Flood resilience: reducing building drying time and indirect costs of flooding

Abstract

Flood resilience of buildings allows efficient recovery after inundation. Drying of walls is an important part of the process as moisture levels must be reduced to allow completion of refurbishment work and reoccupation. Masonry cavity walls are a widespread form of construction in the UK and can absorb a considerable mass of water in the capillary porous networks of bricks, blocks and mortar joints.

Improving the flood resilience of masonry cavity wall construction is important for adaptation in response to the climate emergency. Effective design of flood resilient construction, for new build and retrofit works, depends on an understanding of flood exposure and water transport behaviour of masonry materials. The literature review establishes current regulatory requirements for management of flood risk and building development. Materials and technologies for masonry construction are identified, with exploration of water transport properties and modelling. Methodologies are developed for experimental investigation and microstructural characterisation of masonry materials, centred on testing stub walls in a simulated flood cycle.

Hybrid silica-based additives and coatings, produced with sol-gel technologies, are considered as a modification for masonry. The investigation established that additives modified the microstructure of cementitious mortar, particularly in conjunction with non-hydraulic lime, and hence water transport behaviour of masonry walls. Coatings reduced water absorption through a combination of pore structure modification and hydrophobic action, so are more suitable for modern, cavity wall systems than traditional, breathable structures. Further development is recommended to refine mix proportions for additives and application processes for coatings.

Experimental results were consistent with a sharp-front model of wetting but differed from two-stage drying models at the initial and final stages of drying. A refined model is developed by consideration of literature from related fields. The insights provided inform recommendations for improving flood drying times by focusing on ventilation to ensure air with capacity for evaporation reaches all areas affected by flooding.

Date of Award	4 Dec 2023
Original language	English
Awarding Institution	University of Bath
Supervisor	Juliana Calabria-Holley (Supervisor), Andrew Heath (Supervisor) & Pete Walker (Supervisor)