The Westminster pairs a half-boarded Grade A, knot-free Western Red Cedar base with tempered glass above, giving it classic greenhouse character with a bright, open interior. A steep 48° roofline and 11'1" peak height create extra headroom — good for hanging baskets, taller crops, or compact fruit trees — while also helping shed snow and letting warm air rise more freely.

Cedar naturally insulates better than aluminum, helping stabilize interior temperatures, and its preservative oils make it rot- and pest-resistant without warping. As real cedar, expect natural tone variation piece to piece, weathering to a soft silvery gray over time if left untreated.

An aluminum base frame and capping protect the structure from ground moisture and weather exposure, while precision joinery keeps it rigid and square long-term. The tall, inward-swinging lockable door has a low threshold for easier access in snow or with tools and trays. Ventilation is fully passive: automatic wax-driven roof vent openers plus louver windows manage heat and airflow without electricity.

• Cedar frame + glass panels + hardware (Grade A, knot-free)
• Aluminum base frame + capping + rubber seals
• 3mm tempered safety glass (roof + walls)
• Roof vents with automatic wax openers (qty varies by size)
• Louver windows (qty varies by size)
• Lockable hinged door + keys
• Shelving: 12" deep (2-slat) + 20" deep (4-slat), one side
• Gutters + downspouts
• Victorian ridge cresting

Build and materials

• Brand: Alton, distributed by Exaco, manufactured in the UK
• Frame: Grade A, knot-free Western Red Cedar, half-boarded design, available in Moss Green or Natural Wood
• Wall glazing: 3mm tempered glass throughout
• Roof glazing: 3mm tempered glass
• Roof pitch: 48°
• Foundation: integrated aluminum base frame, raises cedar off the ground to reduce early rot risk

Ventilation

• Automatic wax-driven roof vent openers provide hands-free heat relief as temperatures rise, no electricity required (qty varies by size)
• Louver windows feed in lower-level airflow to support circulation
• Roof vent dimensions: 23" × 23"

Performance ratings

• R-value: 0.95, 1.35 depending on glazing configuration
• Rainwater collection: integrated gutters with downspouts on the structure
• Wind/snow load ratings: not listed on the source page — flag if you have this from another retailer or the manufacturer spec sheet

Other

• Door: hinged, single, inward-swinging, lockable (+ keys), 28" × 79", low threshold for easy access
• Expandable: No
• Warranty: 10 years on frame

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

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

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.