Expansion Joints Since all materials expand and contract due to temperature and/or moisture, the use, location, and design of expansion joints, especially in the roof structure system, should be taken into consideration by the roofing system designer at the time of original building design. Although provisions for adequate expansion joints are the responsibility of the building designer, Koppers offers the following suggestions for the protection of the roofing system against splits or other problems caused by expansion and contraction. Roof expansion joints are recommended: Where expansion joints are provided in the structural system. At all places where the structural supports and roof assembly change direction. Where type of adjoining deck materials change. At intersections between new and old buildings. At junctions where interior temperature conditions change. On areas larger than 200 (61m) continuous feet in any direction. Where movement may occur between vertical walls and the roof deck. Where control or expansion-contraction joints are provided in the structural steel, deck material, or deck system, provisions must be made for continuation of this relief through the built-up roofing system. Koppers realizes that in a climate-controlled building there may be little or no expansion AFTER the building is in use; however, building expansion joints are still recommended. Koppers recommends curb type expansion joints as referenced in Detail B.7. Koppers will not be responsible for any damage caused by such expansion and contraction.  Return to General Requirements and Considerations for the Designer