07 - Sensitivity of Buildings to Water

Buildings have varying degrees of sensitivity to floodwater damage depending on construction materials,  age and condition of buildings. While some buildings can withstand water ingress easily and can be cleaned up quickly, others may be heavily damaged due to water ingress or debris impact.

Consideration should be given to the type of flood expected. A river flood with high stream velocity and water-borne debris can heavily damage a brickwork building, while retained flood water can damage composite (sandwich) panel elements, gypsum board façade elements, etc.. Such retained water can also affect soil conditions and the building foundations. Equipment and interior finishes and cladding need to be considered also.

Note that only the lower areas of the building that are potentially subject to flooding require implementation of some level water protection. 

Hazards

  • Building materials with limited resistance to high or fast-flowing flood water, such as lightweight facade panels, timber, brick veneer, glass, linoleum, gypsum plaster etc.
  • Poorly maintained or deteriorating buildings.

Controls

  • Building materials with good resistance to high or fast-flowing floodwater, such as reinforced concrete walls and floors.
  • Building materials with some resistance to high floodwater such as brick walls, pre-cast tilt-up concrete panels, tiled floors, poured concrete foundations etc.
  • Foundations which have considered saturation of soil due to potential flood.
  • Purpose designed building construction materials with appropriate levels of inspection and maintenance.

Risk improvement ideas

  • When designing and building new premises, ensure the design takes into account the risk of flooding, and flood resilient materials are used in the building design where flooding is expected to occur.
  • When renovating existing premises, consider using flood resistant materials.
  • Consider not only water depth in a flood, but also the speed and type of water body. Especially in upper river regions, the water depth may be limited, but the river will carry a lot of bed load and debris such as tree trunks etc. 

Resources

Zurich Resources