Building separation joints divide large or complex building structures into smaller, discrete units that can move independently. These joints are categorized into three types: volume-change joints, settlement joints, and seismic separation joints.

Volume-change joints address the effects of expansion and contraction due to temperature and moisture variations. They are strategically placed at discontinuities in a building's mass where cracking is most likely and are spaced about 150 to 200 feet apart in elongated structures, with spacing tailored to the material properties and the extent of dimensional changes expected.

Settlement joints are used to prevent structural distress that can occur from differential settlement rates in different parts of a building. This situation can arise in structures with varying foundation types or those built on different soil conditions.

Seismic separation joints are specifically designed for buildings in earthquake-prone areas. These joints divide the building into smaller segments to ensure that each part can move independently during seismic events, minimizing the risk of damage.

Overall, building separation joints are implemented by constructing independent structures on either side of the joint, sometimes with completely separate foundations and structural elements, ensuring manageable movement in response to various forces.