Technical Guide

Part 2 The Language of Clay Bricks

Part 3 Product Specification and Physical Properties

3.1 Overall dimensions and tolerances
3.2 Warpage and tolerance
3.3 Brick strength
3.4 Efflorescence
3.5 Irreversible moisture expansion
3.6 Other properties

3.6.1 Durability: Selection criteria
3.6.2 Initial rate of absorption
3.6.3 Fire resistance
3.6.4 Acoustic insulation
3.6.5 Thermal proper ties

Part 4 Accommodation of Movement

4.1 Overall movement
4.2 Thermal movement
4.3 Irreversible moisture expansion movement
4.4 Moisture content movement
4.5 Movement in adjoining structures
4.6 Provision of control joints

Part 5 Structural Masonry with Clay Brick

5.1 Structural design requirements
5.2 Empirical design

5.2.1 Building limitations
5.2.2 Strength requirements for masonry units and mortar
5.2.3 Dimensions of masonry walls in buildings
5.2.4 Empirical rules for foundations Foundation preparation Minimum width of strip foundations in single storey structures Compaction
5.2.5 Minimum thickness of foundation walls
5.2.6 Free-standing walls
5.2.7 Retaining walls

5.3 Rain penetration requirements
5.4 Mortar

5.4.1 Mix proportions
5.4.2 Cement
5.4.3 Lime
5.4.4 Sand
5.4.5 Mortar plasticisers
5.4.6 Pigments
5.4.7 Ready-mixed mortar

Part 6 Cleaning of clay brickwork

6.1 General precautions
6.2 Preparation
6.3 Mortar and mor tar smear
6.4 Lime and lime blooms
6.5 Vanadium
6.6 Efflorescence
6.7 Lichens and mosses
6.8 Running water
6.9 Various oils
6.10 Paint
6.11 Rust or iron
6.12 Manganese
6.13 Timber
6.14 Smoke and soot
6.15 Tar
6.16 Large projects – multi-storeyed buildings

Part 7 Construction Details


The contributions of John Lane and Paul Boucher (Boutek division of CSIR) are gratefully acknowledged. In addition, the Clay Brick Association extends its thanks to: The Joint Structural Division of the South African Institution of Civil Engineering and the Institution of Structural Engineers for assistance and constructive comments over the years.

The SABS, CSIR and the National Home Builders Registration Council for their documents that have been used throughout the preparation of this document.

Numerous other CBA members who have, over the years, played a part in developing the Technical Guides.