It’s a curious thing, but until relatively recently the UK’s forests were not renowned for good timber architecture within their confines – indeed they were not known for having anything that might be described as architecture at all, the prevailing impression being one of perfunctorily-designed storage sheds and log cabins, the latter often imported from abroad.
Slowly but surely, though, a change has been taking place in the forest, a sign of a shift in emphasis from silviculture as a means to producing an all-too-often low value end to more environmentally-sensitive and higher added-value educational, leisure and tourism activities.
Concurrent with this shift has been a growing awareness among forest owners and managers that these new functions need to be housed in custom-designed, all-weather facilities, and that any buildings constructed should relate strongly to the landscape they sit within. As a result, a new generation of visitor centres and other projects has begun to emerge - particularly in woodlands managed by the Forestry Commission - in which the architectural emphasis has been on maximising the use of timber in their design and fabrication. The most recent and most unusual example, an observatory, can be found at the top of Black Fell, a remote and seriously exposed location deep in the heart of Northumbria’s Kielder Forest.
Getting to Charles Barclay Architects’ competition-winning building is no easy task – the roads into the furthest recesses of Kielder can best be described as fit only for high chassis forestry vehicles and when logging is taking place the loosely gravelled and pitted tracks are transformed to deep mud. At 400mk2, Kielder is also the largest forest in the country, a man-made creation intended since its foundation in the 1920s to deliver its produce on a 50-year rotation of planting and harvesting. Its sheer size and lack of population also mean it has the least light-polluted night sky in the north of England, and at Black Fell the darkest sky of all, a glittering wonderworld for practitioners of astronomy.
Being so isolated, the building also has no neighbours towards which it has to tug a forelock, and the architecture delivered by Charles Barclay has deliberately drawn on other references for its striking imagery. Barclay refers to the observatory structure as "a pier in the landscape", but also makes mention of the forest’s original purpose to produce pit props for the region’s now deceased coalmining industry and of the railway system that once permeated the country and of the archaeology of timber structures in the area that it left behind. With these images fixed in the mind, the iconography of the new building becomes clearer and the decisions regarding its structure and cladding elevated above the economic and the merely practical.
Not that this is an expensive building; the original budget was spectacularly low – at under £450,000 including the telescopes and the mechanisms that rotate the two observation turrets, the project finances have been well husbanded. This is especially true when the remoteness of the site is considered alongside the difficulty of finding local contractors prepared to price such an unusual design. The latter was solved by Stephen Mersh, a London contractor acquaintance of Barclay, who recognised the constructional challenge involved and rose to it with commendable enthusiasm and a team of locally-employed carpenters.
The building itself is relatively simple in both concept and form – a series of 3m-deep concrete pads are set into the incline of the hillside and support 10 pairs of Douglas fir columns braced with cross beams of the same species. Galvanised steel cross-bracing fixed longitudinally and transversely connects the steel column heads to the metal shoes that are bolted to the concrete footings. This substructure supports the "pier’s" deck and the 41m-long superstructure above – a long, low European larch-clad enclosure that is oriented towards another of the Kielder landscape’s artworks, James Turrell’s renowned Sky Space.
Ingeniously, the upper parts of the building are set in two layers – distinguished by the change from horizontal to vertical cladding – to create a differentiation in levels between the two telescope turrets and an uninterrupted view of the sky from each. When the facility is closed, the turrets are aligned with the main form of the structure but when opened and rotated a quite different and dynamic appearance reveals itself.
Things that seem simple, of course, are often very complicated to resolve and, in the case of the observatory’s structural design, have been heavily conditioned by the variability of the prevailing wind conditions. The very opening of the turrets’ aluminium shutters affects the building’s wind loading, not to mention the problem of the overhanging weight when the turrets are rotated. The ingenious solution to the latter transfers these eccentric loads to the substructure via the stressed timber wall panels below the turrets.
In organisational terms, the observatory is simply planned – a cantilevered canopy denotes the entrance at the north-west face of the building, at which point the visitor has a choice between accessing the building and the top-lit ‘warm’ room that precedes the first turret with its 14in Meade telescope, or of traversing the open gangway to reach the main observation deck. The gangway continues via a short ramp to the other turret that terminates the structure’s south-east end and which houses the project’s 20in Pulsar telescope.
With no windows to speak of, the visitor’s initial impression of the observatory is of a sturdy, defensible structure. A clichéd, hi-tech approach to observatory design might have been expected but, instead, a far more intriguing building rooted firmly to its wild location has emerged. Once inside, the contrast between the precision engineering of the two telescopes and the rougher, but nonetheless highly engineered, timber enclosure is striking. Opportunities like this come rarely in architecture and Charles Barclay’s practice has responded with a building that stretches perceptions of what can be achieved when timber is used creatively and intelligently.
Technical information
Foundations: 3m-deep concrete pads
Main structure: 10 pairs of American Douglas fir columns with American Douglas fir cross beams. Galvanised steel transverse and longitudinal cross-bracing connects the steel column to steel shoes bolted deep into the concrete pads.
Substructure: European whitewood framing
Walls, cantilevered entrance canopy and Pulsar turret: Spruce and birch ply lining to form stressed skin timber panels
Cladding: Siberian larch
Timber Treatments: All timber treated to achieve Class 0 / class 1 fire resistance by Arch Timber Preservation
Timber Suppliers
All structural and wall panel timber supplied by MH Southern’ Cladding supplied by Vincent Timber; decking supplied by CTS Ltd
