I-joists take to high seas

Summary
¦ AHW Building Solutions’ modular construction system incorporates James Jones’s JJI-joists.
¦ The building comprises 30 engineered timber pods.
¦ Triboard, supplied by James Jones, was specified for the external cladding.
¦ The modules were transported to Fair Isle during a 14-day weather window.

Time has been of the essence right from the start of the project to construct a new, £4m, 1,500m², mainly timber, bird observatory on Fair Isle. In addition to all the usual “on time and on budget” requirements, there were a few other factors to consider.

“The new Fair Isle Bird Observatory (FIBO) replaces an earlier 40-year-old structure, which was demolished to make way for the new one,” said project director Ian MacGillivray of lead designer Synergie Scotland. “The client, Fair Isle Bird Observatory Trust, was keen that the observatory should be ‘closed for business’ for only one season. This would have been impossible using traditional construction methods, particularly given the short building season Fair Isle’s weather dictates, so we decided to use a modular system instead.”

For this system Synergie worked with AHW Building Solutions of Kirkwall, Orkney, which has developed and manufactures its own engineered timber, full panel, modular construction system, incorporating James Jones & Sons’ FSC-accredited JJI-Joists as principal structural elements.

FIBO is an innovative, sustainable, largely timber two-storey modular building. Designed to bring previously existing facilities up to the standards expected by today’s visitors, the new Observatory building includes a permanent house for the warden and his family as well as bird-watching, commercial, conferencing, catering, retail and accommodation facilities.

Severe weather

Specially designed to withstand Fair Isle’s severe weather conditions, the building comprises 30 engineered timber pods, constructed from closed panels, fitted with the innovative Energyflo wall insulation system, which enables warm air to circulate in the

cavity and be recovered using a heat pump. Floors, ceilings and walls use JJI-Joists extensively, which, said Mr MacGillivray, “provided an A-rated green material to maintain the building’s sustainable credentials”.

The roof uses glulam beams, allowing large span openings where modules were joined.

Cladding was key

Given the exposed location, external cladding for this building was key and a highly durable laminated timber product called Triboard (also supplied by James Jones) was specified for the external walls. This incorporates a layer of spruce sandwiched between two boards of Siberian larch and, in this case, was supplied in 27mm-thick, 5x2m sheets.

“Triboard was supplied to comply with the client brief for minimal external maintenance,” said Brian Robertson, general manager of James Jones Timber Systems Division. “It’s uses untreated Siberian larchwhich grows very slowly in the cold climate so it is very dense and durable – ideal if you want something low maintenance which can withstand the severest weather. And it’s highly sustainable.”

The roof is clad in Metro metal tile, plus 5kW-worth of photovoltaic tiles.

With Synergie driving the design and permissions and AHW the pod manufacture and erection services, an impressive build schedule was set – and met.

Sea transport

Eight months was spent on the funding, design and permissions process – not least of which was getting Building Control approval for the Energyflo insulation system. Work on site finally started in July last year when demolition began. This, the foundations and transport (in threes and by sea) and erection of the the 30 engineered timber pods took five months.

Despite significant delays with heavy seas and ferries having to turn back, the actual shipping and erection of the modules was successfully carried out over a 14-day weather window and the building was wind and watertight by September.

Six months remained in the contract for interior fit out and landscaping and, despite what Mr MacGillivray describes as “the major challenge of logistics when you need to transport all your supplies to an off-shore site”, the building was successfully handed over in early May this year.

• This article first appeared in the summer edition of TTJ sister title Timber & Sustainable Building. For your copy contact mjeffree@ttjonline.com.