A waterproofing system is designed to keep water out of the dry area and when this type of system fails it can cause problems.
WHAT WAS THE CHALLENGE?
Figure 1 Existing plaza deck before start of work
The client reported that there were leaks in their plaza deck and the soil in their planter beds were overly saturated with water. This indicated that the water was not draining properly and was pooling at the deck and waterproofing system. Most waterproofing systems are not designed to be exposed to water for long periods of time and will deteriorate where there is ponding water.
The leaks were located in the basement level mechanical, retail, and auditorium spaces beneath a concrete plaza deck made up of planters, paved walkways, and mechanical exhaust enclosures.
WHAT SERVICES DID GRLA PROVIDE AND WHAT DID WE FIND?
FIgure 2 Plaza deck with material and waterproofing removed
To determine the source of the leak, GRLA performed a survey of the deck from below and a series of exploratory openings above. Pavers and soil overburden were removed in select areas to identify:
the existing system used to waterproof the deck
how it was installed
the transitions between materials and surfaces.
Failure of the existing waterproofing system had already resulted in damage and costly repairs.
GRLA’s investigation found weak points in the transitions between materials which could deteriorate at an accelerated rate and areas of failure where exposed to the sun.[JS1] When the landscaping and overburden were removed, it was found that the existing system had begun to lose adhesion, and there were gaps in the system where water could bypass the waterproofing and travel into the concrete deck below.
WHAT WAS GRLA’S SOLUTION?
Figure 3 Plaza deck waterproofing installation
The plaza has short walls separating areas along with a curved walkway design, an extensive irrigation system, and mechanical curbs. A sheet applied membrane system was ruled out because it is difficult to install in a geometry that has multiple vertical and horizonal surfaces.
GRLA determined that the new waterproofing system in the mechanical space, planters, and paved plaza be a single product versatile enough to be installed in all three locations which would insure a single installer and uniformity of waterproofing. Because the waterproofing in the mechanical space was to be exposed to the sun, it was important that the system selected is not UV sensitive and could withstand the elements.
GRLA’s Building Envelope Sciences Project Manager, Ed Sprenkle, explains the rationale for the selection, “The decision was made to use a liquid applied waterproofing membrane with a thirty-year warranty. This provided the longevity needed for a system that is hard to access locations under concrete and landscaping and the resilience to handle the unique conditions of the site.”
Contact GRLA’s Building Envelope Sciences team - We are the specialists to assess, diagnose and recommend appropriate solutions for your building.