Introduction

The following information is intended to introduce the key elements of Part C – Site Preparation and Resistance to Contaminants and Moisture. Wherever possible the relevant document contents or sections are included with each set of regulations.

Use the link below for the full building regulations document.

• Note: All information is current as of January 2006, as is subject to change.

Resistance to contaminants

The ground to be covered by the building shall be reasonably free from any material that might damage the building or affect its stability, including vegetable matter, topsoil and pre-existing
foundations.
C1. (1) Preparation of the site and resistance to contaminants

Reasonable precautions shall be taken to avoid danger to health and safety caused by contaminants on or in the ground covered, or to be covered by the building and any land associated with the building.
C1. (2) Preparation of the site and resistance to contaminants

Adequate sub-soil drainage shall be provided if it is needed to avoid;
(a) the passage of ground moisture to the interior of the building;
(b) damage to the building, including damage through the transport of water-borne contaminants to the foundations of the building.
C1. (3) Preparation of the site and resistance to contaminants

For the purpose of this requirement, “contaminant” means any substance which is or may become harmful to persons or buildings including substances, which are corrosive, explosive, flammable,
radioactive or toxic.
C1. (4) Preparation of the site and resistance to contaminants

Section 1: Clearance or treatment of unsuitable material
Section 2: Resistance to contaminants
Section 3: Sub-soil drainage

Resistance to moisture

The floors, walls and roof of the building shall adequately protect the building and people who use the building from harmful effects caused by:
(a) ground moisture
(b) precipitation and wind-driven spray
(c) interstitial and surface condensation
Part C2. (1) Resistance to Moisture

Section 4: Floors
Section 5: Walls
Section 6: Roofs

Further information and useful links

• Making structural changes to your property
• Full guide to the building regulations
• Successfully damp proofing your home

• Find a Builder near you
• Find an Architect near you
• Find an Chartered Surveyor near you

• Building Regulations an explanatory booklet (odpm.gov.uk)
• Party Wall Guidance (rics.org)
• Impact of the Party Wall Act 1996 (odpm.gov.uk)