Leers Weinzapfel Associates: On Collaboration, Sustainable Buildings, and Timber Structures

Leers Weinzapfel Associates is a Boston-based, award-winning practice specializing in architecture, urban design and infrastructure projects. They’ve recently worked on a tri-faculty building with an innovative timber structure for the University of Massachusetts, Amherst. We caught up with Tom Chung, Principal, to learn more about how they went about designing a building for designers, and how effective collaboration helped the project team arrive at a compelling and sustainable design.

"We use SketchUp because it is nimble and easy to use and it allows us to develop our designs quickly. We start in SketchUp and stay there throughout the design process."

You had an interesting brief with this project: Designing an Integrated Design Building for three design departments. Tell us more about this project.

Our job was to design a new home for three departments related to the design of the built environment, currently spread across the University of Massachusetts Amherst campus: the departments of Architecture, Landscape Architecture & Regional Planning, and Building Construction Technology. The purpose was to bring these departments together so that they could have synergies, collaborate, and advance their disciplines.

The building needed to be smart and sustainable, and push the boundaries of spatial, construction and landscape design... all on a tight budget as the project was state-funded.

What were some of the interesting design problems you had to address with this project?

In addition to the programmatic concerns, we wanted to respond to the existing street contexts, and capture key views across the campus. Our site stretches between two streets with very different characters; one is faced with the larger sized buildings of the campus and the other with smaller structures that form the historic part of the campus. Using SketchUp, we tested several site locations, forms, and design approaches. We arrived at a massing that responds to both street conditions with an articulated courtyard nestled in between. Our Landscape Architect, Stephen Stimson Associates, helped us arrive at a well-resolved courtyard design as well as a sustainable landscape design for the entire site.

The two story commons has become a focal point for the project because it creates a communal space for the inhabitants and visitors of the building, responds to the landscape garden on the third floor and opens up on the ground floor to welcome the rest of the campus.

This “commons” space is animated by a dynamic three-dimensional truss made up of Glulam beams and metal tension rods. Structurally, it has to support the roof garden, which has up to eighteen inches of soil and dense planting. This starts to test the boundaries of timber structures, but what better place to do that than a school designed for design?

 

Creating the commons roof structure you describe predominantly out of timber sounds pretty ambitious. Why did you choose timber over concrete or steel?

As a practice, we’re always curious about new materials and new ways of building. Alexander Schreyer, chair of Building and Construction Technology, was the main proponent of the timber structure on the client-side. It’s his area of expertise and a key research area for his department. Without that interest on Alex’s part, we might not have had the opportunity to investigate a timber structure. We enlisted the help of specialist timber structure engineers, Equilibrium Consulting, and what we’ve arrived at is the first mass timber structure of its size and scale in the United States! Pretty much all of the structure is mass timber: the structural frame is made up of glulam beams and columns and the floor deck is made up of an innovative combination of Cross-Laminated Timber (CLT) & concrete. This composite floor elegantly combines the material properties of wood and concrete to create thinner long spans that are durable, serviceable and great for vibration and acoustic control.

How did SketchUp help your design process?

Our office uses SketchUp as a design tool from the beginning of pretty much every project. We can model things easily because it’s nimble and agile. We test different massings and concepts. Depending on the location, we get a Google 3D map and plug-in our design to better understand the contextual fit. We also do early-stage animations walking through our SketchUp model to show our client what it feels like as you come close to the building and as you enter it. The walk-through feature also helps us to capture and demonstrate the quality of the major spaces.

When the client asks for design changes late in the design development stage, we will test and iterate in SketchUp before transferring it to the construction documents created in Revit. We also do focused studies of specific aspects of our design within SketchUp before consolidating it into the final drawings. The sketchy-edge style is really useful when the concept is still being refined but further along in the design process, we use SketchUp rendering extensions (such as V-Ray) to create more photorealistic images (with some post-processing in Photoshop).

How did the project address the issue of sustainability?

Selecting a timber structure meant we were using a sustainably harvested renewable material with very low embodied energy and carbon. The prefabricated nature of the timber structure also reduces on-site labor-intensive processes and will help accelerate the build process. If other clients and practitioners across the world choose to design more mass timber structures instead of concrete or steel, the industry could have a big impact on global carbon emissions.

Beyond the material specification, our limited budget meant that we could not rely on expensive bolt-on renewable strategies at the end of the design process. We like to consider the building’s performance from the very start to reduce the energy it consumes. We ruled out a LEED Platinum rating and renewable energy sources as they were beyond our budget, but we linked into the campus’ existing chiller system which is relatively efficient. We also planned spaces so that mechanical heating and cooling services could be sized and distributed efficiently.

By collaborating closely with all the project specialists, we were able to make a lot of smart decisions and we’re expecting a LEED Gold rating on completion.

Collaboration seems to be a big theme that runs through the project -- from interpreting the brief to the design process and post-completion.

Collaboration is very important to our practice and it was certainly crucial for this project’s success. There was very close collaboration between ourselves and the client, represented by the three different UMass department heads. We put a lot of thought into the spatial planning of the building to ensure that chance encounters between students and faculty across departments were maximized. We hope that the design will create multiple opportunities to interact, cross-pollinate ideas, and foster multidisciplinary collaboration.