Wooden it be nice?

Office districts have for many decades occupied the collective imagination as realms of concrete and aluminium. Wooden buildings, on the other hand, are more associated with houses, summer homes and sometimes projects for the services segment – who here hasn’t eaten in a wooden, mountain-style inn? But now the APA Wojciechowski architectural studio is currently working on a project that could spark a new trend: a wooden office building in the town of Wiele in Poland’s northern Kashubia region.

Wood from Sylva

“We are currently working on a number of projects using cross-laminated timber (CLT) that we hope will soon see the light of day. Sylva Drewno, the Polish subsidiary of French wood construction specialist Piveteaubois, is to move into the building and is itself responsible for producing the CLT materials. At the same time, we are also working on projects that use layered sandwiched panels, and these include hybrid projects with wood and concrete,” reveals Szymon Wojciechowski, the chairman of the board of APA Wojciechowski Architekci. Sylva also produces building frameworks as well as GL24H beams and interior surfacing materials, so it seems more than fitting that it will be moving into offices in a wooden building. The above-ground levels of the building (two and a half storeys) are to be made of wood, while concrete will be used for the underground section. The entire area of the building will come to 3,042 sqm.

Cross-laminated timber comprises 1 pct glue and 99 pct wood. The laminates are created exclusively from wood certified by the Forest Stewardship Council (FSC) and Programme for the Endorsement of Forest Certification (PEFC) to guarantee that they are derived from sustainable sources and that forests are conserved. Such timber is used to create such building elements as posts, beams, supporting walls and floor panels. The biggest advantage of using such a material is its renewability and its natural sourcing. “Wood is a natural reservoir of carbon dioxide, a natural greenhouse gas. So there are obvious benefits from using it as an ecological raw material,” argues Piotr Taube, the technical director of Sylva. Szymon Wojciechowski concurs: “Layered buildings are natural insulators and can be easily brought up to the standard of a passive building. In addition to that, the problem of thermal bridges is resolved when you cover the front of a building with a glass and aluminium façade, which also emphasises the beauty of the wood,” explains the architect. Aesthetic criteria are indeed important, especially when well-being is taken into account – and this is an issue that is being taken more seriously in the design of office buildings. Moreover, due to the climate crisis and the growing sense of responsibility for its consequences, the environment (the first letter of ESG) is becoming a pressing issue for both investors and architects.

Cheaper, quicker and prettier?

Austrian family firm KLH Massivholz played a pioneering role in the development of CLT. back in 1996, in collaboration with the University of Graz, it was the first to manufacture examples of these materials, and by the end of the century it had opened its first factory. Although in Poland there is still a lack of companies engaged in CLT production, acquiring such materials from other countries is in fact not too costly or damaging for the environment. “Currently, there are several producers that make building materials from cross-laminated timber. So the cost of importing it to Poland is not high and its transportation from distant locations reduces greenhouse gas emissions, which is extremely important. Undoubtedly, the structure itself is more costly than traditional constructions – we estimate that CLT buildings are around 6–8 pct more expensive to construct, but this cost can be significantly reduced through speedy construction, savings made on the foundation work as a result of the lightweight structure, and, above all, by the fact that exposed CLT constructions do not need to be finished, plastered or covered with tiling, nor do the ceilings have to be suspended,” points out Szymon Wojciechowski. Moreover, the waste generated on the building site can easily be recycled into new construction elements or possibly turned into wooden pellets.

A burning problem

When it comes to building with timber, it’s impossible not to consider the increased fire risk, and Polish regulations are much stricter on this issue than in the West. “Research confirms that CLT structural elements possess a very high fire resistance, but they also do not meet the current Polish fire prevention criteria. Therefore, if we want to use exposed wood, in practice this will mean that office buildings constructed using CLT in Poland can be no higher than 12m. In order to erect taller buildings under the present Polish regulations, the timbers have to be covered with cladding or coatings, and in the case of sandwich materials such cladding is used. The fire safety issue then disappears, but so does the exposed wood,” admits Szymon Wojciechowski. Piotr Taube of Sylva is also pessimistic. “Abroad, tall public buildings are constructed without any problem. In Poland, there’s a lot of resistance to them, especially due to the fire regulations. Without a change in the attitude of the fire safety authorities, I can’t see any chance of building with wood on a larger scale,” he says. However, the hope remains that scientific research and technological progress will eventually provide compelling arguments for changing the regulations. Szymon Wojciechowski is convinced that more intimate, lower-rise office buildings as well as single-family housing estates, schools and kindergartens made of wood are set to become increasingly common in Poland – and that a greater number of such projects will embolden both investors and contractors, as well as ease the worries of legislative authorities.

A lack of expertise

As is always the case with fledgling technology, the initial lack of qualified personnel can slow down the emergence of the new sector. “There’s currently a shortage of experts in timber construction working on the market. Architects and constructors simply don’t have the required know-how for this,” Piotr Taube concludes, with a twinge of regret. Szymon Wojciechowski agrees, but he stresses that the situation is starting to change for the better, and his design studio is doing a lot to popularise timber construction while at the same time educating people: “We are trying to promote timber construction. We bring up the topic during many events, we prepare scientific publications, and we hold training courses. Nevertheless, sometimes we have to rely on the support of foreign companies,” he reveals.

Looking further afield

Inspiration for Polish architects can increasingly be found across the continent. The Mjøstårnet mixed-use project in the town of Brumunddal in Norway, which has a floor area of 10,500 sqm, has recently broken the record height for wooden buildings by reaching 85 metres. However, it is soon to be surpassed by the Rocket & Tigerli tower under construction near Zürich, which is expected to have a height of up to 100m. In Bordeaux, meanwhile, the 17-storey Hypérion building was handed over to its eventual residents in 2021.