There was a time when many of our buildings were made of wood. Stone was an expensive building material to use but as more and more people became packed into smaller spaces it became inevitable that cities had to grow upwards. Iron and steel made that easier as stone-based materials like concrete were not expected to be strong enough to carry the weight. That has allowed our buildings to soar high into the sky and the tallest have become known as skyscrapers. It is possible that the days of iron, steel and concrete being the only materials used to build the majectic structures are numbered. Timber could be set to join their ranks and soar high into the sky.
This is somewhat of a radical concept but then there was a time when other materials were considered to be unfeasible. When a concrete skyscraper was constructed in 1903 in Cincinnati, Ohio it was believed that it would crack under its own weight. One reporter even remained awake through the night after the building was opened just so he would have the scoop when the building crumbled. The Ingalls Building is still standing to this day much to many prognosticators chagrin.
Much like with concrete wood has never been considered a suitable building material for high-rise buildings. There have been legitimate questions regarding issues like its strength. How easily would they burn down? Would they be susceptible to rot and if they were how easy would it be to repair any damage?
Wood does offer some benefits though. The weight of a wooden skyscraper is substantially lower than that of a concrete or steel building. Concrete takes time to dry, as much as several weeks per floor. Wood can be pre-manufactured to be fitted into place making construction much quicker and efficient. It will also require less vehicular traffic to deliver material thereby cutting down on emissions. Wood also would remove carbon dioxide from the environment potentially making any timber building an enviro-hero.
Timber buildings are common. If cared for they can stand for hundreds of years even if no nails or modern materials were used in their construction. The Hōryū-ji Temple in Japan is believed to be over 1400 years old and like many timber buildings has survived natural disasters that have felled buildings using modern materials.
Even wooden skyscrapers are not quite new or theoretical. The 7-story T3 high-rise in Minneapolis is made of pine and is the tallest wooden building in the US. The HoHo tower in Vienna is under construction using spruce. In Stockholm the 40-story Trätoppen (Treetop) has been proposed. The tallest currently in the world is the 18-story Brock Commons at the University of British Columbia in Vancouver.
The wood used is not ordinary wood. The contractors are not going to their local building supply store and buying off the shelf materials much less using reclaimed material. Glued laminated timber, or glulam, are small pieces of wood that are glued together like plywood that can be used for beams and columns. This material has been used successfully for over fifty years. Laminated veneer lumber, or LVL, has the same strength as concrete and uses multiple layers of lumber glued together and are used for edges and headers. Cross-laminated timber, or CLT, is made of thin layers of wood criss-crossed with a fire-resistant glue making it plywood on steroids. This is the latest in technology and it is claimed to be as strong as steel, impervious to warping and comes in huge sheets that can be used for walls, floors, or roofs. The main problem with this material is that it is hard to attach each panel to another as they will need to be heavily anchored to each other to provide sufficient strength to withstand the pressure.
These materials are even fire-resistant. A test was conducted at the Fire Research Laboratory in Virginia when a room was set on fire. The furnishings burned but when the fire reached the engineered wood the fire extinguished itself. The wood was still in excellent shape and intact, a further benefit over metal which will warp and weaken when heated. The biggest concern is actually what would happen because of wind. Concrete and steel buildings are heavy and that is beneficial for them the taller they go as this weight can reduce swaying. At 2,712 feet high at the top of the world’s tallest building, the Burj Khalifa in Dubai, the wind can reach 90 mph and a lighter wooden skyscraper may not be able to stand up to those forces. The problem with lighter buildings that would be made of wood is not keeping them upright but instead holding them down in place. The only feasible solution today is to have a concrete core which many engineers consider cheating if one wants to have a truly wooden skyscraper.
That has not stopped engineers and city planners from dreaming. An 80-story wooden skyscraper is being considered in Chicago as a part of the River Beech Project. The engineer believes that wood can be built to any height and this project is to be made using beech wood. In London a skyscraper called the Oakwood Tower of the same size has also been proposed. A 145 foot high building called Framework is under construction in Portland, Oregon and may prove the feasibility of this in the US. In Tokyo a 70-story structure called the W350 is being planned. It is to be a mix of wood and steel and not planned to be ready until 2041, or the 350th anniversary of the founding of Japan. It comes with a big price tag of nearly 600 billion yen ($5.6 billion), or twice what a conventional skyscraper would cost and it would house offices, a hotel, shops and homes. Other projects are springing up across the Pacific Northwest and all over the world. Even stadiums are being proposed to be made of timber in Europe and North America.
Has a timber building revolution arrived? No one really knows for sure but its viability is being studied. For all of these buildings reclaimed wood would make great floors for the penthouse, in the corner office or anywhere else for that matter!
