The Timber Age

lisbjerg bakke housingTimber has historically been used widely in cities, and has certainly been the most familiar construction material throughout the world, used for every purpose, since timber is versatile, light weight, low cost and readily available everywhere.
The love story with concrete and steel has only lasted for a shorter period of human history, coinciding with the industrial revolution, and based on production of energy from oil and coal, enabling large scale prefabrication and transportation.

Construction Timber has, until recently, been regarded a material of the distant past - a low cost option or perhaps a 'romantic' material, but not a material of the future, to be used in urban settlements or large scale structures.

The Timber Age
This view is changing. A quiet revolution has taken place inside the building industry since the turn of the century. Gradual development of traditional timber products and invention of new timber products used for general building purposes, combined with government changes to building codes, have made a big impact and has shown that timber, again, can be used for mostly anything in modern construction - including high rise construction.
New timber products are gaining teritory in areas formerly held exclusively by concrete and steel. Most notably the invention of mass timber products such as CLT (cross laminated timber) which can be used almost interchangeably with concrete (in regard to loadbearing potential), and brettstabel (raftered decks) used for large span floor slabs, prefab facade elements and prefab box modules.
But why use timber, when timber notoriosly has problems with fire proofing, sound insulation and potential rot, compared to concrete and steel? Timber buildings needs to be constructed with great care and precariousness, to avoid these issues. The risk seems greater.
The short answer: each type of construction has it's own unique set of challenges and rewards.
Large scale timber construction is just finding it's feet, and will soon establish standardized answers to the questions that arise.
But large scale timber construction has not only proven very possible, theres is much to suggest that it is also very sensible.

The concerns with timber construction: fire, sound and rot
Solid timber will burn slowly and predictably, and is very hard to ignite. Steel on the other hand, performs unpredictably in case of fire. The technology of preventing fire has in later years expanded to scientific and thorough field of knowledge, with a wide array of fire preventing options (sprinkler systems, fire detecting and alerting systems, sealing techniques, fire containment techniques etc), effectively reducing the sensitivity the issue, even for large scale structures.
Building codes are, however, lacking behind technology in many countries, and needs to be revised to better suit large scale timber construction. In many countries designers are faced with the insurmatable task of scientifically prove fire safety above three or four stories, limiting the possibility of using timber for large scale construction.
Sound insulation in lightweight buildings is a contradictory issue, since heavy weight in itself provides sound insulation. It is technically possible but hard to achieve equal sound insulation in lightweight buildings - resulting in a thick and multilayered decking construction. The question is, if lightweight building structures should live up to the exact same sound properties as heavy buildings, since modern timber buildings already performs much better than, for example, older buildings - which most people occupy - and if the 'noise-free' standards set by heavy construction, should also set the regulatory standard of building codes, limiting a choice between different, but almost equal performing building systems - which basically offers different sets of sensory qualities.
And since noise problems derive in equal amount from local context -such as traffic - and to a lesser extent from direct neighbors.
The primary concern for timber construction should be how to avoid moisture problems in construction (in wet climate) during erection and building operation. Thus avoiding rot and eventual technical failure.
This requires a different kind of care than other construction methods, and requires unique and specific design strategies, as well as careful execution.

The qualities of timber
Timber is considerably more ressource and waste efficient and requires very little energy input in manufacturing and construction, compared to concrete and steel. It is made with energy from the sun, and utilises rest products from manufacturing process for energy production.
Co2 emissions from the softwood timber industry are close to neutral (coming from managed forests), whereas the steel and concrete industry accounts for 14% of the global carbon dioxide emissions (5% from concrete and 9% from steel).
Waste production from timber is neglectable, since timber can be disassembled, reused, burned for energy, or biodegraded in nature, without any waste. Wood is the original 'cradle-to-cradle'-material.
Wood is even more suited to prefabrication than concrete and steel, since it is abundant and renewable, low cost, lightweight, less toxic and easier to transport and manipulate in an assembly-line production.
The main benefit to the end-user however, is the unique sensory experiences provided by wood: it is is soft to the skin, has an appealing smell (to most people), a warm look and acoustics, and a capacity to regulate air moisture; providing a more healthy interior environment than found in plastic-painted or 'hard surface spaces' - like the difference between wearing a woolen sweater or a raincoat.

The challenge of timber design
The big challenge of timber design is how do we translate the sensory qualities of wood, of the smaller scale wooden building into a large scale design.
Without this approach, large scale timber construction can not obtain it's full potential.
The language of wooden construction is tectonic, flowing from the unique properties and challenges of the material itself.