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Overview

The Alton Westminster cedar greenhouse from Britain combines natural beauty with expert craftsmanship. Drawing on over a century of greenhouse expertise, Alton designed the Westminster to combine elegance with long-lasting performance. Built from Grade A knot-free Western Red Cedar, each piece is treated to resist aging, moisture, and rotting. Strong mortise-and-tenon joints and a raised aluminum frame protect it from ground moisture and ensure exceptional stability. Aluminum bar capping secures each glass pane, extending the structure’s life even in harsh conditions.

The Westminster is engineered for ease and reliability. Its steep 45° roof pitch helps to prevent snow buildup, while pre-assembled doors and windows save time during installation. The inward-swinging single door locks securely, and the built-in louvred side vents, combined with automatic roof vents, create consistent airflow and ideal growing conditions. Every detail is carefully crafted in the United Kingdom, combining practicality with timeless style. Decorative Victorian finials are an optional add-on for all sizes.

 

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Key Features

Mortice-Tenon and Tongue-Groove Framing Joints

Mortice-Tenon and Tongue-Groove Framing Joints

Easy to assemble and adds strength
Aluminum Base

Aluminum Base

Wood never touches base to protect from water damage
Gutter and Downspout

Gutter and Downspout

For water collection or drainage
Roof Vents

Roof Vents

Featuring automatic opener system
Louvre Window

Louvre Window

Manual opening for airflow (automatic openers available)
Hinged Door

Hinged Door

Pre assembled Low threshhold single with locking handle and key
Aluminum Capping

Aluminum Capping

Seats the glass panels securely, low maintenance, high durability
Steep Roof Pitch

Steep Roof Pitch

More space equals more air and headroom and allows for snow to slide off easily
Guarantee

Guarantee

Free 10 year framework guarantee on all models we carry
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Specifications

Glazing: Toughened safety glass with screw-in bar clamping (capping)
Frame: Extra strong cedar

10x16

Suggested Retail: $34,650
Length: 16'8"
Width: 10'9"
Peak Height: 11'1"
Sidewall Height: 5'7"
Area: 179 sq. ft.
Roof Pitch: 45 degrees
Doors: 1 Lockable Door with Keys
Windows: 4 Roof Vents w, 3 Louvre Window
Window Openers: 4 Automatic (Roof), 3 Manual (Louvre)

10x18

Suggested Retail: $36,850
Length: 18’
Width: 10'9"
Peak Height: 11'1"
Sidewall Height: 5'7"
Area: 202 sq. ft.
Roof Pitch: 45 degrees
Doors: 1 Lockable Door with Keys
Windows: 5 Roof Vents w, 4 Louvre Window
Window Openers: 5 Automatic (Roof), 4 Manual (Louvre)

10x20

Suggested Retail: $38,500
Length: 20'10"
Width: 10'9"
Peak Height: 11'1"
Sidewall Height: 5'7"
Area: 224 sq. ft.
Roof Pitch: 45 degrees
Doors: 1 Lockable Door with Keys
Windows: 6 Roof Vents w, 4 Louvre Window
Window Openers: 6 Automatic (Roof), 4 Manual (Louvre)

Accessories

Comes Standard With

  • 3mm safety glass with screw-in aluminum capping
  • Wide single door with lock and low threshhold
  • Victorian style aluminum guttering with downspout
  • Automatic opening roof vents
    • 10x16(4)
    • 10x18(5)
    • 19x20(6)
  • Louvre windows
    • 10x16(3)
    • 10x18(4)
    • 19x20(4)

Can Also Add

  • 2 slat shelf staging
  • 4 slat shelf staging
  • Victorian cresting

Frequently Asked Questions

How do cedar greenhouses compare to other materials?

Cedar is a premium greenhouse frame material because it is naturally resistant to rot, decay, and insects. It is structurally strong and stable, yet lighter than many hardwoods. Unlike aluminum, cedar does not conduct heat or cold as quickly, which can slightly reduce temperature transfer through the frame. Over time, it weathers gracefully and maintains its structural integrity for decades when properly maintained. For buyers who want a durable, natural, and architecturally warm frame material, cedar is a premium choice.

Do I need a professional assembler for my Alton Cedar greenhouse? If so, how do I find one?

The Alton Cedar greenhouses do have more pieces and steps to the assembly than our other greenhouses. We have found that if you are intending to have a DIY assembly, it is very helpful to have a good knowledge of working with wood and have tools on hand. Taking your time during assembly and reading through the manual ahead of time helps immensely. Many people who have purchased the Alton cedar greenhouses do end up hiring an assembler. We do maintain a referral list of independent assemblers, please give us a call or email us and let us know where you are located and your greenhouse and we put you in touch with a couple assemblers in your area. If you prefer to work with someone local -handyman businesses and landscapers are great assemblers too! Exaco does provide all US customer support and we are here to help with any assembly questions that you or your assembler may have. Just give us a call!

What if I need assembly help?

Exaco is here to help! Our friendly customer support staff is REAL PEOPLE who have assembled these greenhouses and are very familiar with the parts and pieces. Please give us a call or email us. We are also able to video calls via Facetime or Google Meet as needed. We want to help you to get through any assembly questions so you can get to the fun part – enjoying your new greenhouse!

Where are Alton Cedar greenhouses made?

Alton’s parent company is The Greenhouse People located in the UK. The Alton greenhouses are manufactured in Stoke-on-Trent in England.

Can someone help me decide which greenhouse is best for me?

Our retailers are great resources to reach out to discuss greenhouses – and our Exaco customer service team is always ready to help your dream greenhouse come to life – we are just a call away. Over the years we have personally supported many customers choose their greenhouse and options – and that expericence goes a long way. You can also find additional resources and inspiration on our blog too.

Do I need a permit?

You might need a permit. Not everyone does and even sometimes those who do need a permit do not apply for one. Each municipality sets their guidelines for what types/size of buildings need a permit in their area – sometimes this is based on square footage or whether they consider it a “permanant structure” – but this is all decided by your local permit office. If you are applying for a permit, you should always go through this process BEFORE you order your greenhouse – depending on local wind/snow load requirements you may need additional reinforcements or supports to reach your local requirements. You may also find other restrictions for placement that may mean you have to limit the size or location. If you are going to get a permit, it is always best to know the restrictions ahead of time.

Resources & Documentation

Testimonials

  • “Greetings from Humboldt County, California. Loving our new greenhouse! It is holding up to the storms well. 40 knot winds last night”

    - Claudia

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