The use of cross laminated timber is gaining popularity around the world, and Australia will soon have its own multi-level residential building constructed from structural timber to marvel at. Jonathan Green looks at the 10-storey Forte project.

We have been following the progress of Cross Laminated Timber (CLT) in Building Connection for some time. Back in June 2009 Andrew Dunn from the Timber Development Association wrote about his tour of the 9-storey Stadthaus Apartment building just north of London, while another piece in 2011 explored a second London development of 8-storeys.

The success of these – and other – developments around the world led to the belief that it was always just a matter of when, not if, we would see a CLT construction in Australia.

Last year there was some fanfare about a proposed CLT apartment block on the old Carlton & United Breweries site in the Melbourne CBD. While those plans have been shelved to next year, Lend Lease surprised a few people when they started construction on a 10-storey CLT apartment block in Victoria Harbour, in Melbourne’s Docklands precinct.

This development – called Forte – will be the tallest modern timber residential building in world.

While the announcement that Forte had begun construction did take some people by surprise, it was by no means a rushed decision. While construction with CLT is exceptionally quick (Forte is hoped to be completed by October), Lend Lease spent more than four years investigating its merits before committing to the system.

“Any innovation in the building industry has to begin somewhere, and quite often it is actually borne from a problem,” says Lend Lease head of operations, Daryl Patterson.

“In this case, the ‘problem’ started with the conditions at Victoria Harbour. We were working on a number of different developments in the area, trying to deal with the classic sub soil conditions of the Yarra River with its Coode Island silt which has a pretty poor load-bearing substrate.

“The issue for us is that we still have a reasonable amount of development to go in the area – and the further we progress, the deeper the bedrock is and the strip of land we’re working on gets narrower. So our forward planning was telling us that it was going to get very expensive to construct in the same manner on what was essentially a narrow strip of mud.”

Naturally, Lend Lease started exploring lightweight construction systems. The initial discussions revolved around a traditional timber framing approach; however the thought was that it would limit the construction to only a few levels.

“I had a folder on my desktop of new construction systems, and there are plenty going around in various stages of development,” says Daryl.

“We started with literally hundreds, and carefully narrowed it down to roughly 10. We were mindful that we also wanted a system that was going to be very safe to construct and unfortunately a number of the lightweight systems out there were quite complicated and that can increase risk on site – so that ruled a few out.

“Equally, we had another consideration of sustainability and the increasing requirements on energy management and the thermal performance of the building envelope. A number of the European systems are well advanced on us, and we were mindful that we needed to address that for ourselves and for the occupants when they move in.

“These combined elements made the concept of timber and CLT very attractive.”

In very simple terms, CLT is effectively precision-made jumbo plywood. Developed in Austria, the CLT panels are constructed by first laminating layers of spruce at right angles, then hydraulically pressing them. The strength created is capable of withstanding the same pressure as prefabricated concrete.

In the case of Forte, the timber flooring (145mm) and walls (128mm) is simply bolted to a conventional concrete ground-floor structure, and then stacked as a platform on top of each other and screwed together for fast construction times. Although the timber will be clad externally in Alubond and plasterboard inside, a feature timber wall will be retained in each apartment.

When completed, the 32m building will have 23 one and two-bedroom apartments, including two penthouses with balconies, above the retail ground floor.

The CLT timber panels, measuring up to 16.5m by 3m, were constructed in Austria and shipped over. Importantly, they were tailored for Australian conditions.

“It’s a pretty fantastic product with enormous potential,” says Daryl. “The Europeans are doing pretty exciting stuff with it and we can see some fantastic development opportunities with it – but it is still right at the early stages in its development, so we needed to make sure we did proper research and gave full considerations.

“For example, while the buildings in England look fantastic and speak for themselves, we were mindful that they don’t have to deal with lateral loads from winds and alike that we have to – so we needed to be sure that there would be no subsequent complications.

“If you consider that concrete has had more than a century of development then you would suggest that it is a long way through its journey; whereas what we used here is right at the beginning of its journey.

“Essentially, despite all the great work around Europe, we were on a whole new learning curve above what they had done.”

While very happy with how the construction is going, Daryl says he is perhaps most impressed by the precision of the CLT system.

“When you’re talking about traditional systems, there is usually a tolerance of 10 to 20mm, but with Forte we’re talking about numbers closer to 1mm. That has enabled us to use pre-constructed kitchens and bathrooms, safe in the knowledge that they will slide in perfectly and we won’t waste time trying to fit and adjust to size.”

The excitement with Forte is not simply for the building itself, but also for what it represents for the future.

“I think it’s fairly well accepted in Australian construction that there are cost efficiencies in multi-storey apartments. Up to roughly 6-storey, you can construct with masonry, pre-cast concrete or a number of other systems and achieve good economies, and equally, once you pass roughly 15 levels, you enter into formwork and other systems that achieve good returns. But there’s been this black hole when it comes to that mid-level construction where there really hasn’t been a great economical solution in the Australian construction market place.

“It’s still pretty early in the process for us, but we believe that CLT might sit very nicely in that part of that market – and that is why we entered into the Forte project with the view that we needed to learn as much about it as we could.”

When you consider that many councils are happy to approve dwellings in that 6 to 10 level construction and that research suggests that customers are also more interested in this size development, Lend Lease’s research and development in Forte definitely makes sense. The next step will be when the Australian industry starts manufacturing CLT locally – with cost advantages obvious to both the industry and the end-consumer.

We may well be witnessing the beginning of a new generation of construction in Australia – and very rapidly at that.

Contact:

Forte

www.forteliving.com.au