Expansion Joints

Especially in commercial and large public buildings, expansion joints provide a vital component in designs involving materials which may expand or contract when exposed to heat or cold cycles of the surrounding environment. The flexible nature of expansion joints allows materials to move slightly without damaging surrounding or adjoining materials, and provides for the natural expansion and contraction movements without compromising the overall structure of the building. It also acts as a heat absorber, allowing differences in temperature to be mediated effectively. Expansion joints may be used in any residential or commercial building regardless of materials, but are especially effective in steel and concrete structures, where even minor change sin temperature can cause expansion and contraction of the materials.

Expansion joints and asbestos

Like many construction materials manufactured prior to 1977, expansion joints relied heavily on the inclusion of asbestos fibers during the manufacturing process, to make these joints flexible, strong, and heat-resistant. Because expansion joints must be flexible in order to work properly, and because their purpose is to disperse heat successfully, their very nature means they must be manufactured from components that suit these requirements. Certainly, asbestos must have seemed like the perfect component. In addition to its high tensile strength, flexibility, and heat resistance, asbestos was widely and inexpensively available. The inclusion of asbestos in the manufacture of expansion joints must have seemed like a “no-brainer.”

But as the health risks associated with the use of and exposure to asbestos became more widely known and accepted, the federal government responded by outlawing the use of asbestos in any construction material, beginning in 1977. The same legislation allowed existing stocks of asbestos-based materials to be used until they were depleted, which means that any building constructed prior to the mid 1980s may – and probably does – contain asbestos materials.

Anyone involved in the manufacture or initial installation of these materials has had exposure to the embedded asbestos fibers. Any renovation or restoration on these buildings causes additional risks to contractors, as well as those who live or work in or near the renovation site. Moreover, because asbestos breaks down over time, materials containing asbestos may begin to degrade without the disruption of renovation, releasing the potentially deadly fibers spontaneously through the natural process of disintegration.

Last modified: December 09 2009.