Elevated Plaza Deck Waterproofing

Many buildings and associations are constructed with a structural concrete deck above one or more levels of subterranean parking or other facilities. The plaza deck is generally the common area and is enriched with walkways, landscaping, planters, exterior lighting, and sometimes amenities such as tennis courts, swimming pools or spas.

 

Plaza decks are typically public areas accessible to pedestrians and in some cases vehicles that are located at or above grade level. They provide a functional or aesthetically pleasing element to any construction project which, at first glance, may not look like a waterproofing project.

 

Call us as we’ll inspect your plaza deck building system in order to help you understand how it was originally constructed, expectations for its life expectancy, how to extend the life of the system, and ultimately how and when to replace the waterproofing.

 

The purpose of the waterproofing is to protect the structural slab from water infiltration, and to protect the subterranean garage or finished building space below. The cost of replacement of the waterproofing layer is generally very high, mostly due to the fact that there is so much exterior finish in the way that will have to be removed and replaced just to get to the waterproofing layer.  Please visit our Parking Garage Deck Waterproofing page for more detailied information specific to garages.

 

We have seen many buildings where the subterranean levels show signs of water infiltration such as leaks, rust and spalling concrete. Rebar rusts when it is attacked by water. Rust takes up more volume than normal iron, so it expands and breaks the surrounding concrete. Cracked concrete often creates further water infiltration, causing more rust, and so the cycle continues.

 

Building owners often ignore these signs of water infiltration or install bandaids such as concrete spall repair performed from below, or even installation of troughs to catch leaking water or even falling chunks of concrete. Is it possible to fix a leaking structural deck from below? If you had a roof leak in your home, would you paint the ceiling? Typically these efforts only move the water to another location and do not solve the problem. Ultimately, over many years, the structural integrity of the deck becomes compromised.

 

Owners and managers should take proactive steps to lengthen the life expectancy of their plaza deck waterproofing. Irrigation and landscaping should be monitored regularly and trees and plants with invasive roots replaced. Renewing the top coat of deck membranes can lengthen the life expectancy. Many commercial deck coating systems require replacement of the top coat every 4 years, which if performed routinely, can greatly extend the life expectancy of the system.

 

Once water infiltration has started, it is best to have the situation professionally assessed. In some cases it may be possible to abandon the original waterproofing membrane sandwiched below and install a new layer higher up in the system. In most cases, however, there is little choice but to remove plaza deck landscape and hardscape and install a new system entirely. This significant expense is rarely forecast, and owners and managers would be wise to plan for this capital expense as early as possible.