New York City, NY

The concrete structural deck below the famous limestone steps at the entrance to the Museum had never been water-proofed. A project was undertaken to remove and restore the steps. As part of the restoration project, it was decided that it would be wise to install a long term waterproofing membrane prior to replacing the stair treads.


A liquid waterproofing membrane was sought that would be able to conform to undulating concrete deck the as well as waterproof small dowels which were set in the deck to hold the treads in place. Initially a hot asphalt system was chosen but due to complicated permitting and restrictions to place a kettle near the entrance, it was decided that a cold applied liquid system would cause less disruption to the facility. Ultimately, the Sikalastic RoofPro system was chosen because of its safe, cold application. It was also chosen because of its unique conformable fiberglass reinforcement, Reemat Premium. The reinforcement allowed the liquid membrane to conform to the irregularities of the deck as well as effectively waterproof a large number of dowels that presented the most difficult condition to waterproof on the project.


The Sikalastic Roof Pro membrane was applied to the concrete deck and then a layer of drainage mat was installed to both protect the membrane from damage and provide a drainage plane beneath the treads. A hydronic snow melt system was installed over the drainage mat and the restored limestone treads were set in a mud bed and keyed into the dowels.