Mono-material Wood Wall | Novel building envelope using subtractive manufacturing of timber profiles to improve thermal performance and airtightness of solid wood construction

As found in the paper: Interior views of Phase 2 demonstrator ©IBA Thüringen: Thomas Müller.

The paper focuses on the research and construction of a contemporary log construction by the University of Stuttgart. The precise fabrication and interlocking joinery reduces the air permeability and slits between timber elements significantly improving thermal insulation.

This research seeks to improve the energy performance of solid-timber building envelopes by introducing air chambers into construction elements to increase thermal insulation values and using all-wood joinery to reduce air permeability. This paper documents the development of a construction system that minimizes non-wood materials to reduce embodied energy and facilitate dismantling and low-impact disposal of building components. The developed system satisfies structural, thermal, and airtightness requirements with a pure wood primary construction system.

Sawing deep slits into solid timber profiles introduces air chambers which reduce thermal conduction across the building envelope. Tabulations demonstrate a potential thermal conductance reduction of over 30%, with measured conductance values confirming calculations. The slits have the added benefit of reducing internal stresses which can cause deformations that reduce energy performance over a building’s lifetime. The construction system implements all-wood joinery to minimize use of glues, binders, and metal fasteners. CNC milling gives the precision necessary to achieve airtightness values within required building norms with minimal use of weatherproofing sealants, tapes, and gaskets. Custom design-to-fabrication software generates unique interlocking component geometries which facilitate an assembly process that results in good building energy performance without specialized installation training for its construction. Results are measured through standard tabulation, physical testing of laboratory samples, and built projects, with two iterations of the system being implemented in full-scale demonstrator buildings.

Abstract (Bucklin, Menges, Amtsberg, et al., 2022)

As found in the paper: Completed Phase 2 modules awaiting transport. ©Ackermann GmbH: Jens Kestler.

Find paper here: https://www.sciencedirect.com/science/article/pii/S0378778821008811?dgcid=author#!

and in the next volume of Energy and Buildings, January 2022

Bucklin, O., Menges, A., Amtsberg, F., Drexler, H., Rohr, A., & Krieg, O. D. (2022). Mono-material wood wall: Novel building envelope using subtractive manufacturing of timber profiles to improve thermal performance and airtightness of solid wood construction. Energy and Buildings254, 111597.