In the joint project “Timber in the addition of storeys - evaluation and implementation of timber in additions”, the Ruhr University Bochum and the Technical University of Braunschweig, together with other project partners, have drawn up a construction catalog with relevant structural and design requirements for additions in timber.

In addition, a generally applicable system for calculating life cycle assessments for such measures has been developed.

Resource-efficient construction with wood

With its special characteristics (low weight, high load-bearing capacity, good prefabrication options), wood offers an ideal solution for adding storeys to existing buildings, especially for redensification in urban areas. “By continuing to use existing building structures, adding storeys also makes sense in terms of conserving resources,” says Prof.'in Dr.-Ing. Annette Hafner, project coordinator and head of the Resource-Efficient Building working group at the Faculty of Civil and Environmental Engineering at RUB. The use of wood in construction not only creates living space but also has a positive effect on the climate. The carbon absorbed during growth remains in the wood products used in the building.

Based on 147 projects

The structural design and building physics requirements of 147 storey addition projects in the D-A-CH region were examined. Existing calculation systems were adapted and further developed for the life cycle assessment of additions to storeys and applied to already implemented additions. The method developed is also suitable for refurbishment and extension measures and takes into account the life cycle not only of the existing building but also of the extension measure. A detailed catalog has now been created for planners and decision-makers with various extension constructions (wall, roof, ceiling). The catalog contains basic instructions for adapting and expanding the component structures and details based on the requirements determined for thermal, sound, moisture and fire protection. In addition, the catalog presents life cycle assessment results at the material level of the developed constructions and information on the storage of biogenic carbon components within the constructions and makes them available to the public.

Free of charge and public

The timber construction catalog was integrated into the free online life cycle assessment tool eLCA of the Federal Institute for Research on Building, Urban Affairs and Spatial Development (BBSR).

The joint project was implemented in close cooperation with partners from the housing construction sector (including HolzUnion, Assmann Beraten&Planen, Nibelungen-Wohnbau-GmbH) and funded by the Agency for Renewable Resources (FNR).