Norbord’s SterlingOSB is taking centre stage in a ground-breaking sustainable building project for Forestry Commission Scotland. The material SterlingOSB– one of the UK’s most widely-used board products – is being used for flooring, roofing and wall panels at Forestry Commission Scotland’s new Inverness Forest District Office, in Smithton, near Inverness.

The new building, designed by HRI, was commissioned as an exemplary building demonstrating the use of home-grown and certificated timber. In keeping with the principles of sustainable forest management, the building is also designed to be environmentally sustainable and energy efficient.

The new building is constructed using a high proportion of timber which comes from the Commission's own forests. It will have a wood-fuel heating system, solar panels to pre-heat the water and it will recycle rainwater from the roof for use in the toilets. The building measures approximately 35m long by 16m wide and is 8m tall. The open-plan interior will accommodate 28 Commission staff and includes a mezzanine floor across half the width of the building with room for an additional 15 staff if required.

The Commission itself has supplied the large Douglas Fir timbers used to construct the structural frame and roof trusses. Indirectly, it has also supplied the material for the walls, floors and roof panels. These elements of the building are all made using Norbord’s SterlingOSB.

SterlingOSB is manufactured at Norbord’s Inverness factory, less than three miles from the site of the new Commission office. Furthermore, up to 60% of all Norbord products are made using timber from Commission forests. Hence SterlingOSB was an obvious choice for this project, having been grown and processed within a very small radius of its final use.

“We supplied over 1,000 square metres of tongue-and-grooved and square-edged SterlingOSB for the walls, floors and roof of the building, and also for the construction of a mezzanine floor” says George Wilson, Sales and Technical Manager at Norbord Cowie.

SterlingOSB boards are normally distributed via builders merchants, and most of the OSB supplied to this project was ordered via Travis Perkins Inverness. However, SterlingOSB is also a primary component within a number of manufactured products which were also specified for this project.

“The timber I-beams used in the roof and mezzanine were made by James Jones of Forres, very near Inverness” says Stefan Brown, site manager for main contractor MMC Miller. “The web in these joists is made of SterlingOSB board” he adds.

The variety of applications to which the material is put illustrates the versatility of the product and the building’s environmental credentials underline SterlingOSB’s qualities as a sustainable building product.

The raw material for SterlingOSB is forest thinnings, the normal by-product of sustainable forest management. As softwood plantations grow to maturity, they need thinning out so that the best specimens have space to grow to their maximum height. It is from mature trees like these that the Commission has taken the large timbers for the frame of its new building.

The thinnings – small trees unsuitable for sawing into logs – form the raw material for SterlingOSB. After the branches and bark are removed, the trunk is shaved into wafer-thin strands which are then blended with resins and formed under pressure into boards. The orientation of the strands, or wood fibres, give the board its superior dimensional strength as well as producing a consistent, homogenous texture and density throughout the board.

When the office is completed later this year the exposed internal timbers and external larch cladding will reflect the importance of timber in its construction. However, very little of the SterlingOSB will be visible. “The internal walls will be clad with plasterboard and the external walls with larch”, explains Mr Brown. “But under every surface there will be SterlingOSB”.