This document is available as part of the Construction Information Service. The Construction Information Service brings together a comprehensive collection of essential technical documents from a wide range of publishers in one online package. Covering all aspects of building, engineering, design and construction, it provides its users with a single source for all their technical information needs. Contact us today to find out how to become a subscriber to this indispensable service.

Site preparation and resistance to contaminants and moisture (2004 edition incorporating 2010 and 2013 amendments) (For use in England)

Building Regulations 2010: Approved Documents C

NBS, 2013
Site preparation and resistance to contaminants and moisture (2004 edition incorporating 2010 and 2013 amendments) (For use in England)

Document Status



Core Supplement


Building Regulations 2010: Approved Documents


Provides practical guidance for complying with building regulation requirements relating to: site preparation and resistance to contaminants and moisture. It also covers clearance or treatment of unsuitable materials, sub-soil drainage and includes examples for damp proofing and ventilation.


This current reprint of Approved Document C - Site preparation and resistance to contaminants and moisture, incorporates amendments made to the 2004 edition, including the July 2013 amendments that came into force on 1 October 2013. Effective from 1st December 2004. See also: Approved Document C. Frequently asked questions (MHCLG, 2016). Main changes made by the 2013 amendments: Guidance on radon protective measures. Update references to British Standard design standards. Contaminated land guidance, including removal of Annex A and materials and workmanship. There have been no changes to Part A of Schedule 1 to the Building Regulations. Main changes made by the 2010 amendments. The 2010 amendments reflect the Building Regulations 2010 and Building (Approved Inspectors etc.) Regulations 2010, including regulation number changes as a result of re-ordering. There have been no amendments to the substantive requirements in Part C of Schedule 1 to the Building Regulations. Main changes in the 2004 edition: This edition replaced the 1992 edition (with 2000 amendments) edition with the following changes: site investigation recommended as the method for determining how much unsuitable material should be removed. Requirement C1(2) applied to material change of use as set out in Regulations 5 and 6. Remedial measures for dealing with land affected by contaminants expanded to include biological, chemical and physical treatment processes. The area of land around the building subject to measures to deal with contaminants. Guidance on protection from radon expanded to include buildings other than dwellings. Guidance included on sub-soil drainage and the risk of transportation of water-born contaminants. New guidance on condensation risk to floors, walls and roofs. Guidance provided on the use of moisture resistance boards for flooring. Updated guidance on assessing the suitability of cavity walls for filling. Former requirement F2, condensation in roofs, transferred to Part C.




Publisher History

NBS are committed to offering distinctive, innovative specification and information solutions to construction industry professionals and are proud to be leading the construction industry in its digital evolution. Their roots lie in the UK's National Building Specification and for nearly 50 years has been helping the construction industry build better and with lower risk. Their future lies in cloud-based technologies and connected data, as they fast become the information marketplace for the global construction industry.



NBS has produced specification systems and information products for construction industry professionals for more than 40 years. The National Building Specification is the recognised UK national standard and is used by over 5,000 organisations. NBS is part of RIBA Enterprises Ltd.

IHS Markit

IHS Markit is a leading global source of critical information and insight for customers in a broad range of industries. Our customer product and service solutions span four major areas of information: energy, product lifecycle management, environmental and security. By focusing on our customers first, we deliver data and expertise that enable innovative and successful decision-making. Customers range from governments and multinational companies to smaller companies and technical professionals in more than 180 countries. IHS has been in business since 1959 and employs more than 3,500 people in 35 locations around the world.

Request a quote

The Construction Information Service (CIS) gives subscribers 'the information advantage' in today's competitive market.

To request a quote, complete the form below, selecting your supplements of interest.

  • Core
  • Building
  • Construction Management
  • Mechanical and Electrical
  • Planning and Development
  • Civil and Structural

First name:
Email address: