For many property developers, a fast turnaround from concept to construction is vital in making sure they maximise their returns.

The structure of a new mixed-use development in London’s über-cool Shoreditch uses solid timber laminated panels to achieve astonishing build speeds – and, in turn, deliver solid profits for the client.

Using Finnforest Merk’s innovative LenoTec cross-laminated panels, the structural shell of five-storey Fairmule House was completed in five weeks, thanks to off-site prefabrication of the giant panels at the company’s manufacturing facility in Germany. And, with panels as large as 2.7x14m, it’s no surprise the building claims to be the UK’s biggest solid timber structure.

“From start to finish, we were able to build five storeys in five weeks, which would have taken three or four times as long with a steel and brick construction,” said Jonathan Fovargue, director at Eurban Construction, a specialist design, supply and install sub-contractor. The London-based company has a partnering agreement with Finnforest Merk to use LenoTec in the UK.

As well as specifying the use of solid timber, architects Quay 2c have used a horticultural theme to think through the design of the building, named after one-time local resident Thomas Fairchild, famous for his 18th century pioneering work crossing the sweet William and the carnation to create the ‘Fairchild mule’ hybrid.

The design is certainly eye-catching, but it is the LenoTec system that really takes centre stage. As well as speed of erection, the solid timber panels tick all the right environmental boxes. They also deliver high tolerances and good thermal and acoustic properties. Walls were 115mm thick, with floor and roof panels 170mm thick. Lengths were up to 140mm but, because of the dimensional accuracy, the elements were craned into place quickly and easily.

Timber lift shaft

One innovation made possible by using LenoTec panels was that a lift shaft could also be created using timber. The architect convinced lift company Kone that it could achieve the required dimensional accuracy with an enclosure of timber panels – and construction was straightforward.

The Fairmule House development is just the latest example of a building system that has already been used for houses, apartments, schools and industrial buildings.

Jonathan Stone, Finnforest Merk’s project sales engineer, is unsurprised by the popularity of the LenoTec system. “It’s getting used more and more,” he said. “Speed is one of its biggest advantages. Windows and door spaces can be pre-cut into the panel before leaving Germany, so consequently it is very quick to put in place.”

Urban success

It is also extremely versatile and ideal for urban developments where space is a premium. Eurban, for example, often uses LenoTec on confined sites like the two-storey residential development at Carlisle Lane, in the heart of London’s Waterloo area, where it was sandwiched on all sides with only a narrow lane to the site.

“You can simply put it on the back of a crane and lift it into place,” said Mr Stone. “You can also get it with a high-quality internal finish, so it can be used as an internal surface, dispensing with plasterboard and paint.”

At Fairmule House, most of the timber panels disappeared behind wall and floor. In the residential units, the client chose to have a more refined finish applied to the ceiling panels, while in the commercial units, they were left with an industrial finish.

The entire building was clad in western red cedar and, internally, walls were finished to the client’s specification (mainly plasterboard and paint).

It is also extremely stable, as Mr Stone explained: “Because it’s a solid wall-panel system, it is extremely strong and provides excellent performance on lower-rise construction and buildings that have lots of cross-walls, schools being a perfect example. And, if anything, you probably find you can span a lot further without any lateral stability because of the stiffness of the panels.”

LenoTec is not the only system on the market. Austrian company KLH Massivholz produces a rival product, KLH, made from spruce strips that are stacked crossways on top of each other. Depending on application, three, five, seven or more layers are stacked on top of each other, up to a maximum thickness of 600mm.

Again, strength is a vital factor. The company said: “Cross lamination of the strips of wood minimises swelling and shrinkage in the board plane, while considerably increasing static strength and shape retention properties.”

It said compared to conventional timber construction products, cross-laminated timber offers new ways in terms of load transfer. “Not only can loads be transferred in one direction, but on all sides,” said the company.

With increasing attention on carbon emissions, using large cross-laminated panels also highlights the green credentials of this form of building. “LenoTec presents a significantly-reduced carbon footprint because of the volumes of solid timber used versus other materials,” said Mr Stone. “It has very little other product around it to make it work, so many people use it for its carbon storage and environmental properties.”

Sustainability advantage

Jonathan Fovargue agrees. “Timber is one of the few truly sustainable building materials we have in this industry, and this is one of LenoTec’s main advantages. It also benefits from modern construction methods: we spend a lot of time working with the architect at the design stage, while the factory in Germany cuts boards to size, reducing our time on site.

“But it is the performance that really stands out. Cutting tolerances are down to plus or minus 2mm in 10m, which means everything fits perfectly and you can get an airtight structure, unlike other systems which require a lot more attention to the details in the junctions.”

And he’s convinced that LenoTec’s popularity will continue to grow. “We started with the system five years ago and have been building projects for the last three years, and found the feedback we get from our customers is very positive.

“It is a very ‘obvious’ system in that it is easy to understand. As the Building Regulations get ever tighter in terms of acoustic and thermal performance, systems such as LenoTec and KLH will grow in interest because it is inherent in the system to have these kinds of performances.”