Exaco Janssens Cathedral Victorian Greenhouse with Large Cupola 15 x 20 Ft

• The Janssens Cathedral is positioned as a large-format Victorian glass greenhouse — roughly 300 sq ft (ghemporium lists 298 sq ft in its spec table, ~300 sq ft in its features copy) topped with a signature Victorian cupola measuring 10'2" L x 5'4" W. The pitch is less "grow tent" and more "garden room": full-height 6'8" sidewalls plus a 12'2" peak give enough headroom to fit a dining table, seating, and floor-to-ceiling plants without stooping anywhere along the walls.
• Construction is built around a 17-gauge aluminum frame reinforced with 2 heavy-duty aluminum support struts, finished with an electrostatically applied coating for even, long-term coverage. Glazing is 4mm tempered safety glass across both roof and walls, run in full-length panels with no horizontal overlaps — this keeps the glass cleaner (no seams to trap grime) and gives an uninterrupted, floor-to-ridge view in every direction. Tempered glass is the same safety-rated glass used in home doors and shower enclosures.
• Draft control comes from rubber glazing seals throughout, which reduce rattling and keep the space quiet in wind. The cupola's horizontal framing arrives pre-welded, which simplifies assembly of what's otherwise the most visually complex part of the structure.
• Access is via two lockable entrances — a double hinged door with soft closers, plus a single sliding door — positioned with versatile placement so the layout can be planned around a patio, garden path, or preferred interior sightline.
• Ventilation is entirely passive/manual in the base configuration: 4 roof vents with spindle openers, 2 top-hung side windows (hinge at the top, so they can stay open in rain), and 2 louvre windows with automatic openers that respond on their own as temperatures climb — giving a working cross-breeze (warm air out the top, fresh air pulled in low) even when no one is on-site to open anything manually

• Aluminum framing, glazing, and rubber seals
• 2x heavy-duty aluminum reinforcement supports
• Integrated 4" base frame
• 1x double hinged door (lockable) with soft closers
• 1x single sliding door (lockable)
• 4x roof windows with spindle openers (29" x 20") — upgradeable to automatic
• 2x top-hanging side windows (29" x 39")
• 2x louvre windows (28.5" x 39") with clear Lexan winter cover sheet — auto openers standard
• Victorian ridge cresting
• Gutters + downspouts
• Hardware

Model & footprint

The Cathedral is offered as a single large-format footprint — there's no smaller/larger version in this line. It measures 15' W x 20' L, giving 298 sq. ft. of grow space, with a 12'2" peak height and 6'8" sidewall height. The signature Victorian cupola sits at the roof's center, measuring 10'2" L x 5'4" W, and lifts the interior ceiling well above what a standard ridge would allow.

Build and materials

• Brand: Janssens, distributed by Exaco, manufactured in Belgium
• Frame: 17-gauge aluminum, reinforced with 2 heavy-duty aluminum supports, electrostatically applied finish
• Frame color: Black, Bronze
• Wall glazing: 4mm tempered glass
• Roof glazing: 4mm tempered glass, full-length panels with no horizontal overlaps
• Roof pitch: 25°
• Foundation: integrated 4" base frame, stem wall compatible (Drop Door Kit required for stem wall installs up to ~30")
• Cupola framing: arrives pre-welded for simplified assembly

Ventilation and access

• Roof vents: 4x, manual spindle openers, 29" x 20" (upgradeable to automatic)
• Side windows: 2x top-hanging, 29" x 39"
• Louvre windows: 28.5" x 39" with clear Lexan winter cover, automatic openers standard (quantity unconfirmed — one source lists 2, another lists 1; needs verification before publishing)
• Misting system: included (single-source, unverified — confirm before publishing)
• Doors: 1x double hinged door, 56.75" x 70.5", lockable with soft closers and low threshold; 1x single sliding door, 29" x 73", lockable (low-threshold upgrade available)

Performance ratings

• R-value: 1.2
• Wind rating: not yet sourced for this model
• Snow tolerance: not yet sourced for this model
• Rainwater collection: integrated gutters with downspouts

Other

• Expandable: No — fixed-footprint structure
• Warranty: 15 years, limited

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 coordinating with a foundation contractor beforehand.

• Manual

Shipping is free to all 48 contiguous states, with delivery typically taking 8–13 business days from the time the order ships. The unit arrives via LTL freight on a curbside basis — liftgate service brings the pallet down to ground level, but getting it from the curb to the install site is on the buyer, so plan for 2–3 people to handle unloading and moving the crated panels into place.

Worth noting for anyone outside the 48 contiguous states (Alaska, Hawaii, or international) — shipping terms there would need to be confirmed separately, since the free shipping offer is specific to the mainland US.

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.