Alton Westminster Cedar Greenhouse

Alton Westminster Wooden Greenhouse

Crafted by Alton. Offered by South Table Sheds. Inspired by Nature. Built for Life.

Timeless Craftsmanship Rooted in Heritage

With over a century of experience, Alton has perfected the art of greenhouse design. The Alton Westminster Wooden Greenhouse, available through South Table Sheds, showcases this legacy by blending traditional woodworking with modern performance. Whether you’re nurturing heirloom tomatoes or creating a peaceful garden sanctuary, this structure is designed to grow with you—season after season.

Available in three sizes:

• Westminster 16'8''  - 179 sq. ft. (16'8" L x 10'9" W x 11'1''Peak Height)
• Westminster 18'      - 202 sq. ft. (18' L x 10'9" W x 11'1'' Peak Height) 
• Westminster 20'      - 224 sq. ft. (20'10" L x 10'9'' W x 11'1'' Peak Height)

Includes:  Ridge Cresting, Capping and slat shelves along one long side

Free Shipping (Continental US)

Why Gardeners Choose the Westminster

•  Superior-grade cedar for strength and natural beauty
•  Weather-protected foundation and hardware
•  Expertly engineered for all-season growing
•  Made in the UK by Alton, a leader in greenhouse design
•  Sold by South Table Sheds—trusted for quality and service

Built to Last

At the heart of the Westminster’s enduring quality is:

•  Grade 1 Western Red Cedar—a premium, knot-free timber known for its longevity and natural resilience. Each cedar panel is precision-milled and treated to maintain its warm color and resist the damaging effects of water, insects, and decay.
• Mortise-and-tenon joinery, combined with tongue-and-groove assembly and cast aluminum gussets, provides strength you can rely on.
• An elevated aluminum base frame keeps the wooden structure clear of ground moisture, extending its life and minimizing maintenance.

Crystal-Clear Panels

Outfitted with 3mm tempered safety glass, the Westminster offers clear views and reliable insulation. The steep 45-degree roof angle helps snow slide off effortlessly, making it well-suited for challenging weather conditions.

Doors and windows arrive pre-assembled for ease of installation. A low-threshold entrance with a keyed lock and durable handle combines accessibility with peace of mind.

Thoughtful Ventilation for Healthy Plants

To keep temperatures steady and airflow optimal, the Westminster features:

• Roof vents with automatic openers that react to internal temperature

• Louvre side windows with manual openers for additional cross-breeze

These elements work together to provide a self-regulating environment—ideal for maintaining a thriving garden throughout the year.

 

Lasting Rewards

Whether you're cultivating produce, flowers, or a peaceful escape, the Alton Westminster Wooden Greenhouse delivers exceptional performance in a design that will enrich your outdoor space for decades.

Assembly required. Beauty guaranteed.
Order now — limited quantities available.

Features

Aluminum Base Wood does not touch base, protects from water
Mortice-Tenon and Tongue-groove Framing Joints Easy assembly and add strengths
Gutter and Downspout  Water collection or drainage
Roof Vents Automatic Opener
Louver Window Manual opening for airflow
Hinged Door Pre-assembled  with locking handle and key
Aluminum Capping Seats the glass panels securely, high durability
High Eaves Overlapping roof glass prevents leakage

Specifications

	Small (16'8'' L)	Medium (18'L)	Large (20'L)
Area	179 sq. ft.	202 sq. ft.	224 sq. ft.
Length	16'8''	18'	20'
Width	10'9''	10'9''	10'9''
Peak Height	11'1''	11'1''	11'1''
Sidewall Height	5'7''	5'7''	5'7''
Roof Pitch	45 degrees	45 degrees	45 degrees
Doors	1 Lockable Door with Keys	1 Lockable Door with Keys	1 Lockable Door with Keys
Windows	4 Roof Vents, 3 Louvre Window	5 Roof Vents, 4 Louvre Window	6 Roof Vents, 4 Louvre Window
Window Openers	4 Automatic (Roof), 3 Manual (Louvre)	5 Automatic (Roof), 4 Manual (Louvre)	6 Automatic (Roof), 4 Manual (Louvre)
Materials	Grade 1 Western Cedar & 3mm tempered safety glass	Grade 1 Western Cedar & 3mm tempered safety glass	Grade 1 Western Cedar & 3mm tempered safety glass

 

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

Shipping and Delivery

Shipping

• Free Shipping in Continental US. 
• Additional shipping fees may apply for custom-quoted products, rural locations, or areas with limited access. Costs are determined based on freight carrier quotes and any necessary service upgrades.

Delivery

• CURBSIDE DELIVERY.  Anything more than that – i.e. flatbed/forklift or up the driveway may incur additional charges.
• All our deliveries are trucks with a liftgate.  When needed we can request a flatbed/forklift but often not necessary.  
• The carrier will call the customer for a delivery appointment when it reaches the destination terminal.
• The customer should be there to receive the delivery and notify us if there is any damage. 
• Do not refuse deliveries – we will send replacement parts. 
• Let us know asap if you do see damage. It will be quicker for us to send replacement parts.

Assembly

• The greenhouse kit comes with an assembly guide.
• South Table Sheds can recommend name/phone numbers of assembly technicians.
• South Table Sheds can be hired for assembly in the Denver, CO area. Please contact us for more information.
• Level of Effort
  • Installation requires two people minimum.
  • Not considering site preparation – the assembly should take between 6-10 hours, depending on how many shelves are bought and/or the foundation frame is added.

 

Assembly Instructions

Assembly Extension Instructions

Warranty

This product carries a limited warranty, which covers the following:

 

·        Aluminum frame and stainless steel hardware (up to 15 years from date of purchase)

·        Defects in material and workmanship when properly assembled using only manufacturer’s original equipment parts in accordance with manufacturer’s assembly instructions (up to 10 years from date of purchase)

 

Exclusions:

 

The warranty does NOT cover the following components, for which replacement parts may be provided at a reasonable cost:

 

• Tempered glass glazing
• Operating parts (such as pistons in automatic window openers)
• Other accessories provided with the greenhouse which are breakable in ordinary use.

 

The warranty does NOT cover damage resulting from any of the following:

 

• Excessive loads placed on the packed product and/or parts
• Glazing breakage caused by large hail, rocks or other projectiles (including rocks thrown by a lawnmower)
• Use of force, incorrect handling, or inappropriate use, neglectful use or assembly or maintenance, commercial use or use other than for personal or household purposes
• Alteration, painting, connecting, gluing, sealing or assembly not in accordance with the manufacturer’s instructions
• Extreme storms, wind, flood, fire, overaccumulation of snow load, or other extreme weather conditions.

 

Snow Load Advisory:

 

Customers are expected to regularly clear snow accumulation from the roof of their greenhouse as overaccumulation may crush the structure.  This type of damage is not covered under this warranty.

 

Commencement and Transferability

 

This warranty commences from the date of purchase and is non-transferable. A dated proof-of-purchase must be presented upon request. Customers are advised to keep this product warranty and proof of purchase in a secure place as they will be needed to process any claims.

 

 

 

Claims Process:

 

Address your claim to the customer service department by phone or email. A photograph or sample of the defective part(s) may be required to expedite the resolution process. If needed, the customer will allow the manufacturer or its representative to access and/or examine the greenhouse and its parts at the original service location. After a claim has been settled the guarantee will continue to run to its original expiry date (the original date of purchase). Exaco will repair or replace the product at our discretion.

 

Customer Satisfaction:

 

Ultimately, we strive to make every customer happy. We will do our utmost to resolve any warranty related issues in a manner satisfactory to the customer.

 

 

Refund and Damage Policy

Refund

• We do not provide for or allow for "Buyer's Remorse" 
• We only give full credit for product received in re-sellable condition. It is assumed that no greenhouse arrives back in a re-sellable condition (based on practical experience) at a minimum most if not all packaging has to be replaced - and all to often some parts are damaged - as a result we have a minimum restocking charge of 20% for all our greenhouses - but if product is damaged - cost of damaged parts will be subtracted from the refund

 

Damage

Customers are required to accept delivery of all packages, even if a box arrives damaged. Any visible damage must be noted on the Bill of Lading at the time of delivery and reported to us promptly.

• Small Items (UPS & FedEx Shipments): If an item is damaged, customers should contact us and we will immediately send a replacement part.
• Greenhouses: Customers should take digital photos of any damage (if possible) and email them to us for review. Based on our assessment, we will either:

• • Send replacement parts immediately
  • Suggest an easy repair (minor damage to aluminum greenhouse parts is often fixable with basic tools, like pliers)
  • Offer direct compensation for cosmetic damage (typically $100 for RIGA or Victorian Greenhouses)
  • Fully replace parts with structural damage

We are committed to making sure every customer receives a high-quality product and the support they need for any issues.