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    10x20 Janssens Master Greenhouse

    Unleash your gardening potential with the Janssens Helios Master Greenhouse - the ultimate sanctuary for serious gardeners and growers. Featuring superior strength, wind-resistant toughened glass, and a 13-year warranty, this greenhouse is a must-have for anyone looking to elevate their gardening game.

    More Sizes:

    Select your Colour:

    Get it installed by Professionals:

    Installation requires that you purchase the Base Plinth Option above. 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. This may extend the standard delivery time by 2-4 weeks.

    Installation is only available in these postcode areas: B, BA, BB, BD, BL, BN, BS, CA, CB, CH, CO, CR, CT, CW, CV, CV, DA, DE, DE, DH, DL, DN, DY, EH, GL, GL, GU, HD, HG, HP, HU, HX, IP, KA, KT, LA, LE, LL, LN, L, LS, M, ME, MK, ML, NE, NG, NN, NR, OX, OL, PE, PR, RG, RH, SE, SG, SK, SM, SN, ST, SW, SY, TF, TN, TS, TW, WA, WF, WN, WR, WS, WS, WV, YO.

    Installation
    £1,275

    Add Staging?

    Qty 1
    Janssens Seed Tray Shelving
    + £250
    Qty 1
    £10 off
    1 Tier Staging Silver
    + £69
    Qty 1
    Janssens Integrated Silver Shelving
    + £40
    Qty 1
    £11 off
    2 Tier Staging Silver
    + £88
    Qty 1
    £10 off
    Top Tier Staging Extension Silver
    + £49
    Qty 1
    Qty 1

    Staging information

    Janssens Silver Full Length Integrated Staging - £135.00
    Janssens Silver Full Length Integrated Staging

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


    Janssens Seed Tray Shelving - £250.00
    Janssens Seed Tray Shelving

    Add the Silver Full Width 310cm long Seed Tray Shelving to the rear of 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)


    Janssens Integrated Silver Shelving - £40.00
    Janssens Integrated Silver Shelving

    Add the Silver 150cm long x 23cm wide integrated shelving to your greenhouse to help retain your floor space


    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


    Janssens Silver Integrated Staging - £80.00
    Janssens Silver Integrated Staging

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


    Add Ventilation and Shading?

    Qty 1
    Curtain Shading
    + £27
    Qty 1
    Louvre Vent
    + £79
    Qty 1
    Auto Louvre Opener
    + £40
    Qty 1
    Janssens Sunscreen Shading
    + £175

    Ventilation and Shading information

    Auto Roof Vent Opener - £39.00
    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.


    Curtain Shading - £27.00
    Curtain Shading

    Curtain shading will protect your plants from sun scorch and provide shade to moderate temperature. 6ft x 8ft.


    Louvre Vent - £79.00
    Louvre Vent

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


    Auto Louvre Opener - £40.00
    Auto Louvre Opener

    This automatic opener mechanism will open your louvre window for you when you’re not around. No need to worry about ventilation, this does it automatically for you! (Does not include louvre window).


    Janssens Sunscreen Shading - £175.00
    Janssens Sunscreen Shading

    Add the Janssens retractable shading kit for ease of use


    Add Extras?

    Hygrometer
    + £17
    Soil Thermometer
    + £29
    Max/Min Thermometer
    + £23
    100L Mini Rainsaver Water Butt
    + £54
    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


    The 10ft x 20ft Janssens Helios Master Greenhouse is the largest in the range, and a superb example of a greenhouse ideal for domestic or commercial use. At 10ft Wide it`s really practical. Then add in the 20ft length and you have a greenhouse for the serious gardener or grower. 4mm Toughened Glass is held in by rubber glazing gasket, making it very wind resistant and safe for the garden or business environment.

    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.
    • Box Section Base Plinth.
    • Double Sliding Door.
    • 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 information: Installation will be carried out around 14-21 working days after delivery. Optional Installation will only be carried out on a surface of slabs or concrete and only with the recommended base plinth. You may be charged for accessories Installation is for the Greenhouse only and does not include staging, accessories etc

    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 Base Size

    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!

    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.