Strength verification of MDF products and fitness for purpose in structural application: Assessment of the structural behaviours and fitness for purpose of MDF stair solutions
The aim of this project was to demonstrate that MDF products are safe for structural applications, in protected environments, in particular stairs. Thus, providing benefits to industry by validating information on the mechanical properties of MDF material, and the fitness of MDF for structural applications. Informing both the wider timber construction industry and also end-users to assist in improving the uptake of MDF material in structural applications.
The research comprises i) a thorough in-grade testing programme of MDF products and ii) a series a full-scale testing of several types of stair constructions.
The project addressed the characterisation of MDF materials by completing investigations in compliance with AS/NZS 1859.2:2004 and with AS/NZS 4063.1:2010 and AS/NZS 4063.2:2010 for the in-grade testing of stringers. These investigations verified that MDF is suitable for structural applications. However, noted that the availability of declared material properties is inadequate (Section 7 in AS/NZS 1859.2:2004), i.e. the published design values are limited to bending strength (MOR) alone or together with the stiffness (MOE), and is recommended to be completed with tension, compression and shear strengths.
Additionally, the report recommends improved identification of MDF products to meet the industry standard of timber based structural products. Proposing a labelling solution indicating the supplier, material class (as per AS/NZS 1859.2:2004), moisture resistance capability should be implemented and printed on the panels with frequency that ensure the labelling of off-cuts.
The findings of the project investigations inform the design guidelines outlined in this report.