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  • We'll deliver any product to your home, 5 days a week and even in two working days.
  • We schedule deliveries from 8am until 6pm.
  • Free delivery is also available.
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Alpine Grandmaster Long Window Summerhouse Cabin

From £53.19 / month


In stock
Mortice lock and lockable windows
Extra tall inside
Stronger and taller double doors
16mm cladding upgrade
10 year anti rot guarantee
Fully opening windows

Disclaimer : Painted buildings are for illustration purposes only. All buildings are on their standard or pressure treated colour upon delivery.

What’s included?

  • All fixings and fittings
  • Easy to follow instructions
  • Pre-assembled panels, roof and floor
  • Extra high ridge and eaves height
  • Tall opening windows and fully braced doors, single glazed as standard.
  • Opening side windows
  • Signature mineral felt
  • Mortice lock and lockable windows

Hand Crafted

Grandmaster Alpine 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 Alpine comes with pre-assembled panels which we building house and check before it’s delivered to your door. Making the installation of Grandmaster Alpine 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 Alpine experience a pleasant one.

Insulation Upgrade

We can offer an insulation package on Grandmaster Alpine giving you even more options and possibilities when it comes to decorating your building.

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

Build Grandmaster Alpine, your way

Just like the Evolution, the Grandmaster Alpine 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 wecan upgrade you to a rubber roof protecting your outdoor building up to 50 years.


Start creating your Grandmaster Alpine today

At Project Timber, we aim to provide you with the best customer experience as possible. We want to help you find the perfect outdoor building, exactly the way you want it

Looking for a bigger, more luxurious garden summerhouse that’s practically a home away from home? Then look no further than the Alpine Grandmaster Summerhouse Cabin. There’s plenty of space for you and your guests to enjoy the warm UK summer from the comfort of your garden. Wide spacious windows will allow plenty of sunlight to enter the building, and the extra tall inner structure will make you feel like you’re right at home. With lots of customisable options, your new summerhouse will be perfectly suited for your outdoor space.


High quality materials

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


10 Year anit rot guarantee

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


Longer lasting

Our buildings are designed to last.


Thicker and doubled up framing

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


11mm and 16mm Shiplap options available

Choose between 11mm and 16mm shiplap.


Extra high ridge and eaves height

Extra Tall Building


Optional Side Windows

Optional long side windows for 1 or both sides


Double summerhouse doors

Ease access


Long fixed windows as standard. Upgrade to opening windows

Upgrade to opening windows


Insulation option available

High performance multi-foil interior lining for maximum heat retention.


Alpine roof style with an overhang

Roof Style with overhang


Multipule sizes available

Different Sizes available


Roof Material

Our signature mineral felt is included as standard


All weather protection

Upgrade to roof shingles or Rubber Roof for maximum protection.


Fixings and Instructions

All fixings and stage by stage instructions included

Select Size
Select Measurements
Overall Dimensions
Overall Width
Overall Depth
Width Internal
Depth Internal
Eaves & Ridge
Eaves Height Inc. Floor
Eaves Height Excl. Floor
Ridge Height Inc. Floor
Ridge Height Excl. Floor
Eaves Height Internal
Ridge Height Internal
Shed Type
BillyOh Range
Roof Style
Fixtures & Fittings
Cladding Style
Locking System
Interchangeable Windows
Basecoat Treatment
Pre-Assembled Side Panels
  • Size
    Please Select..
  • Wall Thickness
    Please Select..
  • Panel & Windows
    Please Select..
  • Floor
    Please Select..
  • Door Glazing
    Please Select..
  • Roof Cover
    Please Select..
  • Insulation
    Please Select..
  • Internal Cladding Board
    Please Select..
  • Building Assembly Service
    Please Select..
  • Insulation Assembly Service
    Please Select..
  • Roof Shingle Assembly Service
    Please Select..
  • Rubber Roof Assembly Service
    Please Select..
  • Internal Cladding Board Assembly Service
    Please Select..
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