Forest Garden Forest Xtend 4.0m

Insulated Garden Office / Footprint: 4.0m x 3.0m / Total Wall Thickness: 177mm / Double Glazing / ¼ Opening Window
Code: XTEND4.0HD
  • £12,299.00
  • (Select Option to see Delivery Schedules)
  • RRP: £15,319.00
Stock Availability : Usually dispatched within 24 hours
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Forest Xtend 4.0m

  • Pre-cut, ready for assembly, modular Structural Insulated Panels (SIPs)
  • Pre-cut interior MDF panels
  • Pre-cut external timber cladding panels
  • 97mm thick insulated walls (75mm of polystyrene insulation sandwiched by two sheets of oriented strand board)
  • Vertical Tongue and Groove Cladding - External (15mm) and Internal (9mm)
  • Total wall thickness is 177mm
  • 28mm thick Wall battens
  • 45mm thick Roof battens
  • 122mm Roof: 11mm OSB + 100mm insulation + 11mm OSB
  • External roof covering: 1.2mm thick EPDM black rubber
  • 50 years roof life expectancy
  • Floor Material: SIPs Panels (108mm)
  • Energy Efficient – EPC 78 (category C) with Potential to increase to Energy Rating of B
  • Window material: uPVC 5 chamber
  • Door material: uPVC  reinforced 5 chamber
  • Double Glazing
  • 1 x Fully Glazed Single Door
  • 2 x Full Length, Fixed Window
  • 1 x Full Length, ¼ Opening Side Window
  • Door locking: 7 point multi-lock with Ultion three star security barrel
  • Window Frame: Anthracite grey externally with grained finish Smooth white internally
  • Window locking: Two double clasp
  • Anthracite grey fascia included
  • Comes Untreated (Primer Applied)
  • Area: 106 ft²
  • Step-by-step building guide

Forest Xtend 4.0m: Rarely is functionality combined with aesthetics and craftmanship as harmoniously as in the Forest Garden Xtend range. The key asset of the Xtend buildings lies exactly in their name: they are designed as extensions of your living space. Working from home has never felt more natural thanks to the quality and comfort provided by the Xtend line, and having a separate working space of such high specification will add to your motivation and freedom. If you decide to use your Xtend building for leisure, you won’t be disappointed either. Anything, from an atelier to a luxuriant guesthouse to a garden library will not only look great, but also feel right. The Xtend 4.0m will enrich your lifestyle and promote your well-being. The first thing you’ll notice in your Xtend is the visual impact of its modern architecture, which translates into straight lines, a sleek pent roof with overhang, anthracite grey frames and fascia, and vertical elements such as floor-to-ceiling windows and vertical cladding. The building features walls at an impressive 97mm thickness. This is due to the 75mm polystyrene insulation sandwiched by two sheets of OSB. Add to this the Structural Insulated Panels, the internal and external cladding and cavities and you have a whopping 177mm total wall thickness! Similarly, the insulated roof is 122mm thick, and further adding to the energy efficient elements, the building features 28mm double glazing. Keeping you cool in summer and warm in winter, the Xtend is a dream garden building made for actual all-year-round use, and a proper extension of your living square footage at an affordable price. The ridge height, thoughtfully designed at 2.5m, means that you won’t be needing a special planning permission to build your Xtend. For your peace of mind, the building comes with a fifteen year structural guarantee.

Forest Xtend 4.0m Specifications

  • Overall Size (Inc Overhang): 404cm (W) x 342cm (D) x 250cm (H)
  • Footprint: 404cm (W) x 304cm (D)
  • Ridge Height: 250cm
  • Eaves Height: 235cm
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Click below for Delivery Information in Relation to Coronoavirus:
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Most of our items are delivered to England and Wales free of charge if the item / order value is over £50.00* however If the item is under £50.00 there will be a £5.00 delivery charge added in the shopping basket
Where Products of below £50.00 in value are shown as having Free Delivery this means when aggregated with other products to achieve minimum order value of £50.00

Exclusions from free delivery include products supplied by Burbage Irion Craft and The Pot Co which will always incur a one off delivery charge no matter how many items ordered in that consignment. Please enter your postcode in the basket for more information.

*Owing to carrier charges with certain suppliers there may be parts of the UK where an additional delivery charge may be added to the order, we will let you know if this is the case either in the basket or by email. We DO NOT seek to profit from delivery charges but simply cover carrier costs to more remote locations.

Remote locations include (but are not limited to) Scottish Highlands, remote areas of Wales which may have a delivery charge added. This depends on the product and the location.

Please note: For Scotland deliveries certain ranges will have a rather extended lead-time.  As a guide please add upto 1 week to delivery guideline.

To check if any delivery charges apply to your order please add the item/s to the shopping basket and click on the link.

If you select to pay via the personal finance option the goods MUST be delivered to the billing address which will be the address that is verified on the finance application form.

Certain Product Ranges have a Flat Rate Delivery Charge for example: The Pot Co planters and decorative pots, Satu Bumi plant pots.

Please Note: all fencing and trellis has a minimum order quantity of 3 panels, this is because of how the panels are delivered and unfortunately is non negotiable. It is not required that 3 of the same size panels be ordered, panels can be mix and match however all 3 panels must be from the same manufacturer i.e. Grange or Forest Garden, for example you could not order 2 x Grange panels and 1 x Forest Garden panel in the same order. For further information or if you are in doubt please contact us prior to placing an order.


*Owing to carrier charges with certain suppliers there may be parts of the UK where an additional delivery charge may be added to the order, we will let you know if this is the case.

With manufacturers including (but not limited to) Shire, Storemore Mercia and others there will always be a delivery charge into Scotland.


All delivery estimates stated are in working days, delivery schedules are not guaranteed and are intended as a guide only. Delivery will be made to you as soon as possible after your order has been accepted.

Orders placed during a weekend where next day delivery is stated will usually be delivered on the following Tuesday. We do not usually deliver on a weekend. Bank Holiday Weekends: Next Day Delivery Orders received over a bank holiday weekend will usually be delivered on the following Wednesday. No deliveries are made between Christmas and New Year.


Unfortunately at present we do not offer delivery to any Islands including Scottish Islands, Channel Islands, Isle of Wight, Isle of Man or to Northern Ireland. However in certain circumstances we could look to provide you with packaging sizes and weights should you wish to arrange your own onward shipping from a Great Britain mainland address, unfortunately collection from the manufacturer is not always possible for insurance reasons -Please be aware that the goods are considered as delivered once they reach your choice of shipping company, we are unable to send spares or replacements outside of UK Mainland so please endeavour to have the goods checked before the are sent for onward shipping.  Please note: If goods are ordered using our Finance Options then we are obliged by the terms of our finance provider to ONLY DELIVER TO THE ORDERING ADDRESS.  We are not able to deliver to alternative addresses or to offer collection.

Any deliveries that are made outside of UK Mainland will always incur a charge - Please contact us for more information PRIOR to placing any order for delivery outside of UK Mainland or for orders that will be for onward shipping


Please assume that delivery of larger Items examples including Sheds, Summerhouses, Log Cabins, Greenhouses, Garden Structures, Garden Furniture, Large BBQ's etc. is to Kerb Side.  Customers are advised not to assist with off-loading. Many Delivery Drivers (but not all) will help to move items beyond the kerb but at Kerb Side goods become your responsibility. Where goods are delivered on a pallet the delivery companies do not usually remove the packaging or pallets after delivery.

If the product you have purchased has an assembly option and you choose to take this assembly service then the delivery and assembly will not usually take place on the same date. The independent assembly company will endeavor to complete the assembly within 7 working days of delivery. It is very important that all parts are checked and verified before the independent assembly company arrives to carry out the work as failure to do so could result in unnecessary delays once the company arrives

In the unlikely event that you wish to return your product any unopened non-faulty items returned by you to our premises or address of our choosing complete with packaging, manuals / instructions and any fixings within 14 days (7 Days in the case of Timber or Stone Products) of purchase may obtain a full refund. If it is required that we collect goods, we may offer that service in certain cases, however there will be a carriage cost.

The Company accepts no responsibility for any consequential loss caused to the buyer for the receiving by us or our our agents of faulty goods i.e. please insure goods that are returned to us as the liability for goods whilst in transit is yours.

If you wish to Return your product please contact us for a Returns Form via the Contact us section or Telephone 01636 858290 (Customer Services)

In all cases of return the goods must be packaged correctly. In the case of discretionary returns this means that goods must be in their original and unopened packaging. In the case of faulty returns the goods must be packaged in such a way that the carriers can handle the consignment (this usually means in a box or bag).

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