A planned separation extending completely through a concrete slab, masonry wall, or bridge deck. It is filled with a flexible material that compresses and expands, allowing the rigid building materials to move with temperature changes, moisture shrinkage, or seismic shifts without buckling or cracking.
Heard on the job
Make sure the concrete guys install the expansion joint material before the slab cures too much.
Insider tip
Expansion joints go all the way through the material to separate it into independent blocks, whereas control joints are just shallow cuts meant to guide where inevitable cracks occur.
Also heard as
- movement joint
- isolation joint