Resilience measure: Wet-floodproofing technology


Wet-floodproofing can be an appropriate approach to improve the flood resilience of new and existing buildings, particularly in areas at high flood risk. Wet-floodproofing is defined as a strategy that permits water to enter a property rather than dry-proofing which prevents ingress. Hence, the principle intention of wet-proofing is to change the design and/or the material of potentially affected building constructions in order to mitigate their flood vulnerability and to minimise the extent of necessary repair works after a flood. Wet-floodproofing comprises the application of improved materials for layers of flood-prone wall, ceiling and floor constructions, which are less susceptible to flood damage.

Co-benefits and impacts

The advantage of wet floodproofing is that it is less costly than other retrofits, no additional land is required and it does not affect the appearance of the house
(Blueprintforsafety, accessed on Sept. 2016).


Wet floodproofing may only be an appropriate resilience method for certain buildings and uses. Acceptable situations include flooded areas that are used for non-residential uses including basements, sub-floor crawlspaces, parking garages, storage areas, and some commercial areas. It is also important to note that wet floodproofing does not guarantee protection from high hydrostatic pressures caused by fast-moving flood water, wave action, and any debris that is carried by those flood waters. Considerations for these types of events may require the use of flood barriers, green infrastructure, shoreline protections, levees, or flood walls to combat effects. Wet flood proofing measures should be aligned with a building’s Emergency Plan. Some components of wet floodproofing involve actions on the part of building occupants in order to be successful. If pumping of floodwaters is required, it should be noted that risk of structural damage is increased when surrounding foundation earth is saturated. Pumping may need to be done slowly for this reason. Building enclosures should be designed with drainage in made, and provisions must be made to allow water vapor to evaporate to the interior, exterior, or both, in order to avoid mold and structural rot associated with trapped water. Building mechanical systems should ideally be relocated to floors above the DFE. Any equipment that cannot be permanently located above flooding areas should be easily movable and identified as objects that require relocation when flood risk is high
(DDC Building Resilience Database, accessed on Sept. 2016).

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Last modified: Sept. 14, 2016, 6:30 a.m.