse kit dimensions
GRANDIO GREENHOUSE MATERIALS VS OTHER BRANDS

WHAT'S INCLUDED IN THE PACKAGE?

Basic Kit Includes:

  • 10mm Twin-Wall Panels
  • (4) Roof Windows
  • Rain Gutters
  • Drain Kit
  • Extreme Snow Load Kit
  • Flat Mount Anchor Kit

Optional Premium Kit Includes:

  • 10mm Twin-Wall Panels
  • (4) Roof Windows
  • Rain Gutters
  • Base Kit
  • Drain Kit
  • Extreme Snow Load Kit
  • Flat Mount Anchor Kit
  • (4) Auto Roof Vent Openers
  • (1) Pack of 10 Plant Hangers
  • (1) Trellis Kit
  • (1) Drip Kit
  • (1) 8 oz. Brillianize Cleaner

ASSEMBLY VIDEO

Grandio Summit 12x16 Assembly Time-lapse - 1 minute video

Grandio Ascent 8x8 Assembly - 11 minute video

Grandio Summit Weather Stripping Installation

GRANDIO SUMMIT #1 BASE INSTALLATION

GRANDIO SUMMIT #2 ASSEMBLY INSTRUCTION

GRANDIO SUMMIT #3 PARTS LIST

Compare Grandio Greenhouse Models

Feature

Grandio Element 6x12 Greenhouse

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Grandio Ascent 8x12 Greenhouse

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Grandio Elite 8x12 Greenhouse

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Grandio Summit 12x8 Greenhouse

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Footprint (W x D) 6' x 12' 8' x 12' 8' x 12' 12' x 8'
Total Area 72 sq ft 96 sq ft 96 sq ft 96 sq ft
Peak Height 7'6" 7'9" 8" 9.25'
Sidewall Height 5'5" 5'5" 5'5" 5'5"
Frame Material Heavy-duty Aluminum Heavy-duty aluminum Heavy-duty aluminum Heavy-duty aluminum
Panel Material 10mm Twin-wall UV-protected Polycarbonate 6mm Twin-wall UV-protected Polycarbonate 10mm Twin-wall UV-protected Polycarbonate 10mm Twin-wall UV-protected Polycarbonate
Latch Easy-latch doors with double-ball catch Easy-latch doors with double-ball catch Easy-latch doors with double-ball catch Magnetic latch doors with key lock
Door Type Sliding Double Sliding Double Sliding Double Sliding Double
Ventilation (3) Roof vents (3) Roof vents (3) Roof vents (4) Roof vents
Warranty Lifetime frame / 10-year panels Lifetime frame / 10-year panels Lifetime frame / 10-year panels Lifetime frame / 10-year panels

Compare with Other Greenhouse Brands

Feature

Grandio Summit 12x8 Greenhouse

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Riverstone Monticello Black Premium Greenhouse

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EZ-Fit Greenhouse Kit

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Little Cottage Co. Colonial Gable Greenhouse

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Size 12x8, 12x12, 12x16, 12x20, 12x24, 12x28, 12x32 8x8, 8x12, 8x16, 8x20, 8x24 8x8, 8x10, 8x12, 10x12, 10x14, 10x16, 12x16, 12x20, 12x24 8x8, 8x12, 8x16, 10x12, 10x14, 10x16
Frame Material Powder-coated heavy-duty aluminum (1.6 mm thick) Commercial-grade extruded aluminum (black powder-coated) LP SmartSide® engineered wood siding with treated wood frame LP SmartSide® engineered wood siding with treated wood frame
Panel Material 10mm Twin-wall Polycarbonate 8mm Twin-wall Polycarbonate Corrugated polycarbonate roofing panels Corrugated polycarbonate roofing panels
Door Type Sliding double doors Hinged double doors Single door with 2 transom windows
(Optional Double Door Available)
Colonial Dutch door with 1 transom window
Ventilation 4 roof vents 1 Automatic roof vent(s) Operable windows (with screens) + 2 gable-end air vents Operable windows (with screens) + 2 gable-end air vents
Color Green powder-coat aluminum frame • clear polycarbonate panels Black powder-coat aluminum frame • clear polycarbonate panels Primed and ready to paint Primed and ready to paint
Included Accessories Rain gutters, snow load kit, anchoring kit Rain gutters, roof vent, base kit Shelves on 3 sides Shelves on 3 sides, hanging rods, 2 louvers
Optional Accessories

Drain Kit - Downspout for Grandio Greenhouse Gutter Systems, designed for installation at each of the four corners of the greenhouse. It’s made to be installed directly into the aluminum frame and gutter of the greenhouse. The easy-to-install downspout drain kit includes (4) 20mm black pipes, (4) gutter attachment gaskets, and (4) side wall brackets with screws. One kit has everything needed to add downspouts to a Grandio Greenhouse.

Automatic Roof Vent Opener - Automatically opens and closes the roof vent window based on temperature changes. The opener contains a metal cylinder with a mineral that expands when heated, pushing a piston to open the vent. When the temperature cools, the mineral contracts, and a spring closes the vent, resetting the piston. The vent opens and closes gradually, allowing the right amount of airflow for cooling.

Auto Louver Window Opener - Automatically opens and closes the louver window as the temperature changes. The opener has a metal cylinder with a mineral that expands when heated, pushing a piston to open the vent. As the temperature cools, the mineral contracts, and a spring closes the vent and resets the piston. The vent opens and closes gradually, providing just the right amount of airflow for cooling. This Auto Louver Opener attaches to the left side of your louver window.

Louver Window - add more ventilation to your greenhouse. Louver window frame comes powder coated in green, with 6mm twin wall polycarbonate panels.

The Drip Irrigation Watering Kit - is a water-efficient system designed for shrubs, trees, flowers, and bushes, covering up to 150 square feet with easy expandability. It's a DIY-friendly installation with no gluing required, using high-quality UV-resistant materials. The kit includes 24 pressure-compensating drippers (20 at 1 GPH, 2 at 2 GPH, and 2 at 4 GPH) for consistent water delivery to plant roots. A backflow preventer ensures water safety by preventing siphoning into the main supply.

Moisture Control Kit - featuring Anti Dust Tape and Waterproof All-Weather Silicone Caulk, protects your Grandio Greenhouse from insects, dirt, mold, and algae. The tape's 45-micron filters allow condensation to escape while preventing algae and mold growth with a fungicidal coating. Combined with the silicone caulk, this kit ensures long-lasting protection and maintains the greenhouse's pristine condition.

Shade Net - are essential for regulating greenhouse temperatures, especially during sunny spring, autumn, and summer days. Designed to reduce intense sunlight by 50%, they help keep your greenhouse cooler and prevent overheating.

Plant Hangers - These versatile plastic hangers are designed for greenhouse use, supporting shade cloths, hanging baskets with quarter-inch hooks, and stringing taller plants or vines. Easy to install, they simply twist into the roof rafter channels.

SHIPPING INFO

Lead Time is 1 to 2 days. Orders typically arrive within 1-7 business days, depending on your location:

  • West: 2-4 days
  • Northwest: 1-3 days
  • Southwest: 3-5 days
  • Midwest: 4-6 days
  • East: 5-7 days

Note: Delivery times are estimates and exclude order processing time. Delays may occur due to weather or carrier issues.

FAQ

Can one person assemble the Grandio Summit 12x8 Greenhouse Kit?
While the Grandio Summit 12x8 Greenhouse Kit is designed for DIY installation, it is recommended that at least two people work together for faster and safer assembly. The heavy-duty aluminum frame, tall barn-style roof, and large 10mm polycarbonate panels require alignment and lifting that may be difficult for one person to handle alone. Most customers complete the setup in 1–2 days with basic tools and two people.
Does the Grandio Summit 12x8 come with an anchoring or base kit?
Yes. The Grandio Summit 12x8 Greenhouse Kit includes a flat mount anchor kit and an extreme snow load reinforcement kit. These components provide a solid foundation for securing the greenhouse to wood, concrete, or compacted soil. A separate raised base frame is not required or included—anchoring is handled directly through the included hardware.
What are the benefits of 10mm twin-wall polycarbonate panels in this greenhouse?
The Grandio Summit 12x8 Greenhouse Kit uses 10mm twin-wall polycarbonate panels that offer excellent insulation, durability, and light diffusion. Compared to standard 6mm panels, these thicker walls help maintain stable temperatures inside the greenhouse, protect plants from direct UV exposure, and support heavier snow loads. The panels are also UV-treated to resist yellowing and cracking over time, making them ideal for year-round gardening in extreme climates.
Can I install automatic roof vent openers in the Grandio Summit 12x8?
Yes. The Grandio Summit 12x8 Greenhouse is compatible with Grandio's automatic roof vent openers, which are available as an optional accessory or included in the Premium Kit. These openers use a temperature-sensitive mechanism that automatically opens or closes the roof vents based on interior heat levels—no electricity required. This helps regulate airflow and reduces the need for manual venting.
What accessories are included with the Grandio Summit 12x8 Greenhouse Kit?
The standard Grandio Summit 12x8 Greenhouse Kit includes four roof vents, rain gutters, a drain kit, an extreme snow load kit, and a flat mount anchor kit. The optional Premium Kit adds auto vent openers, plant hangers, a trellis kit, a drip irrigation kit, and a Brillianize cleaner. Interior shelves and workbenches are not included but can be added separately.
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