New NHBC Standards Chapter 5.4

'Waterproofing of basements and other below ground structures'.

In 2013, we launched a Basement Campaign highlighting significant issues with the design and construction of basements. Between 2005 and 2013, claims related to waterproofing below ground cost NHBC in the region of £21 million and affected around 890 homes.

A key component of the campaign is the introduction to NHBC Standards of a new Chapter 5.4 'Waterproofing of basements and other below ground structures'. The new Chapter introduces meaningful benchmarks and supporting technical guidance.

Return to NHBC Standards

Talk to us

For more information or technical support, you can give us a call or send us an email.


Where does the new Chapter apply?

The range of structures that require waterproofing goes significantly beyond what might typically be considered as basements. Below ground constructions that generally require waterproofing, and should take account of the new Chapter, include:

  • Basements
  • Semi basements
  • Below ground parking areas
  • Lift pits
  • Cellars
  • Storage or plant rooms
  • Service ducts or similar that are connected to the
  • below ground structure
  • Stepped floor slabs where the step is greater than 150mm.

Near to ground constructions that may require waterproofing include:

  • External walls where the lowest finished floor level is less than 150mm higher than the external ground level.

Watch this video for more information about the new chapter, an overview of the changes and to find out what you will need to do if you are designing or constructing basements or other below ground structures.

standards 2014

Further details on Chapter 5.4

In order to help facilitate these changes, the new Chapter will become effective only when included in the re-launch of NHBC Standards, due to be published later in 2015. However, while the Chapter will not become effective immediately, it is strongly recommended that the guidance is adopted at the earliest opportunity.

Further information and guidance is available in this special edition of Technical Extra 16