In a particularly interesting thread the other day, featuring a great podcast recommendation, a discussion popped up between @Dumpster Fire Yuppie , @calculatedrisk , and I about CLT/GluLam/"Heavy Timber" construction (and also I discovered there are people out there who like brutalist architecture, which was...unexpected.)
Low and behold, an article came out yesterday about Mjostarnet, an 18-story apartment, office, and hotel tower that became the world's tallest timber building when it opened last year.
The record-breaking feat was realized thanks to a type of engineered wood called cross-laminated timber, or CLT. Part of a larger group of materials known as mass timber, it is produced by gluing strips of laminated wood together at 90-degree angles to one another, before they're compressed into huge beams or panels under extreme pressure.
A slew of new timber high-rises is set to break ground or open in 2020. HoHo Vienna, a mixed-use development just five feet shorter than Mjostarnet, has just opened for business in Austria. And while Europe has traditionally led the charge, North America is quickly catching up.
In Vancouver -- a city already home to a 174-foot-tall wooden student residence -- the Pritzker Prize-winning architect Shigeru Ban has designed a "hybrid" condo complex comprising a steel and concrete core with a timber frame that will open this year. Meanwhile in Milwaukee, Wisconsin, work on a 238-foot wooden apartment block, Ascent, is set to begin in June.
Here in America, we have typically been height restricted when it comes to Heavy Timber, although the method has become more popular in recent years with high profile projects like Hines' T3 project in Atlanta and similar developments from the company in Minneapolis and Chicago. Still, there is hope for more relaxed regulations in the near future.
The latest update to the International Building Code (IBC), which many countries and US states use as a base model for their own regulations, will allow timber buildings to rise to 18 stories for the first time. The decision is significant given that, before 2018, when Oregon became the first US state to allow 18-story wooden buildings, nowhere in America permitted anything higher than six.
The changes will come into effect in 2021 -- though they are only advisory. Some countries, such as Norway, already have looser height restrictions in place, while other countries and US states may opt for tighter building codes than those outlined in the IBC.
In my discussions with some people involved in these types of projects, at the moment Heavy Timber is approximately 10%-12% more expensive than concrete, but are able to be built much faster, saving developers money on interest during construction and getting tenants in the building paying rent earlier than usual. Additionally, these buildings are better for the environment (assuming they are sourced from sustainable forests), which is a positive thing for the planet and also a great marketing tool.