The Octagonal is a garden showpiece: an eight-sided Western red cedar greenhouse with high eaves, a cupola and wide hinged double doors. Two automatic roof vents and two high-level louvre windows draw in cool air and let warm air out, so it stays comfortable on sunny days.
One size — 9'2" x 12'10" (101 sq. ft.) with a 9'8" peak. See the Dimensions tab for full specs.
Optional accessory kit with octagonal staging for two sides, an infill shelf for a third side and an upper shelf — select it above, or call or text us.
Where can I buy the Alton Octagonal?
From World of Greenhouses — an authorized Alton dealer with free shipping, financing and installer coordination. Call or text 732-806-7959 for current pricing and availability.
What upgrades are available?
Extra low- or high-level louvre side vents, aluminum bar capping, a high-level shelf, and staging on two sides and the rear — call or text us to put together your package.
Is it big enough to sit in?
Yes — at 101 sq. ft. with a 9'8" peak there's room for staging around the sides and a chair or small table in the middle.
Who makes Alton greenhouses?
Alton is a British cedar greenhouse maker that has built greenhouses in the UK since 1921. Exaco imports them to the US, and World of Greenhouses is an authorized Alton dealer.
How strong is it in wind and snow?
Alton greenhouses don't carry a US wind rating or code certification. In a sandbag load test, an Alton greenhouse roof held about 900 kg (roughly 2,000 lb) of sandbags. The steep 45° roof sheds snow well. Exaco recommends them for backyards with some shelter from nearby homes, fences or trees rather than wide-open, very windy sites — tell us about your site and we'll help you decide.
What foundation does it need?
A level, square concrete slab or concrete piers/footings. Exaco ships US Alton greenhouses with anchors to embed in concrete — pavers alone, as shown in Alton's UK manuals, aren't enough for US weather. We'll help you plan the base and anchoring for your site.
Is it a kit? Can you install it?
It ships as a kit with pre-assembled doors and windows and a metal base. Plan on roughly 2–3 days for 2–3 handy people, or use an installer — we coordinate one for you.
How is it delivered?
Free freight shipping to most of the contiguous US. It ships directly from the US distributor by truck, so the site needs truck access and someone there to receive and unload the crates. Call or text us for current lead time.
How much maintenance does cedar need?
Very little. The cedar is factory-treated and weathers naturally to a silvery gray (or you can apply a colored wood preservative before assembly to keep the warm tone). Clean the glass and frame once a year, ideally in late winter. The aluminum bar capping is virtually maintenance-free.
What warranty does it have?
A 10-year guarantee on the cedar framework against rot.
Do I need a permit?
Often, since this is a permanent structure — requirements vary by town, so check with your local building department before you order.
What if I have more questions?
Call or text us at 732-806-7959 — texting is the fastest way to reach us. We're happy to help.
