Project Overview:

Zavza Seal completed supplemental waterproofing work on an exterior staircase where water continued to enter the vestibule below.

The staircase had previously received surface waterproofing, but continued water intrusion showed that additional repairs were needed. Follow-up inspections found that several existing joint finishes had deteriorated or failed.

Rather than applying another surface treatment alone, Zavza Seal addressed the damaged joints and added another layer of waterproofing to the approximately 70-square-foot staircase.

The Problem:

Continued Water Intrusion

Water was still getting through the exterior staircase and reaching the vestibule below.

The original waterproofing had helped protect the staircase surface, but the continued moisture indicated that some areas required more extensive repair.

The main concern was the condition of the existing joints. Several joint finishes had deteriorated, creating potential pathways for water to enter the structure.

Deteriorated Joint Sealants

The existing joint materials were no longer providing the protection needed.

Joints are important areas to inspect during concrete waterproofing because movement and exposure to weather can cause sealants to deteriorate over time.

In this case, the failed joint materials needed to be removed instead of simply covered with another layer of waterproofing.

The Solution:

Removing Failed Joint Materials

Zavza Seal mechanically removed deteriorated and failing joint sealants throughout the affected staircase areas.

Once the old materials were removed, the exposed joints were ground, cleaned, and prepared.

This created sound bonding surfaces for the new waterproofing sealants.

Installing New Flexible Waterproofing Sealants

New exterior-grade flexible waterproofing sealants were installed into the prepared joints.

The flexible sealant was used to provide protection at the joints while allowing the material to accommodate normal movement.

The repair included vulnerable areas such as transitions, perimeter joints, and the connections between the stair treads and risers.

Supplemental Concrete Waterproofing

After the joint repairs were completed, the staircase surface was prepared for additional waterproofing.

Zavza Seal applied two additional coats of Radon Seal across the approximately 70-square-foot staircase surface.

RadonSeal is a penetrating concrete sealer designed for interior and exterior concrete. According to the manufacturer’s application guidance, the surface needs to be properly cleaned and prepared before application so the sealer can penetrate the concrete. 

The additional treatment provided another layer of protection against water moving through the concrete surface.

Front Door Lintel Waterproofing

The project also included waterproofing work around the lintel above the front door.

Old and deteriorated sealants were removed from the area above the entrance.

The exposed area was prepared, and new weatherproof sealants were installed to help protect the entrance from water intrusion.

The Result:

The supplemental waterproofing addressed the areas that were allowing continued water intrusion.

Failed joint materials were removed and replaced with new flexible exterior-grade sealants. Vulnerable staircase joints and transitions were detailed, and two additional coats of penetrating concrete sealer were applied across the staircase surface.

The work also improved the weather protection around the front door lintel.

The result was a more complete waterproofing treatment designed to reduce water entry through the staircase and its vulnerable joints.

Why Staircase Joints Matter in Waterproofing?

Exterior concrete stairs are exposed to rain, snow, freezing temperatures, and repeated moisture exposure. Joints and connections between different sections can become vulnerable as existing sealants deteriorate.

Proper surface preparation is also important when applying penetrating concrete sealers. RadonSeal’s installation guidance states that concrete should be clean, bare, and porous enough for the product to penetrate properly. 

For this reason, the solution for this staircase involved more than adding another coating. The deteriorated joint materials were removed first, the joints were repaired, and the concrete surface then received supplemental waterproofing.

Exterior Staircase Waterproofing

Water intrusion through an exterior staircase can eventually affect the space underneath if vulnerable joints and concrete surfaces are not properly protected.

This Brooklyn-area project required a targeted waterproofing approach that combined joint repair, flexible sealants, concrete waterproofing, and entrance weatherproofing.

Zavza Seal provides waterproofing and concrete repair services for residential and commercial properties throughout New York.