THE IMPORTANCE OF MOVEMENT/ EXPANSION JOINTS

WHAT IS STRUCTURAL MOVEMENT?

Subsidence, settlement, heave, sway, bouncy floors, bulging walls, cracks, expansion and contraction are all forms of structural movement. Such movement occurs all the time, and usually its magnitude is so small it passes unnoticed.

WHY DO WE NEED MOVEMENT / EXPANSION JOINTS?

The Architect or Structural Engineer should have incorporated movement joints at the design stage. Generally with larger floors the tiling will be divided up into sections (bays) and movement joints placed approximately every 8 - 10m. On walls at all internal vertical corners and at 3 - 4.5m centered vertically & horizontally.

Movement joints should be located in the tiling installation to coincide, and be continuous with, all existing structural movement joints, although they will actually be formed as separate joints isolated by a suitable thickness of backup materials. Essentially, any movement joints within the substrate should be followed through to the surface. In addition to movement joints to coincide with those in the concrete sub-base the Designer will normally specify that additional movement joints within the tiling be positioned at the following locations:

• Over existing structural movement joints.
• Where tiling abuts other materials.
• Where tiling is continuous across a junction of different materials or backgrounds.
• In large tiled areas and at all vertical internal corners and at 3m to 4.5m centered vertically and horizontally.
• Where any stresses are likely to be concentrated.
• Where large degrees of thermal movement or vibrations could be experienced.

A movement joint is simply a joint between tiles or between tiles and abutting surfaces that is filled with a resilient material instead of a hard caulk. On floor and wall installations, movement joints eliminate hard-surface contact that can damage the tiles, the structure, or both.

Modern buildings are designed to move slightly, and if you install tiles to accommodate this movement, you should experience few problems or complaints. If, on the other hand, you set tiles directly against abutting surfaces, or fill joints in the movement zones with hard grout without incorporating movement joints, you should expect to see cracked and powdery grout, cracked and loose tiles.

In fact, movement joints are one of the secrets to building long-lasting tile installations.

Movement joints do not eliminate movement, but instead, provide the space and the means for normal movement to occur unnoticed and without causing damage.

As with any other installation material, using premium movement joint fillers should provide increased longevity

Last Updated ( Wednesday, 11 November 2009 12:20 )