Forest Xtend 2.5 Insulated Garden Office 2.54m x 2.9m

The Forest Xtend 2.5 (XTEND2.5HDBUN) is a fully insulated SIP-built garden office measuring 2.54m x 2.9m externally (roughly 8ft x 10ft). Internal floor space is 2.17m x 2.15m enough for a proper desk setup, storage and more. It is a serious alternative to a home extension.

97mm SIP walls give a total wall thickness of 177mm when you include the 15mm tongue and groove external cladding and internal MDF lining. The 108mm SIP floor and 122mm SIP roof mean the whole building is insulated top to bottom. Outside, a 1.2mm EPDM rubber membrane covers the pent roof rated for 50 years. Anthracite grey fascias finish the look.

A double-glazed uPVC door with a 7-point multi-lock and Ultion three-star security barrel keeps your kit safe. Two full-length double-glazed windows flood the room with natural light. The 28mm wall battens and 45mm roof battens leave cavities ready for electrical wiring and recessed lighting fitted by a qualified electrician.

This building carries a 15-year structural guarantee and an energy rating of 78 (category C). It works all year round and arrives pre-cut for straightforward assembly.

The Xtend 2.5 is built from Structural Insulated Panels 97mm SIPs made from 75mm polystyrene sandwiched between two OSB sheets. The same SIP system is used for the 108mm floor and 122mm pent roof giving full envelope insulation. External cladding is 15mm kiln-dried tongue and groove timber. Internal walls and ceiling are lined with pre-primed MDF on 28mm battens creating a wiring cavity. The roof carries a 1.2mm EPDM rubber membrane rated for 50 years. All glazing is 28mm A-rated double glazed toughened safety glass in uPVC 5-chamber frames. Total wall thickness reaches 177mm.

Structure: SIP panels with OSB facing and 75mm polystyrene core. External cladding: 15mm kiln-dried tongue and groove timber. Internal lining: pre-primed MDF on 28mm battens. Floor: 108mm SIP panel left unfinished. Roof: 122mm SIP panel with 1.2mm EPDM rubber membrane. Glazing: 28mm double glazed toughened safety glass in uPVC 5-chamber frames.

A solid level base must be in place before delivery or installation. A concrete slab or level paving is suitable. The buyer is responsible for preparing the ground. No base is supplied with the building. The floor is delivered as an unfinished SIP panel the buyer adds their own floor covering on top.

The Xtend 2.5 arrives as pre-cut modular SIP panels ready to assemble. Fixtures, fittings, exterior fascias and a step-by-step installation guide are all included. The panel system is designed for straightforward self-build. Forest also offer a professional installation service if you prefer not to build it yourself. Two or more people are recommended for handling the panels safely.

Forest offer a professional installation service carried out by expert fitters. A solid level base must be ready before the fitting date base preparation is not included. Electrics and other accessories are also excluded from the installation service. Contact Forest for scheduling details.

Forest do not supply an electrical service. The 28mm wall battens create a cavity sized for routing cables and the 45mm roof battens leave space for recessed lights. All electrical work must be carried out by a qualified electrician. Wiring is not included.

Treat the exterior timber cladding on assembly and every year after that. Suitable products include Sikkens Cetol HLS Plus, Restol Wood Oil and Osmo Country Colour. Annual treatment is required to keep the 15-year structural guarantee valid. The EPDM roof covering is maintenance free. Clean glazing as needed and keep gutters and roof edges clear of debris.

The internal floor space is 2.17m x 2.15m just under 4.7 square metres. That fits a full-size desk and chair with room for shelving or a small storage unit alongside. It works well as a single-person home office or a focused creative studio. You could also set it up as a hobby room with a workbench. It is tight for gym equipment but a compact exercise bike or yoga mat fits fine. The full-length windows and insulated walls make it a practical year-round workspace rather than a seasonal shed.

Most garden offices in England fall under permitted development if they are single storey and do not cover more than half the garden. This model has a 2.5m ridge height and 2.4m eaves height which typically sits within permitted development limits. Rules differ in Scotland, Wales and Northern Ireland. Always check with your local planning authority before you build this is not legal advice.