Publishing information

This British Standard is published by BSI and came into effect on 30 November 2009. It was prepared by Technical Committee B/526, Geotechnics. A list of organizations represented on this committee can be obtained on request to its secretary.


This British Standard supersedes BS 8102:1990, which is withdrawn.

Information about this document

This British Standard was originally published in 1990, superseding the earlier CP102 (1973). This is a full revision of the standard, and introduces the following principal changes:

  • a) a number of recent developments are addressed, which are important when specifying, designing and constructing below ground structures, including:
    • 1) more deep construction in congested urban areas;
    • 2) an increase in the provision of residential basements;
    • 3) development and use of new materials for waterproofing;
  • b) a more detailed assessment is provided of the risks inherent in below ground construction and how these might best be addressed.

In addition to the introduction of these key changes, the publication of the Eurocodes and the approaching withdrawal of the corresponding British Standards make this revision timely.

It is noted that the figures used in this document are only representative of different installation methods, and should not be translated directly into practice without first checking all the parameters specific to the installation.

Use of this document

As a code of practice, this British Standard takes the form of guidance and recommendations. It should not be quoted as if it were a specification and particular care should be taken to ensure that claims of compliance are not misleading.

Any user claiming compliance with this standard is expected to be able to justify any course of action that deviates from its recommendations.

It has been assumed in the drafting of this document that the execution of its provisions is entrusted to suitably qualified and experienced people, for whose guidance it has been prepared.

Presentational conventions

The provisions in this standard are presented in roman (i.e. upright) type. Its recommendations are expressed in sentences in which the principal auxiliary verb is "should".

Commentary, explanation and general informative material is presented in smaller italic type, and does not constitute a normative element.

Contractual and legal considerations

This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.

Compliance with a British Standard cannot confer immunity from legal obligations.

1 Scope

This British Standard gives recommendations and provides guidance on methods of dealing with and preventing the entry of water from surrounding ground into a structure below ground level.

It covers the use of:

  • a) waterproofing barrier materials applied to the structure,
  • b) structurally integral watertight construction; and
  • c) drained cavity construction.

It also covers the evaluation of groundwater conditions, risk assessment and options for drainage outside the structure.

It applies to structures which extend below ground level and those on sloping sites.

This British Standard does not give recommendations concerning the use of embedded heating in structures, floors and walls or for the special requirements in connection with the design and construction of cold stores.

NOTE Structures are generally characterized as "deep" if they have more than one storey below ground level, or "shallow" if they have only a single storey below ground. This standard is applicable to both.

2 Normative references

The following referenced documents are indispensable for the application of this document. For dated references only the edition cited applies. For undated references the latest edition of the referenced document (including any amendments) applies.

BS 743:1970, Specification for materials for damp-proof courses

BS 5930, Code of practice for site investigations

BS 6100-3, Building and civil engineering - Vocabulary - Part 3: Civil engineering - General

BS 8004, Code of practice for foundations

BS 8204-1, Screeds, bases and in situ floorings - Part 1: Concrete bases and cement sand levelling screeds to receive floorings - Code of practice

BS 8747, Reinforced bitumen membranes (RBMs) for roofing - Guide to selection and specification

BS EN 1504, Products and systems for the protection and repair of concrete structures - Definitions, requirements, quality control and evaluation of conformity

BS EN 1992, Eurocode 2: Design of concrete structures

BS EN 1993, Eurocode 3: Design of steel structures

BS EN 1993-5, Eurocode 3: Design of steel structures-Part 5: Piling

BS EN 1997, Eurocode 7: Geotechnical design

BS EN 10210, Hot finished structural hollow sections of non-alloy and fine grain steels

BS EN 10219, Cold formed welded structural hollow sections of non-alloy and fine grain steels

BS EN 10248, Hot rolled sheet piling of non alloy steels

BS EN 10249, Cold formed sheet piling of non alloy steels

BS EN 12063, Execution of special geotechnical work - Sheet pile walls

BS EN 12970, Mastic asphalt for waterproofing - Definitions, requirements and test methods

3 Terms and definitions

For the purposes of this British Standard, the terms and definitions given in BS 6100-3 and the following apply.

3.1 cavity drain membrane

dimpled, flexible, high-density polymer sheet, which can be placed against the internal face of a structure after construction and is designed to intercept water penetrating the structure and direct it to a drainage system

3.2 cut-off wall

embedded retaining wall (see 3.4) designed to surround and seal-off an area, to inhibit water inflow from the surrounding area

3.3 damp area

area which, when touched, might leave a light film of moisture on the hand but no droplets of water (i.e. beading)

NOTE This definition has been taken from the ICE publication. Specification for piling and embedded retaining walls [1].

3.4 embedded retaining wall

wall used to support the sides of an excavation, installed in advance and penetrating below the lowest level of the below ground construction

NOTE Within this standard the principal forms considered constitute the primary permanent wall for the below ground construction, and are taken as diaphragm walls, contiguous or secant piles (which may be installed in different configurations) or steel sheet piles.

3.5 ground barrier

impermeable barrier between the structure and the ground intended to prevent or impede the ingress of water, dampness, radon, methane and other ground gases and contaminants

3.6 loading coat

layer of material designed to hold a Type A waterproofing material in place when resisting water pressure

3.7 perched water table

reservoir of water in the ground maintained permanently or temporarily above the standing water level in the ground below it, and is caused by the presence of an impervious soil or a stratum of low permeability

3.8 seepage

slow transmission of water through discrete pathways of a structure

NOTE This can also be known as weeping, as defined in ICE publication, Specification for piling and embedded retaining walls [1],

3.9 tanking

application of an appropriate waterproofing barrier to the walls, the base slab and, where relevant, the roof of a below ground structure, such that the entire envelope of the structure below ground is protected against water ingress

NOTE A cavity drain membrane is not considered to constitute tanking.

3.10 Type A (barrier) protection

protection against water ingress which is dependent on a separate barrier system applied to the structure

3.11 Type B (structurally integral) protection

protection against water ingress which is provided by the structure

3.12 Type C (drained) protection

protection against water ingress into usable spaces which is provided by the incorporation of an appropriate internal water management system

3.13 vapour check

membrane or other element that restricts the transmission of water vapour

3.14 waterproof

impervious to water

NOTE This can also be known as "watertight".

3.15 waterproofing

application of waterproof/water-resisting materials

3.16 waterproofing barrier

material that does not permit the transmission of free water, but might allow some water vapour permeability

3.17 waterproofing system

materials and methods used to protect a structure from water ingress and might also provide resistance to the diffusion of water vapour

3.18 water resistance

ability of a material to resist water penetration

3.19 waterstop

material designed to inhibit the transmission of water through joints in the structure

3.20 water vapour

water in its gaseous state

3.21 water vapour resistance

ability of a material to resist water vapour penetration

BS 8102:2009 Code of practice for protection of below ground structures against water from the ground