NHBC Standards – 5 1 Substructure and ground bearing floors

Chapter  5.1 This Chapter gives guidance on meeting the Technical Requirements and recommendations for substructure, excluding foundations.  It includes substructure walls, ground bearing floors (where depth of fill is not more than 600 mm), basements and installation of services below dpc. 

Basements can be difficult to make waterproof. Although relatively small in number they can cost the NHBC considerable amounts in claims repair costs.  It is therefore necessary to pay attention to their design and construction.  Basements which are used for habitable purposes need to be dry,  but this is not so critical for uses such as underground parking.  The Standards explain what constructions are appropriate for different situations.

NHBC Standards do not cover aspects of health and safety relating to building operations and to the handling and use of certain building materials. Such matters are covered by statutory requirements.

This version of the Standards has been updated to include the Amendments to the Standards April 2004.  In general, internal tanking systems will not be acceptable in future for new-build tanked protection where this is the sole water resisting measure. (NHBC Standards Extra, Issue 29, April 2004).

Previous versions of the standards can be accessed in the Archive section (below).

Section 5.1 Contents

DESIGN

•        Design Standard

•        Statutory requirements

•        Transfer of loads

•        Ground conditions

•        Services and drainage

•        Walls below dpc

•        Ground below fill

•        Hazardous fill

•        Fill deeper than 600mm

•        Floor slab damp-proofing

•        Damp-proof course

•        Thermal insulation

•        Ground floor slab

•        Basements

•        Provision of information

MATERIALS

•        Materials standards

•        Masonry below dpc

•        Site mixed mortar

•        Proprietary mortar

•        Wall ties

•        Wall insulation

•        Fill

•        Damp-proof membrane

•        Concrete

•        Tanking materials

•        Floor insulation

•        Damp-proof course materials

SITEWORK

•        Sitework standards

•        Walls below dpc

•        Ground below fill

•        Fill supporting ground bearing slabs

•        Trench backfill

•        Blinding

•        Damp-proofing floors

•        Damp-proof course

•        Laying thermal insulation

•        Laying the slab

APPENDIX 5.1-A

•        Statutory references

APPENDIX 5.1-B

•        Materials for use as fill

APPENDIX 5.1-C

•        Basement constructions

APPENDIX 5.1-D

•        Typical details for basements

LIST OF CHAPTERS
INDEX

Archive

Chapter 5.1 (2003)

Amendments to the Standards (2003)

Source: NHBC Standards

            April 2004