Cross-laminated timber (CLT) has been dubbed the concrete of the future. As a highly resilient form of engineered wood made by gluing layers of solid-sawn lumber together, CLT is reshaping how we understand architecture and design today. As a material with a high degree of flexibility, CLT has to undergo great deformations to break and collapse, unlike concrete. In turn, it's a material chosen for its warmth and natural properties.
First developed in Europe in the early 1990s, CLT was only introduced into the International Building Code in 2015. The ICC announced approval of 14 code changes as part of the 2021 International Building Code (IBC) that allow mass timber structures of up to 18 stories. Included in these changes is the introduction of three new construction types—IV-A, IV-B and IV-C. In this context, heavy timber is either sawn lumber or structural glue-laminated timber and is associated with Type IV construction.
Laminated timber is the result of joining boards to form a single structural unit. With CLT, the stacking of boards in perpendicular layers allows the manufacture of plates or surfaces – or walls. It's a plywood made of boards that can reach very large dimensions. The surge in mass timber and prefabricated wood construction, and recent changes in building codes to allow for taller wood buildings, is expected to not only save builders money, but also contribute to new economic growth and jobs. The following designs explore the use of cross-laminated timber through a series of projects built within the last six years.
Freemen’s School Swimming Pool / Hawkins\Brown
The scheme designed by architects Hawkins\Brown provides a 25m, six lane competition pool, with changing facilities and a multi-purpose teaching and events space. The new pool uses state-0f-the-art timber construction and offsite fabrication methods to create a sustainable building that sits gently within its context. It replaces the school’s original pool building, which a fire destroyed in 2014. It also relocates it from the west to the east side of the campus, next to the existing sports facilities.
Bellevue First Congregational Church / atelierjones
The challenge was to convert a typical multi-tenant office space into a space capable of creating awe. To do this, the architects had to bring life to the existing beige box by breaking it open and allowing the diffuse Northwest light filter in. Historically, light has played a significant role in marking a transcendent space, and this design captures the richness of indirect, cast light reflected off natural surfaces. For the new Bellevue First Congregational Church, the new soaring sanctuary is filled with this indirect light, which subtly changes throughout the day and seasons.
The Financial Park Offices / Helen & Hard + SAAHA
Bjergsted Financial Park is the new head office for SR-Bank in the centre of Stavanger. The bank’s unique position in the area will be strengthened through its new location in a central financial park and cultural arena. To make a large-scale bank in timber challenges the notion of a strong, robust bank, while breaking ground for the use of structural timber. The main structure of the 13 200m2 over ground is made of timber up to seven floors.
Community Center / NORD Architects
A small community center built in CLT wood renews the local cityscape and invites people to cultural activities. The new parish centre in a suburb to Copenhagen, is a modern gesture of sustainability – a gentle mark in wood that brings people together. The Parish Centre adds a new welcoming gathering space to Brønshøj and creates a new connection between the city square and the church that was blocked before. This is a modern church and parish center, that aims to open up towards the community in a bright, honest and welcoming atmosphere.
CLT House / FMD Architects
CLT House is a bridge between architectural thinking and sustainable construction methods. The project encompasses a reconfiguration of the existing building as the base with a new upper floor addition which spans the established gardens on the site and replans the home with a new central core for this multigenerational family home. The rhythmic quality of the sawtooth roof to the new bridge structure is both lyrical and rational.
