An innovative drying method for on-site and precast walls – Efficiency in accelerating the drying of reduced-scale earth-lime-hemp composites

Abstract

The drying of construction materials is a challenge regarding structure’s durability and costly construction delays. Long drying periods induce high-moisture content that leads to fungal growth risks. This study presents the development of an innovative forced convection drying method, inspired by unglazed transpired solar wall system and repurposed here for its drying potential at the wall scale. This method employs a metal perforated panel placed at a short distance from the material to dry. This creates an air cavity between them where forced convection is applied with ambient air penetrating through the perforated panel. The moistened air is evacuated thanks to an air circuit composed of a fan and an extraction duct. Two panel configurations with round and cross-shaped perforations are investigated and compared to a natural convection reference. The efficiency of the method is evaluated on Earth-Lime-Hemp composites. With forced convection method, the evaporation front moves moisture towards the near wall forced convection surface and leads to more efficient moisture removal. The results demonstrate a 50 % reduction in drying time using forced convection drying compared to natural convection drying in an open area. Both panel configurations show similar efficiency. The proposed drying method meets the challenges above-mentioned and is applicable for both prefabricated elements and on-site construction. Additionally, it can be effective for the restoration after water damage, enhancing overall construction resilience.