In the south of Stockholm, they’re building a city out of wood, one that will eventually have some 7,000 office spaces, restaurants, shops, and 2,000 homes. We just had the delivery of all the timber framing for the next level. And at the end of next week, we will have another floor. The first part of the development will be completed next year, in what is the largest urban mass timber project in the world. Mass timber is essentially wood held together in layers by glue, nails, or dowels. So, this will be one apartment with a few rooms that we're standing in. Now we're at the ground floor, so we have the concrete flooring, but you can see we've got wood all around us. At this project’s heart is a glued and layered wood called cross-laminated timber, a material similar in strength to concrete and steel. And we can see quite well here that we've got one,

two, three, four, five layers of cross laminate. Exactly, and that's what gives the strength for the building. There were some real technological breakthroughs towards the end of the 20th century, really good glues. We can now cut these large pieces of timber very accurately. And so your timber building becomes a giant piece of flatpack furniture. And what that gives you is real speed of construction. Labour savings. Cost savings. And suddenly timber can compete with other construction materials. Using wood is generally considered more sustainable than steel and concrete. In the north of Stockholm, the Cederhusen development was completed in 2022. It houses 245 apartments in four blocks, climbing 13 floors high and was built using entirely locally sourced wood. The modular structure gives the buildings another sustainable quality. This kind of building system that we can take apart and reuse when the building is at the end of its life. It’s not just Sweden where mass

timber’s popularity is rising. Helen. Hi. Welcome to Fora. Hello. Come and have a look. We have used about 37 per cent less carbon than we would have otherwise used through the construction of a concrete or a steel frame building. Finished in 2022, like Cederhusen, the six-storey Black & White Building in Shoreditch, London, is designed to have more than one life. We know at some point it will need to be reused. So, we have the ability to unbolt these bits of timber and then reuse them again. Although reuse may be fine in theory, it could be more difficult in practice. If we're going to dismantle a building and try and reuse the bits, that assumes that somebody will find a use for bits of that particular size. Another advantage of mass wood is its speed of construction. The softwood timber industry claims mass timber can beat concrete project times.

by 25 percent, and the six-storey Paradise development in central London has certainly risen quickly from its concrete foundation. The main timber structure went up in 18 weeks and was for the most part about 12 people working on site. So very few people, a very fast build. As timber becomes more popular, it’s also getting taller. The Ascent building in Milwaukee is the world’s highest timber tower, with 19 residential levels supported by a six-storey concrete base. Most of the elements are fairly similar where you’re doing a medium-sized building or a very tall building. This is going to be a very fast-evolving industry. But one recurring concern, especially for high-rise timber structures, is the risk of fire. To use timber in taller structures, there is still a lot of research underway and that's because it is a combustible material. Once you have the building occupied, that means you have all your safety devices already active,

It’s very unlikely to have a big fire. What you see behind us here are very large beams. Part of the reason for that is to allow for a charring effect in the event of fire, to always keep a core component that has the redundancy within the structure. Constructing in timber raises another important issue: cost. So, building with wood is more expensive if you only look at the material cost. But we also have the time factor. By reducing the time to build a new area, we will get rental income faster. It still only makes up a fraction of construction, but global demand for mass timber materials is projected to almost double over the next five years. That may raise concerns about whether the increasing amounts of wood required can be supplied sustainably, and whether the industry itself might be growing a little too quickly. We're embracing timber incredibly fast, not giving ourselves time to learn how to use the material sensibly and safely and efficiently.

But with each new project, it can be assumed that knowledge should increase, and as it does, it’s likely that mass timber’s unique allure as a building material will only grow.

Mass timber: the future of construction? | FT Rethink

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