"Holz-On-Top" - Urban densification with modular wood constructions


Project duration: 09/2022 - 08/2024

The "HOT" project aims to investigate and demonstrate the suitability and performance of wood as a building material for rooftop extension and loft conversion through appropriate concepts. The developed construction variants should be able to respond to the different roof typologies of the existing buildings in technical and economic terms. In combination with wood and other sustainable building materials, the project aims to enable not only energy-saving, functional, and cost-effective use of living space but also to contribute to CO2 sequestration.

The following areas are considered relevant:

1. Inventory and analysis

  • Research of scientific works on the condition assessment of historical roof structures
  • Presentation of knowledge on the restoration of valuable roof structures in a guidebook
  • Inventory analysis and determination of the boundary conditions for modular densification

2. Static-constructive development of modular wood construction methods

  • Concept development for densification of the roof space with modular wood construction
  • Static-constructive processing (including key details) taking into account logistics and assembly influences
  • Analysis and concept development of connection technology ("plug-and-play" systems)
  • Static-constructive processing of key details
  • Parameter study and development of a design aid for practical application
  • Development of connection variants to the existing building

3. Building physics and building services aspects

  • Thermal and moisture-related proof of the construction elements and the overall structure (stationary and non-stationary calculations)
  • Assessment of summer overheating using thermal building simulation
  • Building services solutions for the newly created living space, taking into account the boundary conditions of the existing building
  • Creation of a modular system or cataloging of necessary building service components

4. Knowledge transfer

  • Development of guidebooks and standardized constructions
  • Conducting workshops and seminars


At the end of the project, a catalog/guidebook will be available summarizing the above-mentioned topics and their corresponding solution proposals. This will serve as a reference work for architects, planners, and engineers, the wood construction industry and wood construction companies, property developers, building owners, property managers, and authorities.

Österreichische Förderungsgesellschaft mbH (FFG)

Dieses Projekt wird aus Mitteln des Waldfonds, einer Initiative des Bundesministeriums für Land- und Forstwirtschaft, Regionen und Wasserwirtschaft gefördert und im Rahmen des Programms Think.Wood der Österreichischen Holzinitiative durchgeführt.

This project is supported by free PRO licenses from HTflux Engineering GmbH.

Förderprogramm THINK.WOOD

THINK.WOOD.Innovation - Projektart Collective Research

"THINK.WOOD" ist das Motto der Österreichischen Holzinitiative, welche vom Bundesministerium für Land- und Forstwirtschaft, Regionen und Wasserwirtschaft im Rahmen des Österreichischen Waldfonds umgesetzt wird. Das Motto soll dazu anleiten, bei der Lösung ökologischer, gesellschaftlicher und wirtschaftlicher Herausforderungen unserer Zeit immer auch an die nachwachsende und nachhaltig verfügbare Ressource Holz zu denken. Es ist ein vielseitig einsetzbarer Rohstoff von unschätzbarem Wert. Mit der Österreichischen Holzinitiative soll die Bedeutung von Holz für den Klimaschutz aufgezeigt sowie das enorme und nachhaltige Innovationspotenzial seiner Verwendung freigelegt werden.