Plastic Expansion Joint Caps

A PVC expansion joint is typically a rigid plastic profile used to create a controlled gap in concrete slabs, allowing them to expand and contract with temperature changes. While effective for concrete, our WEATHERCAP® system is specifically designed for masonry. It uses soft, flexible lead that creeps into new joint configurations, maintaining a permanent, watertight seal as the building moves, which is crucial for historic structures.

The best sealant depends on the specific masonry type, joint size, and expected movement. However, our WEATHERCAP® system is designed as an essential adjunct to enhance the performance of any high-quality, compatible masonry sealant. It works by protecting the sealant from exposure and reducing the effective joint opening, which prolongs the sealant's life and ensures a more durable, weather-resistant joint regardless of the specific sealant used.

The system is made from soft lead, which has a low elastic modulus. This allows it to remain flexible and 'creep' into new joint configurations as a building naturally settles or moves. Unlike rigid materials that can crack or pull away, our lead caps deform with the joint, maintaining a continuous, unbroken seal that prevents moisture penetration over the long term. This is a key benefit for preserving historic masonry.

Absolutely. While it is renowned for historic preservation, WEATHERCAP® is also an excellent choice for new construction projects. Integrating our joint protection system from the outset ensures maximum longevity for masonry joints, preventing future moisture issues, reducing long-term maintenance costs, and extending the life of the sealant right from day one. Our A-2 Type A cap is specifically designated for new-construction installations.

We offer two primary configurations to suit different joint geometries. The Type A cap is a flat profile designed for joints between masonry units that are in the same plane, such as on copings or lintels. The Type B cap has a 90-degree cove shape, making it ideal for right-angle joints, like where a window sill meets a wall or at corner junctions. This ensures a proper fit and seal for various architectural details.

Yes, when handled with standard precautions. As with any lead product, proper personal protective equipment, such as gloves, should be used during installation. We advise washing hands and body thoroughly after handling, in accordance with OSHA regulations (29 CFR 1910.1025). When installed, the lead cap is stable and poses no risk, as it oxidizes to a neutral, protective grey finish that is safe and durable.