Janssens Royal Victorian Greenhouse VI46 Review: Is the 13x20 Worth It?

The Janssens Royal Victorian greenhouse VI46 is the biggest standard Royal Victorian, at 12'7" wide by 19'11" long. For a serious grower who wants a classic glass house that will last, it is worth it. But it is a big build and needs a proper foundation. For some yards, the VI36 is the smarter buy.

We sell and support these greenhouses every week. This review covers what the product page can't: who it suits, what it really costs, and where people go wrong.

What is the Royal Victorian greenhouse VI46?

The Royal Victorian is a glass greenhouse made by Janssens in Belgium and sold in the US through Exaco. It comes in four standard sizes: VI23, VI34, VI36 and VI46. The VI46 is the biggest of the four.

It has the classic English look: tall glass walls, a steep roof, and a decorative ridge. It is built from aluminum, comes in black or green, and has a tall 6'7" side wall. Owners notice that tall wall first. You can stand and work right up to the glass.

How big is the VI46, and what fits inside?

On paper it is a "13x20." The real outside size is 12'7" wide by 19'11" long. The peak is 9'2" high and the side walls are 6'7" high.

That gives you about 250 square feet of floor. In practice, our customers usually set it up like this:

• A bench or raised bed down each long side.
• A walking path down the middle, wide enough for a wheelbarrow.
• A potting area or a few large pots (citrus, figs) at the far end.
• Hanging baskets or tall crops like tomatoes, using the extra headroom.

What comes with the VI46?

A lot of greenhouse kits sell the frame and glass, then charge extra for everything else. The VI46 includes more than most. Here is what the kit comes with, according to the manufacturer's specs:

• Glazing: 4mm tempered safety glass. The vertical walls use single, full-height panes, not small overlapping pieces that trap dirt.
• Rubber seals: the glass sits in rubber seals instead of metal clips. This helps keep drafts out.
• 6 roof windows: 3 with automatic openers and 3 with hand-turned spindle openers, which hold firm on windy days.
• 1 louvered window for low airflow, with a clear cover for winter.
• Doors: two sliding doors that work as a double door.
• Gutters and downspouts to collect rainwater.
• Misting system (you supply a garden hose).
• Base frame about 4¼" high, which sits on your foundation.

A popular upgrade is hinged doors in place of the sliding doors, sold as a single or double door. In hot climates, an exhaust fan is worth adding too.

Should you choose all-glass or the polycarbonate roof?

The VI46 comes two ways in our store: all-glass, or a hybrid with a polycarbonate roof and glass side walls. When we wrote this, the hybrid cost about $3,400 more than all-glass.

Either way, the side walls stay glass. From the garden, it still looks like a Victorian glass house. Curious why the aluminum frame matters? See our guide to wooden vs aluminum frame greenhouses.

Can the VI46 handle snow and wind?

Yes, within limits, and the limits matter. An engineering letter rates the VI46 for 25 psf ground snow load and 115 mph wind (3-second gusts).

Those ratings only apply when the greenhouse is built as the engineers assumed. That means:

• A continuous concrete beam or solid-grouted block foundation under the whole perimeter. It must be at least 8" wide and 16" tall.
• A foundation anchor at each vertical wall post, about every 30 inches (750mm).
• Knee-brace scrolls installed at every bay on the VI46.

Our guide to the most durable greenhouses for wind, snow and harsh winters compares heavier-duty options.

What foundation does the VI46 need?

This is the step most buyers underestimate. The VI46 comes with a base frame, but not a foundation.

1. Check permits. A 250 sq ft structure often needs one. Exaco can supply engineering paperwork, and site-specific stamped letters are available for a fee.
2. Pick the spot. Choose full sun, good drainage, and access for a delivery truck.
3. Pour or build the foundation. For the published ratings, use a concrete beam (at least 8" x 16") or solid-grouted block wall.
4. Check level and square. Measure both diagonals. They should match.
5. Set the anchors as shown in the assembly manual.

Some owners set the greenhouse on a low brick knee wall. It adds height and a grand look. That works, but it adds skill and cost. For full details, read our Royal Victorian foundation, anchoring and flooring guide and our general greenhouse foundation guide.

VI46 vs VI36 vs Retro VI46: which one should you buy?

Most people deciding on a VI46 are also looking at two other models. Here is how they compare.

Model	Outside size	Floor area	Roof windows	Price guide*
Royal Victorian VI46	12'7" x 19'11"	~250 sq ft	6	~$16,599 glass / ~$19,999 hybrid
Royal Victorian VI36	10'2" x 19'11"	~200 sq ft	4	~$12,599 glass / ~$17,499 hybrid
Retro Royal Victorian VI46	12'7" x 19'11"	~250 sq ft	6	~$33,429

*Prices checked in October 2026. Prices can change and sales may apply, so click the model name to see today's price.

VI46 vs VI36

Both are the same length and height. The VI46 is about 2½ feet wider. That buys roughly 50 more square feet and two more roof windows. In glass, that cost about $4,000 more when we wrote this.

Pick the VI46 for two deep benches and a roomy path, or space for a table and chairs. Pick the VI36 if your yard is tight on width or the budget matters more than the extra floor. You can read more in our review of all four Royal Victorian sizes.

VI46 vs Retro VI46

The Retro is the same footprint with a more ornate, traditional look. It uses narrower 14" glass panels, decorative solid panels low on the walls, and two hinged doors as standard. It also has a top-hung side window.

It costs roughly twice as much. You are paying for the look, not more growing space. Because the lower wall panels are solid, there is also less glass down near floor level. Choose it if the greenhouse is a showpiece near the house.

What does a VI46 really cost all-in?

The kit price is only part of the budget. Here is what to plan for:

• The kit: see the VI46 product page for today's price, in glass or with the hybrid roof. Shipping is free to the continental US.
• Foundation: a concrete beam or block wall. Get local quotes, since prices vary a lot by region.
• Assembly: free if you build it yourself, or a quote from an assembly crew.
• Permits: check with your town before you order.
• Upgrades: hinged doors, an exhaust fan, extra shelving or shade cloths.
• Heating if you want to grow through winter.

Who is the VI46 right for?

We have helped many customers choose a Royal Victorian size. The VI46 fits these buyers best:

• Serious home growers who start hundreds of seedlings each spring.
• Collectors of citrus, orchids or tropical plants who need room to grow.
• Families who want a garden room as much as a greenhouse, with space for a small table.
• Homeowners who want the greenhouse to be a centerpiece that adds to the look of the property.

How does delivery and assembly work?

We ship the VI46 free to the continental US by freight truck, curbside. Delivery is usually on an 18-wheeler, so tell us about tight roads or low wires before you order. Someone needs to be home to receive it.

You have two ways to build it:

1. Do it yourself. The kit is designed for handy homeowners, and Exaco's support team can help by phone or video call. Plan on at least two people.
2. Hire a crew. We list trusted independent assembly crews on our Assembly Crews page, including one that covers the entire US.

For a greenhouse this size, we often suggest a crew. Large glass panes are heavy, and an experienced team gets the frame square the first time.

Is the Royal Victorian VI46 worth it?

For the right buyer, yes. You get 4mm tempered glass, a tall interior, six roof vents, and a long list of included parts. Plus, it is built by a company that has made glass greenhouses in Belgium for decades.

If width or budget is tight, the VI36 gives you the same style in a smaller package. You can compare every size in our Victorian greenhouse collection.

Frequently asked questions