NHBC Standards 2006

4.4 Strip and trench fill foundations


4.4 - M1Materials standards
4.4 - M2Concrete
4.4 - M3Reinforcement
4.4 - M4Other materials

4.4 - M1
All materials shall:
(a) meet the Technical Requirements
(b) take account of the design

Materials that comply with the design and the guidance below will be acceptable for both strip foundations and trench fill foundations.

Materials for strip and trench fill foundations should comply with all relevant standards, including those listed below. Where no standard exists, Technical Requirement R3 applies (see Chapter 1.1 'Introduction to the Standards and Technical Requirements').

References to British Standards and Codes of Practice include those made under the Construction Products Directive (89/106/EEC) and, in particular, appropriate European Technical Specifications approved by a European Committee for Standardisation (CEN).


4.4 - M2
Concrete shall be of a mix design which is suitable for the intended use

Items to be taken into account include:

strength to safely transmit loads
durability against chemical or frost action

For guidance on the specification and use of concrete, particularly in relation to the choice of mix to resist deterioration due to ground aggressivity, reference should be made to Chapter 2.1 'Concrete and its reinforcement' (each section).


4.4 - M3
Reinforcement shall be sufficient to ensure proper transfer of loads

Where reinforcement may be necessary, for example at construction joints or over small localised soft spots or changes in bearing strata, it should be in accordance with Chapter 2.1 'Concrete and its reinforcement' (each section).


4.4 - M4
Compressible materials shall be capable of absorbing potential heave forces, where appropriate

Proprietary materials should have been assessed in accordance with Technical Requirement R3.