"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 conversions 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 the energy-saving, functional, and cost-effective use of living space but also to contribute to CO2 reduction.

The following points are considered relevant:

1. Inventory and analysis

  • Research of scientific papers dealing with the assessment of roof structures of historical buildings
  • Creating guidelines on the restoration of valuable roof structures
  • Inventory analysis and determination of the constraints for modular densification

2. Static-constructive development of modular wood construction methods

  • Concept development for densification of roof space using modular wood construction
  • Static-constructive processing (including key details) taking into account logistics and assembly
  • 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 alternative connection techniques to the existing building

3. Building physics and installations for facilities 

  • Thermal and moisture-related assessment of construction elements and overall structure (stationary and non-stationary calculations)
  • Assessment of summer overheating using thermal building simulation
  • Planning utilities for the newly created living space, taking into account the constraints of the existing building
  • Creation of a modular system or cataloging of necessary utility components

4. Knowledge transfer

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


At the end of this project, a catalog/reference book will be available summarizing the above-mentioned topics and their corresponding solution proposals. The book will serve as a reference 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.