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10x20 Janssens Master Victorian Greenhouse Black

  • 10ft 2" wide x 19ft 10" deep
  • 4mm Full Length Toughened Safety Glass
  • Extra Strong Black Powder Coated Aluminium Frame
  • Double Sliding Doors
  • 4 x Roof Vents
  • 11 Blade Louvre Vent
  • Includes Box Section Base Plinth
  • No Clip Rubber Glazing Gasket Strips
  • Roof Cresting
  • Gutters and 40mm Aluminium Downpipes
  • Stainless Steel Hardware
  • 13 Year Manufacturers Warranty
Greenhouse Size Diagram

Greenhouse Dimensions

A: Greenhouse width

3100mm (10′ 2″)

B: Greenhouse depth

6060mm (19′ 10″)

C: Ridge height

2740mm (8′ 11″)

D: Eaves height

2010mm (6′ 7″)

E & F: Door Size

700mm (2′ 3″) x 2000mm (6′ 6″) (aperture)

Minimum size for your greenhouse base:

3100mm (10′ 2″) x 6060mm (19′ 10″)

Customise your Greenhouse

More Sizes:

Select your Colour:

🛠️ Get it installed by Professionals:

Installation requires that you purchase the Base Plinth Option if one is available. You MUST have a surface of slabs, concrete or decking. NOT soil or gravel.

Get it installed by Professionals?

Installation

Please Note: Installation requires an optional base plinth (if available) on a flat, level surface like slabs, concrete, or decking that meets the minimum base size. The package includes the greenhouse, ventilation, and downpipes only; accessories and groundwork are excluded. Installation will be carried out 2-8 weeks after the delivery of your Greenhouse.

🛠️ Installation
£1,450

Add Cresting?

Roof Cresting
+ £230

Add a decorative cresting to the top of your greenhouse

Cresting information

Roof Cresting - £230.00
Roof Cresting

Add a decorative cresting to the top of your greenhouse


Add Staging?

Qty 1
Janssens Colour Matched Full Length Integrated Shelving
+ £195

Add the Silver 458cm long x 23cm wide integrated shelving to your greenhouse to help retain your floor space

Qty 1
Qty 1
Janssens Colour Matched integrated Staging
+ £110

Add the Coloured 150cm long x 53cm wide integrated staging to your greenhouse to help retain your floor space

Qty 1
Janssens Seed Tray Shelving
+ £420

Add the Silver Full Length long Seed Tray Shelving to your greenhouse to help retain your floor space

Qty 1
£10 off
£10 off
1 Tier Staging Silver
+ £69

This 1 Tier Vitavia silver greenhouse staging gives you a handy work surface and storage area. Dimensions: 76cm (H) x 50cm (D) x 120cm (W)

Qty 1
£11 off
£11 off
2 Tier Staging Silver
+ £88

This 2 Tier Vitavia silver greenhouse staging gives you a handy work surface with additional low level storage. Dimensions: 76cm (H) x 50cm (D) x 120cm (W)

Qty 1
£10 off
£10 off
Top Tier Staging Extension Silver
+ £49

This little top level silver shelf attaches to 1 or 2 Tier staging to give you a bit more storage space

Qty 1

Staging information

Janssens Silver Full Length Integrated Shelving - £149.00
Janssens Silver Full Length Integrated Shelving

Add the Silver Full Length 458cm long x 23cm Wide integrated shelving to the side of your greenhouse to help retain your floor space


Janssens Colour Matched Full Length Integrated Shelving - £195.00
Janssens Colour Matched Full Length Integrated Shelving

Add the Silver 458cm long x 23cm wide integrated shelving to your greenhouse to help retain your floor space


Janssens Silver Integrated Staging - £95.00
Janssens Silver Integrated Staging

Add the Silver 150cm long x 53cm wide integrated staging to your greenhouse to help retain your floor space


Janssens Colour Matched integrated Staging - £110.00
Janssens Colour Matched integrated Staging

Add the Coloured 150cm long x 53cm wide integrated staging to your greenhouse to help retain your floor space


Janssens Seed Tray Shelving - £420.00
Janssens Seed Tray Shelving

Add the Silver Full Length long Seed Tray Shelving to your greenhouse to help retain your floor space


1 Tier Staging Silver - £69.00
1 Tier Staging Silver

This 1 Tier Vitavia silver greenhouse staging gives you a handy work surface and storage area. Dimensions: 76cm (H) x 50cm (D) x 120cm (W)


2 Tier Staging Silver - £88.00
2 Tier Staging Silver

This 2 Tier Vitavia silver greenhouse staging gives you a handy work surface with additional low level storage. Dimensions: 76cm (H) x 50cm (D) x 120cm (W)


Top Tier Staging Extension Silver - £49.00
Top Tier Staging Extension Silver

This little top level silver shelf attaches to 1 or 2 Tier staging to give you a bit more storage space


Add Ventilation and Shading?

Qty 1
Louvre Vent
+ £140

A louvre window brings fresh cool air into your greenhouse to moderate the temperature inside. An essential add on.

Qty 1

Ventilation and Shading information

Auto Roof Vent Opener - £65.00
Auto Roof Vent Opener

This automatic opener for your roof vents will automatically open your roof vents to ventilate your greenhouse when it becomes too hot.


Louvre Vent - £140.00
Louvre Vent

A louvre window brings fresh cool air into your greenhouse to moderate the temperature inside. An essential add on.


Add Extras?

Hygrometer
+ £17

This Hygrometer will measure the humidity levels inside your greenhouse.

Soil Thermometer
+ £29

This Soil Thermometer will let you track the temperature of your soil inside the greenhouse.

Max/Min Thermometer
+ £23

This thermometer will tell you your maximum daytime temperature as well as record the lowest night time temperature in your greenhouse.

100L Mini Rainsaver Water Butt
+ £54

Add this 100L water butt kit that includes: Butt, Tap & Lid - Black Stand

Qty 1

Extras information

Hygrometer - £17.00
Hygrometer

This Hygrometer will measure the humidity levels inside your greenhouse.


Soil Thermometer - £29.00
Soil Thermometer

This Soil Thermometer will let you track the temperature of your soil inside the greenhouse.


Max/Min Thermometer - £23.00
Max/Min Thermometer

This thermometer will tell you your maximum daytime temperature as well as record the lowest night time temperature in your greenhouse.


100L Mini Rainsaver Water Butt - £54.00
100L Mini Rainsaver Water Butt

Add this 100L water butt kit that includes: Butt, Tap & Lid - Black Stand


Choose your Colour

Black Powder Coated Frame
+ £0

Green Powder Coated Frame
+ £0

White Powder Coating
+ £0

Choose your Colour information

Black Powder Coated Frame - £0.00
Black Powder Coated Frame

Green Powder Coated Frame - £0.00
Green Powder Coated Frame

White Powder Coating - £0.00
White Powder Coating

This 10ft x 20ft Janssens Master Victorian Greenhouse in Black is the top of the Janssens Helios Master range, the biggest, the best. Modern greenhouse design and materials meet old time Victorian Greenhouse styling. Roof Cresting and Finials sit along the super stiff box section roof ridge. Depending on your garden or personal preference, choose a green or black powder-coated frame.

All Janssens Master Greenhouses are built around a strong box-section aluminium frame and base, with 4mm Toughened Glass held in with proper rubber glazing gasket to take on the worse of UK weather!

  • 3100mm x 6060mm Dimensions (10ft 1" x 19ft 8")
  • 2m High Eaves
  • Aluminium Frame with Tubular and Box Section for Superior Strength.
  • Black Powder Coated Frame.
  • Box Section Base Plinth.
  • Victorian Greenhouse Roof Crestings.
  • Double Sliding Doors
  • 4mm Full Length Toughened Safety Glass
  • Rubber Glazing Gasket Strips (no fiddly clips)
  • 4x Roof Vents
  • 11 Blade Louvre Vent
  • Gutters and 40mm Aluminium Downpipes.
  • Stainless Steel Fittings.
  • Step by Step Instruction Manuals with Instructional DVD.
  • 13 Year Manufacturers Warranty.
  • Many Accessories Available - Scroll down this page.

Delivery is currently within 8 weeks for Urban Models, 10-12 Weeks for Master Models and 16 weeks for all other models to UK Mainland. Your exact delivery day will be confirmed with you at least 3 days before the day by telephone.

Please note Some Scottish postal codes are subject to delivery charges.

Optional Installation: If selected, Installation will be carried out 1-8 weeks after the delivery of your Greenhouse. The Installation Team will contact you directly to book in your installation.Our installation service requires a level concrete, slabbed, or decked area to the minimum size stated on the website. Failure to provide a suitable base area may result in you being charged for the failed installation. If you require staging or shelving assembly, you can arrange it directly with the installation team.

Greenhouse Size Diagram

Greenhouse Dimensions

A: Greenhouse width

3100mm (10′ 2″)

B: Greenhouse depth

6060mm (19′ 10″)

C: Ridge height

2740mm (8′ 11″)

D: Eaves height

2010mm (6′ 7″)

E & F: Door Size

700mm (2′ 3″) x 2000mm (6′ 6″) (aperture)

Minimum size for your greenhouse base:

3100mm (10′ 2″) x 6060mm (19′ 10″)

Palram Silver Steel Base
Included with ALL Janssens Greenhouses.

The Janssens Foundation Base eliminates the need for a full concrete foundation. Simply assemble your greenhouse and secure it with our quick 4-corner anchoring system!

Toughened Safety Glass
Premium 4mm Toughened Glass

JANSSENS delivers superior protection with our full-length 4mm toughened glass. Six times stronger than ordinary glass, it offers exceptional durability and safety. Enjoy crystal-clear views and peace of mind, knowing you're shielded by the industry's safest greenhouse glass. Polished edges ensure easy, safe assembly, letting you focus on what truly matters – your thriving garden.

Janssens Glazing Gasket
Weather-Tight Seal: Superior Protection Guaranteed

Don't let wind effect your investment with Janssens state-of-the-art glazing system. Featuring:

  • Advanced rubber strip technology
  • Unbeatable water and wind resistance
  • Seamless, long-lasting seal
Janssens Glazing Bars
Industry-Leading Strength in Every Frame

Janssens cutting-edge tubular aluminium glazing bars are among the sturdiest in today's greenhouse market. Enjoy peace of mind knowing your investment is protected by top-tier materials that outlast and outperform the competition!

Janssens Roof Ridge Profile
Built to Last: Premium Stainless Steel Hardware

Every bolt, nut, and fitting in your JANSSENS greenhouse is crafted from top-quality stainless steel to withstand the elements,

Janssens Roof Ridge Profile
Smart Water Management System Included

Maximize your growing potential with our comprehensive water control solution:

  • Efficient gutters to collect rainwater
  • Clever condensation channels to manage humidity
  • Large 40mm downpipes for rapid drainage
Janssens Instructions
Effortless Assembly at Your Fingertips

Set up your new greenhouse with ease. Every model includes:

  • Detailed step-by-step manual
  • Comprehensive assembly video
Janssens Qualicoat Powder Coating
Lasting Beauty: Premium Powder-Coated Finish

Janssens only use Qualicoat-certified powder coating on all of their Greenhouse products. This high-quality finish ensures your JANSSENS greenhouse stays stunning for years. Contact us for custom RAL colours.

Janssens Greenhouse
Janssens Greenhouses

Janssens Greenhouses were established in 1946 in Lier, Belgium and is now a super modern 6500sqm production facility equipped with the very latest high-tech automated machinery. Many years of production and the very latest design and manufacturing processes make a Janssens Greenhouse one of the best high end greenhouses you can buy today.

Janssens Greenhouse 13 Year Warranty
13 Year Warranty

Janssens greenhouses come with a 10-year warranty on the greenhouse frame. This warranty covers any manufacturing defects in materials or workmanship. However, it does not cover glass or polycarbonate. The warranty is only valid if the greenhouse is assembled according to the provided instructions.