Larger Growing Footprint
Available in 17 x 10 ft or 21 x 10 ft to give you room for plants, benches, pathways, and storage.
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$19,250
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Product Details
The Alton Wooden Octagonal Greenhouse combines distinctive architecture with practical growing space, creating a striking focal point for any garden. Its tall octagonal design provides generous interior space while making efficient use of the footprint, giving gardeners room for plants, shelving, storage, and relaxation. The structure brings together classic greenhouse styling and the character of a garden retreat, making it suitable for both serious growing and everyday enjoyment.
Built by Alton Cedar Greenhouses, the Octagonal is crafted from premium Grade 1 knot-free Western Red Cedar, selected for its natural beauty, strength, and insulating properties. The cedar frame is paired with durable aluminum capping and clear 3mm toughened glass to provide a strong, light-filled growing environment. Thick timber glazing bars, measuring 1.73" × 1.73" and 1.73" × 2.71", add structural strength and stability, while the superior jointing system helps simplify assembly and reinforces the overall frame.
Designed for year-round usability, the greenhouse offers natural insulation through its cedar construction, helping reduce temperature fluctuations inside the structure. The spacious interior includes full wraparound shelving, a lockable hinged door, two automatic roof windows measuring 24" × 19", and two automatic louvre windows measuring 31" × 41" for improved ventilation. It also includes a base frame with aluminum capping, guttering and downpipes, and a shed floor, providing a comprehensive setup for growing, organizing, and enjoying the space.
With over 100 years of greenhouse craftsmanship in the UK, Alton combines traditional woodworking expertise with high-quality materials and practical greenhouse engineering. The Octagonal measures 9'8" long × 9'2" wide, with a 9'8" peak height and 6'2" sidewall height, providing approximately 101.4 sq. ft. of floor area. The 2'5" × 6'7" lockable door provides convenient access, while the combination of cedar framing, toughened glass, aluminum components, and included ventilation and drainage features makes this a substantial long-term garden structure, backed by a 10-year frame warranty.
What’s Included
- Cedar framing, glazing, and hardware
- Base frame with aluminum capping
- Guttering and downpipes
- Shed floor
- 1 lockable hinged door — 2'5" × 6'7"
- 2 automatic roof windows — 24" × 19"
- 2 automatic louvre windows — 31" × 41"
- Full wraparound shelving
Technical Specifications
Build & Materials
Brand: Alton, distributed by Exaco, manufactured in the UK
Frame: Grade 1 knot-free Western Red Cedar with thick timber glazing bars
Glazing: 3mm clear toughened glass throughout
Aluminum: Aluminum foundation frame and capping
Foundation: Integrated aluminum base frame that raises the cedar structure off the ground
Design: Tall octagonal structure designed for spacious growing and relaxation
Ventilation
Roof Windows: 2 automatic roof windows, 24" × 19"
Louvre Windows: 2 automatic louvre windows, 31" × 41"
Ventilation System: Automatic roof windows provide hands-free ventilation as temperatures rise
Louvre Ventilation: Lower-level louvre windows support continuous airflow and circulation
Performance & Construction
R-Value: Glass 0.95; Western Red Cedar 1.35
Roof: Octagonal design with tall, spacious interior
Rainwater Collection: Integrated guttering and downpipes
Glazing Bars: Thick timber glazing bars measuring 1.73" × 1.73" and 1.73" × 2.71"
Foundation: Aluminum base frame included
Dimensions
Floor Area: 101.4 sq. ft.
Length: 9'8"
Width: 9'2"
Peak Height: 9'8"
Sidewall Height: 6'2"
Door Size: 2'5" × 6'7"
Other
Door: 1 lockable hinged door
Shelving: Full wraparound shelving included
Floor: Shed floor included
Warranty: 10 years on frame
Manufacturing: Made in the UK
Installation & Manuals
Assembly typically takes 2–3 days with a crew of 2–3 people — this isn't a same-afternoon build, largely due to the glass glazing work and the size of the larger models. Buyers should plan the timeline and labor accordingly, especially if they're coordinating with a foundation contractor beforehand.
Manual
Delivery & Prep
Free shipping to all 48 contiguous states
Delivery time: 8–13 business days
Ships via LTL freight (curbside): liftgate drops the pallet at ground level; plan on 2–3 people to move it from the curb to your install site
Outside the mainland US (Alaska, Hawaii, international)? Shipping terms need to be confirmed separately
Warranty & Returns
Warranty
Damages
Please inspect the packaging of your item(s) upon arrival. If you notice any damage, make note of it when signing for delivery. If your item(s) arrive damaged, please contact us with photos and we will process an insurance claim on your behalf.
Cancellations & Refunds
Orders cancelled after 48 hours are subject to a $20 administration fee, whether or not the order has shipped. If the order has already shipped, the buyer is also responsible for actual return shipping charges. Refunds are issued only to the original credit card used at the time of purchase.
Many of our items are large and heavy, and cannot be returned for buyer's remorse. In these cases, all sales are final.
Returns (RMA)
In certain situations, we will accept a return through our RMA department. The buyer is responsible for full return shipping costs. All returns must be pre-approved by our RMA department before being shipped back.
Cambridge Features
Classic Cedar Style With A Stately T-Shaped Design
The Cambridge T-Shaped Cedar Half-Boarded Greenhouse brings warm Western Red Cedar, toughened glass, and a tall orangery-style layout together for a beautiful, practical backyard growing space.
Spacious Grow Area
Choose from 154 sq. ft. or 194 sq. ft. of floor space for larger plant collections and flexible growing plans.
Tall usable space
The taller design gives you better headroom, more comfortable movement, and extra room for growing.
T-shaped orangery design
The stately T-shaped layout adds a strong focal point to your backyard and creates a more elevated garden feature.
Western Red Cedar frame
Natural cedar helps insulate the greenhouse, reduce temperature swings, and create a more stable growing environment.
Rot-resistant construction
Western Red Cedar naturally resists rot, handles moisture well, and offers long life with minimal maintenance.
Built-in Details
Designed for airflow, drainage and everyday use
Features for ventilation, durability, insulation, and a better greenhouse experience.
Automatic roof vents
24" x 24" roof vents open and close without electricity to help control airflow and temperature.
Manual louver windows
31" x 41" louver windows add side airflow when plants need extra ventilation.
Sealed roof glass
Aluminum roof caps create a tighter seal for better insulation and added weather protection.
Lockable hinged door
A single lockable hinged door with a low threshold makes entry secure, simple, and easy to use.
Toughened glass panels
3mm toughened glass sits tightly in the cedar frame for a clearer, stronger build with less rattling.
Protected aluminum base
The aluminum base keeps the wood off the ground to help reduce early rot and long-term wear.
Compare models
Compare Cambridge T-Shaped Sizes
Find the Cambridge size that fits your space, growing goals, and garden layout.
Alton Octangle 10 x 10
From $19,250
- Dimensions 10’9″ W × 16’8″ L
- Grow Space 179 sq. ft.
- Doors 1 lockable hinged door
- Roof vents 2 automatic roof vents
- Louvered window 2 manual included
- Misting system Not Included
- Best for Balanced growing space
Cedar Westminster 11 x 19
From $34,650
- Dimensions 10’9″ W × 18’9″ L
- Grow Space 202 sq. ft.
- Doors 1 lockable hinged door
- Roof vents 5 automatic roof vents
- Louvered window 4 manual included
- Misting system Not Included
- Best for Smaller garden layouts
Cedar Cambridge Tshaped 10 x 17
From $30,250
- Dimensions 16'8" L 9'11" W
- Grow Space 154 sq. ft.
- Doors 1 lockable hinged door
- Roof vents 4 automatic roof vents
- Louvered window 4 manual included
- Misting system Not Included
- Best for Largest plant collections
15-year Janssens frame warranty
Every Royal Victorian greenhouse is backed by Janssens' 15-year frame warranty, with durable powder-coated aluminum construction made for long-term outdoor use.
Optional Additions
Build out your Greenhouse for the way you grow
Additions can help tailor your greenhouse to your needs.
Our team can help you choose what makes sense for your setup.
Cooling and airflow
Shadecloth, exhaust fans, and fly screens can help manage heat, airflow, and pests.
Growing and storage
Seed trays, shelves, and work surfaces help organize plants, tools, and supplies.
Entry and access
Threshold, door, ramp, and stem wall options can make entry easier based on your site.
Seasonal growing
Heaters, thermostats, and winter covers can help support colder-weather growing.
Planning Ahead
Prepare Your Site Before Your Cambridge Greenhouse Arrives
The Cambridge T-Shaped Cedar Greenhouse features cedar, glass panels, and a porch entry. Prepare the site, foundation, and water access for installation.
Foundation prep
The Alton Wooden Octagonal Greenhouse should be installed on a flat, level, and stable foundation. A properly prepared base provides consistent support for the cedar frame, toughened glass, and integrated aluminum base frame, while keeping the structure level as the ground settles or changes with the seasons. The aluminum base frame is designed to raise the cedar structure off the ground, helping reduce the risk of early rot, but it still needs to sit on a solid, stable surface. Taking the time to prepare and level the foundation before assembly helps maintain proper alignment of the door, roof windows, louvre windows, and glazing, and gives the greenhouse a stable starting point for long-term use.
Anchoring
Once the foundation is ready, the greenhouse needs to be anchored securely to it. Use the manufacturer-recommended hardware for your region's wind and snow load — anchoring requirements aren't one-size-fits-all, and what holds a structure firmly in a low-wind, low-snow region may not be adequate somewhere with heavier seasonal loads. Matching your anchoring hardware to local conditions is part of making sure the greenhouse stays put and performs as expected through the seasons it's actually going to face.
Water and power
If you're planning to run water or electricity to the greenhouse — for irrigation, misting, heating, lighting, or anything else — those utility runs need to be planned before your site work is finished, not after. Coordinate with your electrician and plumber early so water and power lines can be brought to the greenhouse footprint as part of the same site preparation, rather than trenching or rerouting once the structure is already in place.
DIY & Installer support
Whether you're a confident DIYer or you'd rather bring in a professional, there's a path for either approach. For those installing it themselves, the groundwork above (foundation, anchoring, utilities) is the core of what to plan for. For those who'd prefer help, support is available to connect you with vetted installers so the greenhouse goes up correctly the first time.
Need help planning ahead?
We can help you think through foundation, utilities, delivery access, and installer support before your greenhouse ships.
Delivery
What to expect when your greenhouse ships
Before delivery, you'll receive tracking details and guidance so you know what's coming, where to place it, and how to store the parts before assembly.
Freight delivery
Your greenhouse ships by LTL freight and is delivered curbside. Greenhouses typically arrive in about 8 to 13 business days, including packing and transit time.
Plan for large crates
The Cambridge includes cedar frame sections, toughened glass panels, aluminum capping, and long components, so plan enough space for drop-off and temporary storage.
Unload safely
The driver will unload the freight shipment curbside. Have help available to move long cartons, glass panels, frame sections, and cupola components after delivery.
Store parts dry
Store all greenhouse components in a garage or covered dry area until assembly. Keeping everything protected helps prevent packaging, frame, and glass issues before install.
Frequently Asked
Quick answers around choosing, ordering, delivery, and setup.
The Cambridge works well for year-round growing, plant collections, seed starting, garden-room use, and relaxed outdoor living.
Your VI46 ships with the greenhouse frame, glazing, and the hardware needed for assembly, along with setup guides. See the specifications above for a full parts breakdown, or reach out to our team with any questions.
Yes. The VI46 supports a range of optional additions—including shelves, shade cloth, and fans—so you can tailor it to your setup at any time. Explore the add-ons above to build out your greenhouse.
Permit requirements vary by location. Some areas require a permit for a structure of this size, so we recommend checking with your local building department before installation.
Yes. Built with durable powder-coated aluminum and backed by a 15-year frame warranty, the VI46 is made for long-term outdoor use. With added insulation and optional heating, it supports growing through cold-weather months.
Our greenhouses use rust-resistant aluminum frames paired with tempered safety glass or twin-wall polycarbonate, so they stay durable and beautiful through every season.
Absolutely. With proper insulation, ventilation, and optional heating, our greenhouses support growing through every season.
Most greenhouses can be assembled over a weekend with two people. Larger models may take a little longer, and clear step-by-step guides are included with every kit.
Yes. A level base such as a concrete slab, paving, or a purpose-built base kit keeps the structure stable and square over its lifetime.
We offer free curbside freight delivery on greenhouse orders within the contiguous US. Any surcharges for remote areas are shown clearly at checkout.
In-stock greenhouses typically ship within 3–5 business days, with freight delivery arriving 1–2 weeks later depending on your location.
Our greenhouses are backed by manufacturer warranties, including up to a 15-year warranty on Janssens frames. Full coverage details are listed on each product page.
Reach out with your order number and a quick photo, and we'll arrange a replacement part right away at no cost for qualifying issues.
Financing Now Available!
Explore low-rate financing options for qualified customers, including greenhouse structures, accessories, and foundation costs.
Need help planning?
Not sure which model, size, glazing, or setup makes sense for you? Our team can help you compare options, plan your site, and understand the steps before you order.
