Asbestos Expansion Joint

Asbestos expansion joints are compressible filler strips or boards manufactured from asbestos fibre, typically chrysotile, bound with bitumen, rubber, or other flexible binders. They were inserted into gaps between sections of concrete in floor slabs, walls, bridges, car parks, and other structures to accommodate thermal expansion and contraction. Asbestos content ranges from 10 % to 50 % depending on the specific product.

Expansion joint fillers were widely used from the 1930s through the mid-1980s in commercial, industrial, and infrastructure construction. Their role was to fill the predetermined gap between concrete sections while remaining compressible enough to absorb movement without cracking. Asbestos was added to provide durability, dimensional stability, and resistance to moisture and biological degradation.

The material is classified as non-friable when intact. The asbestos fibres are bound within the bitumen or rubber matrix and are not released during normal service. However, the material becomes hazardous when it is disturbed, cut, drilled through, or removed during renovation, demolition, or structural repair work. Core drilling through a concrete slab that intersects an expansion joint, for example, can release asbestos fibres from the filler material.

Asbestos expansion joints are frequently overlooked during building surveys because they are concealed within the building structure. They may only become apparent when floor finishes are lifted, concrete is cut or broken, or when expansion joints are being resealed. A thorough refurbishment and demolition survey should specifically target expansion joint locations.

Modern expansion joint fillers are manufactured from polyethylene foam, cork, rubber, or bitumen-impregnated fibreboard without asbestos. When replacing asbestos expansion joint material, the old filler must be removed under controlled conditions with appropriate PPE and disposed of as asbestos waste.