Movement Control

Accommodation of Movement

All Building materials are subject to movement due to temperature and moisture changes. Designers should therefore ensure that the effects of such movement are accommodated to prevent unsightly cracking which may further result in structural defects.

A number of factors should be considered by the designer.

• specifying a product with low drying shrinkage, e.g. Forticrete Masonry
• specifying the correct mortar
• providing control joints at suitable centres
• using bed-joint reinforcement
• protecting the blocks before and during construction

Detailed information is covered within BS5628: Part 3: 2005

Control Joints

Control joints are vertical separations built into a wall and located where cracking may occur due to excessive stresses caused mainly by drying shrinkage.

As a general guide the joints should be at regular spacing up to 9.0m in external walls and up to 12.2m maximum for internal walls. The table below outlines the recommended spaing for movement joints when using Forticrete Masonry.

For further details please see the section on Movement Control and Bed Joint Reinforcement in the Forticrete Design Guide.

Forticrete's Technical Department can offer guidance on the location of movement joints within a building. We will assess the drawings and then comment on the recommended location for movement joints - we would point out that the final decision on position should always be confirmed by the structural engineer for the project.

For further details call the Technical Department on 0800 262136.