Meeting the offsite challenge

ADF looks at how one firm is embracing the supply chain challenge of timber housebuilding as the industry transitions to modular offsite construction.

The construction industry is undergoing a major transition, with construction moving from building sites to offsite manufacturing. Industrially standardised products increase the quality and efficiency of construction. The turnaround time on building sites is shortened and the amount of errors reduced, and there is hardly any wastage of materials.

The potential of wood in this process is undeniable and today, offsite timber construction has major aspirations. Prefabricated wood elements enable efficient and environmentally sound without reducing quality. Studies on benefits of such a lean approach are compelling. In a 2011 study of companies that have applied lean construction methods (McGraw Hill Construction, ‘Prefabrication and Modularization – Increasing Productivity in the Construction Industry’), 84 per cent reported higher quality in construction and 80 per cent experienced greater customer satisfaction.

The report also highlighted that almost 70 per cent of projects that used prefabricated elements had shorter schedules and 65 per cent had reduced construction cost. Timber prefab construction also reduces other inconveniences such as the constant unloading of building materials, as well as the amount of on-site waste and the need to transport it.

Innovation in the housebuilding sector is much needed to achieve the Government target of 300,000 homes a year required in the UK, and offsite timber construction could be central to this. One firm which is championing timber’s contribution is Metsä Wood, whose Kerto LVL (Laminated Veneer Lumber), is used to help homes constructed offsite to be turned around in a matter of weeks. Modern engineered wood products can be used for a variety of housing projects ranging from terraced and detached homes through to apartment blocks several stories high.

The company has been making substantial efforts to find permanent partners for industrial wood construction, with the aim being to develop a project delivery network based around Kerto LVL products.

“We are aiming to build a wood-based ecosystem in Europe – a network of specialists, each of whom focuses on their core business,” says Juha Kasslin, vice president, central Europe and sales development.

He adds: “Metsä Wood’s core business will be industrial-scale LVL manufacturing, and our partner network will carry out a lot of product development based on our products. This arrangement will benefit the growth of the entire ecosystem. Cooperation is an important step in expanding the wood construction sector – including urban construction, where the greatest potential is”.

Metsä Wood has long-term supply and cooperation agreements with LVL element builders, such as Finnish operators Lapwall and Sisco. Metsä Wood supplies fixed- length Kerto LVL products from which its partners manufacture roof, floor and wall elements, as well as complete modules.

Sisco’s rapid growth is “proof that Kerto LVL can be used for practically all construction purposes,” says the firm. It points to the increasing sales in prefabricated bathroom and kitchen modules and apartment modules as indications that wooden apartment buildings are the shape of things to come. This is shown by Sisco’s ambitious goal to increase the share of tall wooden buildings in Finland from 3-4 percent to 10 percent within the next five years.

“A suitable base for each building project can be assembled from modules, and the architect can then create an impressive entity by adding attractive elements, colours, balconies, cornices, and so on,” says Lauri Halminen, CEO at Sisco. “A structural design approach enables reasonably-priced production, and industrial manufacturing ensures that the projects are carried out efficiently.”

Sisco’s counterpart Lapwall also believes in the logic and assembly chain approach that has been adopted from the automobile industry: in industrial wood construction, the work steps are clustered together and prepared in advance. All that remains to be done on the building site is to connect the parts.

“If each building is a prototype, then things become impossible,” says Jarmo Pekkarinen, CEO at Lapwall. “Our product development is based on the concept of having a range of models, with each building being assembled from prefabricated parts. This allows optimal cost, quality and speed. Thanks to this approach, we can promise developers and investors that a building project can be completed in as little as three weeks.”

Europe offers “plentiful partnership opportunities for element construction”, Metsä Wood says. In France, Germany and Belgium, for example, Kerto LVL Ripa floor and roof elements are prepared by partner companies.

Here in the UK, however, according to the company, we seem to be slow on the uptake, however it adds that the “tide is slowly turning with a greater need to provide affordable, adaptable and ecological homes”.

Despite signs of progress, Metsä Wood concludes that “more needs to be done to help housebuilders, developers and planners better realise the potential that modern wood products can offer”. This is one reason it recently launched
its Open Source Wood project (www.opensourcewood.com), where architects, designers and engineers are invited to join forces to innovate and share information relating to construction based on wood elements.

The firm hopes that such initiatives will help to highlight some of the innovative projects taking place across the globe and, through collaboration, bring timber construction methods to the forefront of new housebuilding in the UK.