160 sq ft of premium growing space under a nearly 8 ft peak. The Grandio Ascent 8x20 is built for growers who want the most a residential greenhouse can offer: heavy-duty powder-coated aluminum frame, 6mm twin-wall polycarbonate, 5 adjustable roof vents, and the steel base kit and snow load kit included as standard.
- 7 ft 9 in peak height and a 3 ft 6 in x 6 ft double sliding door fit people, wheelbarrows, and large containers
- 1.2 mm heavy-duty aluminum frame is rust proof and withstands winds up to 76 mph when properly anchored
- 6mm twin-wall polycarbonate panels insulate and diffuse UV for consistent growth in all seasons
- Snow load kit included, rated for a maximum snow load of 25 lbs per sq ft
- Steel base kit included for a rigid perimeter foundation on any surface
- 5 roof vents with multi-level handles plus built-in rain gutters
Best for: running multiple dedicated growing zones at once: seedlings, mature vegetables, overwintering tropicals, and cut flowers. A strong fit for small-scale market gardeners and homesteaders. It offers 25 percent more space than the 8x16, and an optional back door transformation kit creates a walkthrough layout.
What's included
- Powder-coated aluminum frame (green)
- 6mm twin-wall polycarbonate panels
- Bind-resistant double sliding doors with easy latch and double ball catch
- 5 roof vents, built-in rain gutters, and downspouts
- Heavy-duty steel base kit and snow load kit
- Stainless hardware, assembly tools, and anchoring components
Anchor options
Choose Wood for decks and timber platforms, Concrete for slabs and hard surfaces, or Dirt for direct soil installation with earth anchors. The included steel base kit is used with all three.
Premium upgrade
The optional premium upgrade adds 5 automatic roof vent openers, 20 plant hangers, a trellising kit, a drip irrigation kit, and Brillianize anti-static panel cleaner.
Specifications
| Height |
7 ft 9 in |
| Width |
8 ft |
| Length |
20 ft |
| Frame |
1.2 mm heavy-duty aluminum, powder coated green |
| Panels |
6mm twin-wall polycarbonate |
| Door |
Bind-resistant double sliding door, 3 ft 6 in x 6 ft |
| Roof vents |
5 |
| Rain gutters |
Built-in |
| Steel base kit |
Included |
| Snow load kit |
Included |
| Back door kit |
Optional |
| Snow rating |
25 lbs/sq ft maximum snow load |
| Wind rating |
Up to 76 mph when anchored properly |
| Extendable |
Yes, with Ascent extension kits |
Warranty
Lifetime warranty on the aluminum frame and a 15-year limited warranty on the polycarbonate panels.
Why buy from Renewable Outdoors
Shipping
Free ground shipping in the continental US.
Warranty support
We handle warranty claims with Grandio directly so you don't have to chase the manufacturer.
Returns
30-day returns on unopened items. See our return policy for details.
Frequently asked questions
How hard is assembly?
Plan a full weekend or two days with a helper for a greenhouse this size. The kit includes labeled parts, stainless hardware, required tools, and step-by-step instructions, and Grandio provides official assembly videos.
What foundation do I need?
The included steel base kit creates a rigid perimeter frame that works on concrete, wood decks, or bare ground. Just pick the matching anchor option so the hardware fits your surface. Earth installations use L-bolt anchors, often set in concrete for extra hold.
Can it be used year-round?
Yes. The twin-wall panels retain heat in cooler months and the 5 roof vents manage summer temps. Many owners add a small heater for frost protection and shade cloth in peak summer.
How does it handle wind and snow?
The Ascent is rated for 76 mph winds and 25 lbs per sq ft of snow when properly anchored, and the snow load kit comes standard rather than as an add-on.
