Expansion joint filler board, also known as expansion joint foam or expansion joint filler, is a compressible material used to fill and protect expansion joints in buildings, bridges, roads, and other structures. Expansion joints are gaps between two structural elements that allow for thermal expansion and contraction, as well as movement due to other factors such as wind, seismic activity, and settlement.
Expansion joint filler board is typically made from closed-cell polyethylene foam, which is resistant to water, chemicals, and most common solvents. It is available in a range of thicknesses and widths to suit different joint sizes, and can be easily cut to fit the required dimensions.
The primary function of expansion joint filler board is to prevent debris, water, and other foreign materials from entering the joint, which can cause damage and corrosion over time. It also provides a compressible buffer that allows for movement and expansion without causing stress on the adjacent structural elements.
When installing expansion joint filler board, it is important to ensure that it is firmly compressed in the joint to prevent it from popping out. The filler board is typically covered with a joint sealant or other type of flexible seal to further protect the joint from the elements. Proper installation and maintenance of expansion joint filler board can extend the lifespan of a structure and prevent costly repairs in the future.