10. Rigid seals

Some joints or gaps between two building materials have, by their very nature, very low amplitudes of movement, or when the two materials move simultaneously in the same way, resulting in little or no change in joint width.

For example:

• concrete-concrete joints between walls and floors, and also, to a lesser extent, between concrete framing (walls + floors) and partitions (brick, plaster or plasterboard) and for low-rise buildings;

• joints between numerous adjacent elements, or between small elements such as bricks or tiles bonded to a concrete substrate that is itself subject to slight movement.

In these cases, the joints are made with cement mortar or plaster, which are rigid by nature and therefore cannot tolerate movements greater than 1 in 1,000....