04 - Basement and Openings

Obviously basements and lower ground floors are more likely to suffer from flood damage. In some cases, a significant amount of critical plant, services and equipment is located. It is therefore the starting point when considering adequate flood prevention and protection.


  • Unprotected basements where high values or critical equipment / installations are located.
  • Unprotected ground floor of buildings where high values or critical equipment / installations are located.
  • Buildings in poor condition.
  • Absence of a flood emergency and contingency plan in case mobile protection is needed.
  • Absence or inadequate design of basement and ground floor drainage.


  • No basement or the basement area has adequate flood protection.
  • Little or no crucial equipment in basement or in exposed areas of ground floor level.
  • Buildings in generally good condition.
  • A good flood emergency and contingency plan is addressing all protection steps for basements and openings that need protection from flood waters.
  • Drainage is designed and maintained in order to cope with extreme storm and rain events to avoid losses in basements and through ground floor openings from occurring.

Risk improvement ideas

  • Examples of (mobile) protection features for basement and ground floor areas at risk from flooding may include: backflow prevention valves, gates and pumps, bulkheads, locating key control and electrical systems above expected water levels, raised or protected stock and machinery, tank anchors, etc.
  • More resilient building materials and good general condition and maintenance of building elements will render it more resilient towards water ingress. Consider tightening the fittings and checking the seal of doors and windows.
  • New buildings should be designed with flood prevention or protection in mind. Options include:
    • Wet protection: Basement and openings are water resilient and equipment is protected or located above the designed water level.
    • Dry protection: water will NOT ingress into the basement, because the building is water tight. Although the premises flood, no water will get into the building due to sealing. This protection measure is ideal in areas with low flood levels. Alternatively, the building is shielded from water due to defenses and barriers or artificially raised above water level (stilts, walls, hills).
  • If the building is constructed of materials containing asbestos, has an asbestos survey been completed? While asbestos may be well contained during normal conditions, a flood could allow the asbestos to be damaged, releasing asbestos fibers. Not only would the building material require expensive replacement, but the released fibers could cause contamination of standing flood water and surroundings.


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