What type of joint is installed between a patio slab and building walls?

An isolation joint is specifically used between a patio slab and building walls to accommodate the independent movement of both structures. This type of joint allows for differential movement caused by temperature changes, settling, or other factors without causing damage to either the patio slab or the building structure.

The isolation joint serves to separate the concrete from the adjoining structures, preventing cracking or other structural issues that might occur from stress or movement. This flexibility is crucial in ensuring that the elements can move without restrictions, thus extending the lifespan of both the slab and the walls.

In contrast, a contraction joint is designed to control cracking that occurs due to the shrinkage of concrete as it cures, while a control joint also helps manage cracking but is mainly related to managing tensile stress. A construction joint indicates a planned interruption in construction but does not serve the specific function needed between a slab and a wall.