CLT Hybrid was created to make hybrid construction a more viable building style. The design concept is based on a pre-designed base structure, allowing the building’s individual elements to be tested using various possible material types—CLT, hollow-core slabs, concrete, and wood cassettes.

This allows the building concept to be tailored to the specific wishes and needs of individual clients or property developers, all with the aim of optimizing the structure itself and building in a more resource-efficient and cost-effective manner.

DEMONSTRATION

The video clip and screenshot below show a beta version of how the concept works in practice (please note that this version does not necessarily reflect the final presentation). Here, you can adjust and test material combinations for various structural elements, such as load-bearing walls, facade walls, floor slabs, roofs, shafts, and others.

The embedded material data for the various elements provides real-time feedback on different design choices, indicating changes in construction costs (both per square meter and total cost), material composition, LCA calculations, total CO2 emissions, and much more.

Different configurations can be created and tested simultaneously, allowing the user to evaluate various building layouts and compare key data so that critical decisions can be made on as informed a basis as possible.

THE CONCEPT

The stability of the structure is ensured either through CLT or concrete element cores, with CLT used in the load-bearing walls to minimize CO2 emissions. Prefabricated wood elements and cassettes also enable rapid assembly, leading to fewer errors and a more predictable construction process. This is particularly important for wood structures, as they are more sensitive to wind and weather during the construction phase.

CLT and wood cassettes have a lower carbon footprint during production than other common materials such as steel and concrete. By combining these more environmentally friendly materials, the building’s overall carbon footprint is thus reduced. The result is a competitive concept that allows for leveraging the individual strengths of the materials and offsetting their respective weaknesses, thereby optimizing the project’s economics and LCA.

ROOF CONSTRUCTION: Wooden elements with roofing felt and solar panels. Shingles, natural slate, or profiled sheets are available for purchase.

FACADES: Wooden elements with natural slate and thermally treated wood. Facing tiles or profiled sheets are available as optional extras.

FLOOR SLAB: Hollow-core slab with wooden flooring on joists. CLT slabs and other floor types are available as optional extras.

GROUND FLOOR SLAB: Standard concrete foundation and ground floor slab.

BATHROOM CABINS: Lightweight bathroom cabins, with the option to customize tile selection and plumbing fixtures.

The configuration below shows an example of a concept building, with an overview of the material types selected for the various elements. In this concept, the hybrid construction combines CLT, concrete, and wooden cassettes, ensuring that each material is used where it is most advantageous structurally, environmentally, and economically. The result is a turnkey single-story house with a price per square meter of 17,695 Danish kroner and a sustainability profile of 6.0 kg CO₂eq/m²/year. Other configurations are possible, which will result in different prices and CO2 emissions.

WHY HYBRID CONSTRUCTION?

Hybrid construction combines structural elements made of different materials, rather than the more traditional approach, where a building is typically constructed using a single specific material as the primary element.

Different materials have different strengths and weaknesses. Concrete has high compressive strength, good fire resistance, and a long service life, but is heavy in terms of both weight and CO2 emissions. Steel has a high strength-to-weight ratio, is flexible, and is easy to prefabricate, but it is expensive and energy-intensive to manufacture and can be sensitive to environmental conditions and temperature. Wood is a renewable resource that is lightweight, easy to work with, and has good thermal and indoor climate properties, but it is a combustible material, susceptible to moisture, rot, and pests, and requires more maintenance than the other alternatives.

Individually, the various materials have a number of advantages, but also disadvantages that are difficult to overcome on their own. However, by combining different types of materials, they offset each other’s challenges, allowing each material’s strengths to be utilized to their fullest potential precisely where they yield the greatest structural and environmental benefits, the best possible economic conditions, the best user experience, and so on.

The construction of the future is therefore not about finding the best material to build with, but rather about capitalizing on the individual strengths of different material types so that we get the best of all worlds.