Tall Mass Timber

Optimizing Wood Construction: The Rise of Tall Mass Timber Buildings

Tall Mass Timber Projects

Foreword by Ian Thompson, Editor

Tall Mass Timber Construction is Gaining Popularity in the USA

Please excuse the pun, but mass timber projects in the United States are on the rise. This video, courtesy of The Build Reviews guest authors WoodWorks outlines the various reasons that have contributed to the growing interest and use of Mass Timber.In recent times, the number of tall Mass Timber projects, both constructed and in the design phase, has seen a significant increase.

While cost and aesthetics often lie at the heart of such decisions, associated factors like framing configurations, code navigation, and sustainability also play a vital role in determining when and how Mass Timber is used.

This video takes us through the experiences of three tall Mass Timber projects, giving us insights into the future of how this material can help solve housing needs. It demonstrates how Mass Timber, a sustainable and aesthetically pleasing material, can offer a unique alternative to traditional construction materials like dimensional lumber, concrete, and steel.

The video also highlights a unique project in Denver, where a rapidly growing neighbourhood has used Mass Timber to differentiate itself from the surrounding multi-family units. The video further illustrates how Mass Timber can lead to millions of dollars in savings, and how it has been instrumental in the construction of an 18-story building, which is now under construction.

The video also touches upon the challenges and victories of the code navigation process, including the successful amendment to the 2024 IBC, which allows for 100% exposure of the timber in type 4B construction up to 12 stories.

Introducing new construction techniques to countries unfamiliar with this type of construction does present challenges. However, companies equipped with the appropriate skills usually navigate these hurdles, eager to adopt these novel and advanced building systems. This often involves educating and guiding others along the way. Once through, the doors open to an entirely progressive approach to design and construction. This progression towards more efficient practices is a much-needed change in the industry.

My objective is to glean insights from tall mass timber construction and apply them to low mass timber construction. This approach aims to provide an affordable means of making high-performing building systems like mass timber accessible ‘mass’ single-family construction.

Video Transcript

In a short period of time, the number of tall Mass Timber projects in the US, both those built and those being designed, has grown rapidly. As the industry experts at the Hub of this growth, WoodWorks has seen a variety of reasons for the interest and use.

Although cost and aesthetics are often at the core of these decisions, there are many associated factors such as framing configurations, code navigation, and sustainability which all influence how and when Mass Timber is used. This video shares the experiences of three tall Mass Timber projects and points to the future of how tall Mass Timber can help solve housing needs.

Mass Timber is this wonderful material we’ve largely built out of dimensional lumber, concrete, and steel, so it was very exciting to our team to be able to actually design something in a new material. The number one thing that we were thinking about in concept for our project was product differentiation.

We’re developing in a really quickly growing neighborhood in Denver and there’s thousands of multi-family units under construction all around us by massive national builders from all over the country. And so we have a tiny little chunk of this neighborhood and we just wanted to do something different.

And so we were first struck by the aesthetic differentiation of mass Timber – just the exposed wood is a beautiful product. So first it was aesthetic differentiation, and then we started learning more about the environmental impacts of mass Timber and how it compares to traditional construction types in a high-rise, and it was just a no-brainer to go Mass Timber.

Mass Timber is also very sustainable material which it was really important for us to be highly sustainable in everything that we’re doing. But our real target was to try to provide housing, create design, build housing for the missing middle. And that is the people that are between 80 and 120% of the average medium income and most housing is not designed to be affordable by that group of people.

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By going with MPP and doing independent testing, we are able to move the column spacing from about 10×10 to 12 by 15. And so we eliminated 47 columns per floor. It was, you know, significant – every single one of these components adds up to millions of dollars of savings.

So if if we were to build a building conventionally using concrete, it would cost $100 million. We are able to go with a point load, i.e. no beams for the next three floors, and it was incredibly fast and very cost-effective. We said this is it, this is what we’re going to use, build our 18-story building which is now under construction.

We knew we were going to be building in type 4B. We had to be at 12 stories for our project in Denver to make sense. And you know, a big challenge when we started that deal was dealing with that 20% exposure limit where you can only show 20% of the ceiling. It wasn’t financially feasible, it defeated our product purpose.

And so we kind of linked up with this coalition that had already spent years and done a tremendous amount of work and research with the International Code Council to prove out Mass Timber. And they had done some new fire safety testing and had proposed a new amendment to the 2024 IBC basically saying we should be able to expose 100% of the timber in type 4B construction, which goes up to 12 stories, which is where we sat.

Luckily, we were able to get that approved for 2024. And so we took that back to Denver and our development team went to the city and proposed that we adopt this provision that’ll be happening in 2024 early. And Denver is, as I mentioned before, very encouraging and excited about Mass Timber and they voted to approve that unanimously. And so Denver became one of the first, if not the first cities in the country to allow this new provision for the 2024 IBC where you can expose 100% of the CLT up to 12 stories.

This was a type 4C project, so you think simple, everything’s exposed. And yet there’s all these different relationships and connections that need to be thought of as well. The codes despite our best efforts in that ICC Tall Timber uh building committee, we hadn’t clarified exactly what it means to have a 2-hour connection and to have uh fire joints that are protected at those at those moments and what does that mean to have you know joints that are fire protected without putting that ugly little red around the edges of those two pieces of beautiful wood coming together.

Like who wants that in their project right? So it was a really tricky balance between all of those different issues and we wanted to make sure before we went in for building permit that we had a solution that th ecity of Seattle building department would accept and I really have to acknowledge the cooperation and the good faith and the effort that the City of Seattle put in. They were really amazing I would call them design Partners on this project. There’s an incredible set of resources.

Woodworks is an amazing tool. Amazing group of people that are really dedicated and really focused on really helping move an advanced Mass Timber forward, but I would be patient and I would not try to do it halfway through the project. I would not try to introduce Mass Timber as, “Well, maybe we can do it later” kind of thing.

I would do it, make sure it’s in the beginning, make sure you have the right team. A lot of times people call me and say, “Susan, how do you do this?” Please don’t call me, but call Woodworks. You know there’s a lot of really good resources out there.

I think that with this exposure limit being increased to 100% up to 12 stories, I think that cost-wise, mass Timber really starts to compete in multi-family with concrete and heavy steel in that 8 to, well, I guess 8 plus story range. And so I really think that there’s a new opportunity for folks in cities who are able to expose 100% in type 4B to build multi-family up in that 8 to 12 story range. So I’m really hopeful that when folks are looking to build multi-family and a high-rise application, that mass Timber is one of the options that they’re looking at alongside concrete and steel.

So it’s incredibly sustainable. It is incredibly strong. It uses much less energy. It’s a wonderful product. So we look at it as being a way to build buildings faster and for a lot less money in the future. And I think as people sort of get over the beauty of the wood and they start to get into the practical nature of of this product, you’re going to see a lot more buildings that are designed and built out of this.

In 5 years, I see, you know, hundreds of eight to – I’m going to call it maybe 15 story, 12 story buildings certainly in that range, and maybe a few of the taller. I do think there will be some taller buildings. There’ll be more a sense that are going through a performance-based criteria, and I’m really excited for that. And I see a lot of buildings under 18 and under, and I can’t wait to be part of that story.

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