Joint Sealing

At joints, different components meet. It is at joints where a building is weakest to leakages. Joint sealants need to be correctly specified to keep building structures tight during their lifespan. Joint sealants are used to fill cavities permanently, keep joints, often with unusual shapes well-insulated, especially against acoustic or thermal transfer. Joints should allow for the needed movement of materials but must be water, air, heat, cold, and vapor tight. Joints must have movement capability, particularly in wood construction.

Sealants must show good adhesion to a wide range of materials, including concrete, masonry, painted wood, coated or galvanized aluminum, steel, and PVC. This is important for windows, doors, and other installations. Sealants are applied to facades and also inside buildings, particularly where volatile organic compounds (VOCs) may prove an environmental and regulatory issue, particularly if green-building requirements must be met. They must adhere well to components of the joints and allow for over-painting. The acoustic, thermal insulation, energy efficiency, fire resistance, water-tightness, and aesthetics must all be taken into account when specifying joint sealants.

Polyurethane sealants are used for porous substrates like concrete, bricks, and masonry. Silicone joints sealants are recommended for non-porous substrates like metal and glass. Silane-modified polymer sealants are best for window applications. Joint tapes, water bars, and swellable and injection systems are often used for joints wide in size.

The sealing of construction and movement joints is key to professional waterproofing design. Holderchem offers a range of rubber tapes and adhesives for surface application over joints and cracks, as well as swellable waterstops to be cast into the concrete in construction joints. It also offers joint fillers, which are durable and at the same time flexible enough to accommodate traffic shortly after being installed.