AAC Masonry Products
(continued)
Movement Joints
Accommodation of Movement
All building materials can move. This can be due to:
~ expansion and contraction (shrinkage) related to the physical characteristics of the materials and the environment
~ structural movement
Such movements are termed either reversible or irreversible. The accommodation of movement should be considered at the design stage for all masonry walls.
General Considerations
Normally dissimilar materials should not be bonded together. They should be separated by forming a vertical movement joint or by incorporating a horizontal slip plane, as appropriate.
Internals walls of low-rise dwellings do not normally require movement joints. The use of bed-joint reinforcement at openings is usually sufficient to avoid cracking.
With the exception of solid external walls with stucco, the provision of movement joints and bed-joint reinforcement at openings is normally required in walls with dry wall finishes.
Location Of Movement Joints
Where movement joints are required, they are best formed:
~ At intersecting walls, columns, and other structural members
~ At changes of wall height, thickness, or where chases occur.
~ To coincide with movement joints in adjacent elements of
structure (floor or roof).
~ At junctions of dissimilar materials.
~ Where architectural or structural features create a
change of section.
Note: Where a movement joint is required, but aesthetic or practical reasons do not allow (e.g. party walls, where a movement joint would impair sound insulation), the wall may be reinforced.
SafeCrete
Installation Manual
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