Grandmaster Duke Summerhouse - Pressure Treated |
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FREE NEXT DAY DELIVERY
on selected postcodes*
15-YEAR ANTI-ROT GUARANTEE
Terms and conditions apply
FREE PRESSURE TREATMENT
on selected products*
0% APR
with £0 deposit

Disclaimer : Painted buildings are for illustration purposes only. All buildings are in their standard or pressure treated colour upon delivery where the colour may vary from those shown. Adequate distance must be kept between the boundary and your building to allow access to apply the annual treatment to comply with the anti-rot guarantee*.

What our customers say

  • James, Merseyside
    "Fantastic communication and great service. Excellent quality shed. Would highly recommend."
FREE NEXT DAY OR PICK A DATE DELIVERY ON CHECKOUT

Grandmaster Duke Summerhouse – Pressure Treated

Free Anti-Rot Treatment - Guaranteed for 15 years*
  • Extra STRONG
  • EXTRA TALL
  • UK Manufactured By Us
  • Multiple Design Options
  • Fully Pressure Treated*
  • Free UK Delivery*
  • Assembly time is 4x faster than a log cabin!
  • Shatter Resistant Styrene Glazing

For 10% discount use code SPRING10

1 Choose your treatment

  • Standard Dip Treatment
  • FREE PRESSURE TREATMENT
    WORTH £430
In stock
Mortice lock and lockable windows
Extra tall inside
Stronger and taller double doors
16mm cladding upgrade
15 year anti rot guarantee
Fully opening windows

2 Choose your size

Increase your interior space with our larger sizes.

  • 8 x 10
    8 x 10
    £1,799 £1,619
  • 10 x 8
    10 x 8
    £1,799 £1,619
  • 12 x 8
    12 x 8
    £1,999 £1,799
  • 10 x 10
    10 x 10
    £2,099 £1,889
  • 12 x 10
    12 x 10
    £2,299 £2,069
  • 16ft x 8ft pressure treated duke grandmaster summerhouse
    16 x 8
    £2,499 £2,249
  • 12 x 12
    £2,699 £2,429
  • 16ft x 10ft pressure treated duke grandmaster summerhouse
    16 x 10
    £2,999 £2,699
  • 16ft x 12ft pressure treated duke grandmaster summerhouse
    16 x 12
    £3,399 £3,059
  • 20ft x 10ft pressure treated duke grandmaster summerhouse
    20 x 10
    £3,699 £3,329
  • 20ft x 12ft pressure treated duke grandmaster summerhouse
    20 x 12
    £4,299 £3,869

20 x 12

20ft x 12ft pressure treated duke grandmaster summerhouse
£4,299

4 Choose your window fixings

Please note: UPVC will increase the lead time of the building. Please contact us before placing your order.

Details

X

  • Economy Fixings

    Our economy silver fixings are butt hinges that are suitable for our single styrene glazing option. The opening windows are top hung where they also come with silver casement stays as standard.

  • Premium Fixings

    Our premium brass hinges are more heavy-duty and can easily support the weight of our double glazed windows and doors. They are also supplied with brass casement stays. You can still choose to have our brass fixings with our styrene glazed windows and doors if you are looking for a more premium finish.

  • UPVC Fixings

    Our UPVC fixings are only available with our UPVC window option. Please select the UPVC Fixings to select our UPVC options in our three colour choices.

  • Economy Fixings - Top Hung Windows
    £0
  • Premium Fixings - Side Hung Windows
    £125
  • UPVC Fixings
    £130

5 Choose your window and door material

Please Note: Our Styrene Standard Modern Single Glazed windows and doors are for seasonal use. Should you want to use your garden building all year round, please upgrade to our Toughened Glass Premium Modern Double Glazed windows & doors.

Please note: UPVC will increase the lead time of the building. Please contact us before placing your order.

Details watch

X

  • Single Glazed

    We offer single shatter-resistant styrene glazing as standard on our timber windows and doors. Styrene glazing is a more seasonal option but also more cost-effective if you are only planning to use your building in the warmer months.

  • Double Glazed

    For a building you can use all year round, you can upgrade to our double glazing option for your windows and doors. Our double glazing is made from 4mm toughened glass with a 6mm cavity. This option also provides better security compared to our single styrene glazing. We also recommend that you upgrade to our premium brass fixings if you choose to have double glazing on your building

  • UPVC Windows and Doors

    For the ultimate garden building that you can use all year round, we offer our premium quality UPVC windows and doors. Our UPVC option offers increased security with a deadlock locking system on our doors, and also comes double glazed with toughened glass as standard. This helps lock in the temperature, which is perfect if you are planning on insulating your building.

6 Choose your floor

Upgrade to a thicker and stronger floor for heavier items.

Details watch

X

  • 11mm Floor

    Pressure treated 11mm tongue and groove Floor Boards. Standard option.

  • 19mm Floor

    Pressure Treated 19mm tongue and groove floor boards - select this option for medium use, if you intend on having furniture in the building and using occasionally.

  • 28mm Floor

    Pressure Treated 28mm tongue and groove floor boards. Select this option for Heavy use. This may include Gym/ heavy furniture use or heavy all year round use.

  • 11mm Floor
    £0
  • 19mm Floor
    £475
  • 28mm Floor
    £1,062

7 Choose your roof cover

Details watch

X

  • Roof Covering Option - Mineral Felt

  • Coloured Felt Tile - Black

  • Coloured Felt Tile - Green

  • Coloured Felt Tile - Grey

  • Roof Covering Option - Rubber Roof

  • Mineral Felt
    £0
  • Black Felt Tiles
    £345
  • Green Felt Tiles
    £345
  • Grey Felt Tiles
    £345
  • Rubber Roof
    £1,477

8 Choose your guttering

Details watch

X

  • Guttering

    Adding guttering to your building is a great way to help reduce any water run-off down the sides of your building. This can help prevent any moisture ingress and any water pooling around your building, especially in particularly damp or exposed areas. You can also use your guttering to collect rainwater with a water butt, which is ideal if you have a lot of plants and need a lot of water during the dryer summer months.

    Our guttering option on an Apex roof building gives you guttering for both sides, whereas on a pent building you will only require guttering for the back of your building due to the mono-pitched roof.

  • None
    £0
  • Guttering
    £296

9 Choose your paint colour

Please note the colours are not pre-painted on the product before delivery, and are supplied in tub of paint.

Details

X

  • Doormouse

    Doormouse Paint

  • Doulting Stone

    Doulting Stone Paint

  • Foxwhelp Red

    Foxwhelp Red Paint

  • Goblin Blue

    Goblin Blue Paint

  • Moreland Green

    Moreland Green Paint

  • Rock Rose

    Rock Rose Paint

  • Sedge Green

    Sedge Green Paint

  • None
    £0
  • Doormouse Grey
    £326
  • Doulting Stone
    £326
  • Foxwhelp Red
    £326
  • Goblin Blue
    £326
  • Moorland Green
    £326
  • Sedge Green
    £326

10 Choose your colour trim

Please note the colours are not pre-painted on the product before delivery, and are supplied in tub of paint.

Details

X

  • Swan White

    Swan White Trim Paint

  • Chantry Cream

    Chantry Cream Trim Paint

  • None
    £0
  • Swan White
    £63
  • Chantry Cream
    £63

11 Choose your silicone gun set

X

  • Silicone Gun Set

    If you wish to fully seal any parts of your building, such as if you have double glazing or uPVC windows and doors, our Silicone Gun set comes with a Silicone Gun and a tube of sealant so you can lock in temperature and also reduce the chance of any leaks over the lifespan of your building.

  • None
    £0
  • silicone gun set thumbnail
    Silicone Gun Set
    £15

12 Choose your padlock protector

X

  • Padlock Protector

    To give your building extra security our Padlock Protector helps to prevent the hinge on the hasp and staple lock from being drilled or removed. The dome cover also limits access to any padlock.

    No padlock is supplied with the Padlock Protector Lock.

  • None
    £0
  • padlock protector thumbnail image
    Padlock Protector
    £30

13 Choose your hasp and staple

X

  • Hasp and Staple

    Our Hasp and Staple Lock gives your building a simple lock for your building that is fitted to the doors and a padlock fitted to secure the lock.

    No padlock is supplied with the Hasp and Staple lock.

  • None
    £0
  • thumbnal hasp and staple
    Hasp and Staple
    £10

14 Choose your garden building toolkit

X

  • Garden Building Tool Kit

    Our 7 piece Value Toolkit gives you all the basic tools to assemble your garden building.
    Offering great value for money and all supplied in a single bundle to make assembly easier for you.

    The Toolkit contains the following:

    • Wood Saw
    • Hammer
    • Screwdriver
    • Spirit Level
    • Paintbrush
    • Gloves
    • Safety Goggles

  • None
    £0
  • Value Tool Set
    £35

15 Choose your base

All of our buildings require a solid level base. Choose from constructing your own base or select the timber base that we supply for your building size.

X

  • No Base

    Your building comes without a base as standard, where you will need to construct one from your own materials.

  • Project Timber Base

    The timber base we supply is made from pressure treated timber. It is made to measure to perfectly fit your building size.

    Some assembly is required and solid ground in the build area. Please ensure there is at least 1m clearance from any boundary on all sides.

  • None
    £0
  • Base
    £1,265

16 Choose your building assembly service

Details

X

  • Assembly Team

  • Assembly Service Postcodes

    We are currently only able to offer the service to limited postcodes – The postcodes for Assembly are AL, B, BB, BD, BL, BR, CB, CH, CM, CO, CR, CV, CW, DA, DE, DH, DL, DN, DY, E, EN, GU, HA, HD, HG, HR, HP, HU, HX, IG, IP, KT, L, LE, LN, LU, M, ME, MK, N, NE, NG, NN, NR, NW, OL, OX, PE, PR, RG, RH, RM, S, SG, SK, SL, SM, SN, SR, SS, ST, SW, TF, TS, TW, UB, W, WA, WD, WF, WN, WR, WS and YO. If you are outside the above postcodes we may be able to assemble at an extra charge.

    Call us for more information.

  • None
    £0
  • Building Assembly Service
    £2,160

£4,299

  • Wall Thickness, Window Fixings, Window and Door Material, Floor, Roof Cover, Paint Colour, Colour Trim → Please choose an option.

Available for delivery in 5-10 working days.

  • Window and Door Material → updating options…

Disclaimer : Painted buildings are for illustration purposes only. All buildings are in their standard or pressure treated colour upon delivery. A distance of 1m must be kept between the boundary and your building to allow access for annual treatment and to comply with the anti-rot guarantee*.

High Quality Materials

Thicker & doubled up timber framing with shiplap construction.

15 year Anti Rot Guarantee*

Pressure treated to protect against fungal decay and rot.

Fits through a standard door

Modular sections that fit through your door and make assembly easier.

Hand Crafted

Grandmaster is built by our fully trained product assembly team using hand-selected graded scandinavian slow grown timber at our facility in Nottinghamshire, in the cusp of Sherwood Forest.

All of products are picked, checked and packed for delivery making sure everything meets our high standards.

We do the hard work for you

Grandmaster comes with pre-assembled panels which we build in house and check before it’s delivered to your door. Making the installation of Grandmaster easier for you or your installer, whilst saving you time and money.

Alongside this we have created a set of easy to follow instructions which are sent out with every building, making your Grandmaster experience a pleasant one.

Build Grandmaster to your specification

The Grandmaster is built up of modular panels. Meaning that you can customise your building to your needs. Choose from base-coated or pressure treated finsh which comes with a 15 year anti-rot guarantee*. Upgrades from external cladding thickness (11mm or 16mm) to flooring thickness (11mm, 19mm or 28mm) providing a stonger base for heavier applications. You have two glazing options with Grandmaster the first being styrene forseasonal use or double glazing to enjoy your Grandmaster all year round. For extra protection we can upgrade you to a rubber roof protecting your outdoor building up to 50 years.

Free Delivery

Free Delivery

On selected postcodes

30 Days Returns

30 Days Returns

no-hassle returns

Made in our facility in Nottinghamshire

Made in our facility in Nottinghamshire

in the cusp of Sherwood Forest

Choose from one of the sizes we offer. Our Traditional Windowed 2 Doors Grandmaster Workshop Shed comes with the following as standard –
 
Included
 

High quality materials

We only use the very best materials for our garden buildings.
 
Included
 

10 year anti-rot guarantee

Peace of mind that your building will stand proud for years.
 
Included
 

Longer lasting

Our buildings are designed to last.
 
Included
 

Thicker and doubled up framing

27mm x 44mm panel framing – thicker than standard. Key supports are doubled up to 54mm for extra support.
 
Included
 

Fully braced doors

  • Open fully for extra comfort
  • Extra high for more headroom
  • Fully braced for increased strength
 
Included
 

Mortice lock and lockable windows

Extra high security with a three lever lock to keep your belongings safe.
 
Included
 

Extra tall interior

  • 2.3m ridge height for 8ft range
  • 2.4m ridge height for 10ft / 12ft
  • Room for taller items
  • A comfortable space for all day use
 
Included
 

Extra strong, double sided roof trusses

Extra support to maximise the roof strength.
2

Thickness

Easy and strong tongue and groove construction

Our shiplap panels keep rainwater and other harsh elements from entering the building. This is primarily due to its construction where the panels closely interlock, leaving no space for water penetration and weather damage.
Included
 

11mm shiplap

Tongue & groove

Upgrade

16mm shiplap

Tongue & groove

3

Floor

Included
 

11mm floor

Tongue & groove

Upgrade

19mm floor

Tongue & groove

Upgrade

28mm floor

Tongue & groove

5

Roof cover

A choice of roof covers for your preference and budget

Included
 

Mineral felt

Upgrade

Black roof tiles

Upgrade

Grey roof tiles

Upgrade

Green roof tiles

Select options
SCROLL UP TO SEE YOUR BUILDING
  • Size
    Please Select..
  • Wall Thickness
    Please Select..
  • Window Fixings
    Please Select..
  • Window and Door Material
    Please Select..
  • Floor
    Please Select..
  • Roof Cover
    Please Select..
  • Guttering
    Please Select..
  • Paint Colour
    Please Select..
  • Colour Trim
    Please Select..
  • Silicone Gun Set
    Please Select..
  • Padlock Protector
    Please Select..
  • Hasp and Staple
    Please Select..
  • Garden Building Toolkit
    Please Select..
  • Base
    Please Select..
  • Building Assembly Service
    Please Select..
        


            

                   
                
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