Cathedral Greenhouse By Janssens

Description

The Janssens Cathedral is the most dramatic single-model structure in the Janssens range — a premium glass outdoor room defined by its soaring roofline, distinctive central cupola, and the kind of vertical presence that turns a backyard into an estate. At nearly 300 square feet with a 12’2” peak height and 6’8” sidewalls, it offers an interior volume that feels cathedral-like in every sense: luminous, expansive, and genuinely inspiring. Whether used as a landmark residential entertaining space, a hospitality venue, or a year-round private retreat, the Cathedral makes an architectural statement that outlasts every season.

The structure is built around a 4mm tempered glass and 17-gauge tubular aluminum frame with heavy-duty portal frame supports — construction designed to maintain its structural integrity through decades of outdoor use. A 25-degree roof pitch and a full ventilation suite — four roof vents, two push-out side windows, and two louvre windows — provide a climate-controlled interior that performs year-round. One set of double hinged doors and one sliding door offer flexible access from multiple entry points, and frame colors in Black (RAL9005) and Bronze (RAL7006) allow the Cathedral to complement both contemporary and traditional property aesthetics.

Designed and engineered in Belgium by Janssens and backed by a 15-year limited warranty, the Cathedral is available with an extensive range of optional upgrades including shelving, additional ventilation, and climate control systems.

Lead Times: 2–12 weeks depending on US inventory and any custom selections.

Payment Policy: Your card is not charged until a delivery window is confirmed, typically within 1–2 business days.

Specifications

Dimensions

Footprint: 19’ 11” L × 15’ W (approx. 298 sq. ft.)

Peak Height: 12’ 2”

Sidewall Height: 6’ 8”

Roof Pitch: 25 degrees

Frame & Glazing

Glazing: 4mm tempered safety glass panels

Frame: 17-gauge tubular aluminum with heavy-duty portal frame supports

Frame Colors: Black (RAL9005) | Bronze (RAL7006)

Architectural Feature: Signature central cupola roofline

Ventilation & Access

Roof Vents: 4 roof vents

Side Windows: 2 push-out side windows

Louvre Windows: 2 louvre windows

Doors: 1 set double hinged doors + 1 sliding door

Inclusions & Pricing

Standard Accessories: Gutters with downspouts

Optional Upgrades: Shelving, climate control, additional doors, extra ventilation

Price: $45,999

Warranty: 15-year limited warranty

Origin: Manufactured in Belgium

Why You’ll Love It

Nothing Else in the Garden Comes Close.

The Cathedral’s cupola roofline and 12’2” peak height create a visual impact that goes well beyond a standard glass structure. From the garden, it reads as a landmark. From inside, it feels like a room designed around light itself. This is the structure that defines the property it sits on.

An Interior That Inspires.

At nearly 300 square feet with 6’8” sidewalls and a soaring peak, the Cathedral has room for a full entertaining layout, a lounge area, a bar setup, or any combination of uses the occasion demands. The vertical volume and abundant glazing keep the interior bright, open, and genuinely uplifting year-round.

Climate Control That Matches the Scale.

Four roof vents, two push-out side windows, and two louvre windows give you precise control over airflow throughout the Cathedral’s generous footprint. A 25-degree roof pitch sheds rain efficiently and the 4mm tempered glass delivers the thermal performance a space this large requires.

Two Entry Points, Total Flexibility.

A set of double hinged doors and a separate sliding door mean the Cathedral accommodates catering, events, large furniture, and high-traffic entertaining without any bottlenecks. Flow through the space is as thoughtfully designed as everything else about it.

Make It Exactly Yours.

An extensive optional upgrade program — shelving, climate control, additional ventilation, extra doors — means the Cathedral can be configured precisely to how you intend to use it. Available in Black or Bronze frame finishes to complement any property aesthetic. Backed by a 15-year Janssens warranty.

About the Manufacturer

Janssens of Belgium is a family-owned greenhouse company with more than 75 years of horticultural engineering expertise. Founded in 1946, Janssens has earned an international reputation for producing glass structures that set the benchmark for quality, precision, and longevity. Their structures are TUV and GS certified for safety and are engineered to perform in extreme conditions — high winds, heavy snow, and intense hail — making them a trusted architectural investment for residential and commercial properties worldwide.