Building Management Hawaii April/May 2014 - (Page 20)

ConCrete Maintaining A Strong Foundation Below grade and at grade spall repairs are an important step in protecting your building. By Willie White W hen most people think of spall repairs, they look up along the sides of their buildings. Those spalls are important and should be fixed as soon as possible. What is equally important, however, are those spalls that most people don't see. These are the spalls in basement parking areas, basement storage closets, and those hard-to-find corners that are below grade. I'm sure everyone has heard the saying, "A building is only as good as the foundation it is sitting on." Then think about spalling happening in your building's foundation. You won't get a lot of salt air in your basement in Hawaii, but you can get an awful lot of ground moisture. That unchecked moisture can be as detrimental to the steel rebar as the salt air. Because these problems occur below grade, you're faced with two challenges: One is to repair the damaged concrete; the other, and more importantly, is to stop the moisture infiltration so the spalls don't reappear in the same spot several years down the road. The best and most effective way to stop the moisture is to excavate along the outside edge of the wall down to the footing. Remove the old, failed waterproofing, and then apply a new waterproofing system to the concrete. Don't forget to install protection board against the new waterproofing so backfilled rocks don't prematurely damage the waterproofing. Installing perforated drainpipes into the bottom of the trench and covering them with pea gravel is a great way to get rid of groundwater so it doesn't build up against the wall. While excavating is the best way to stop the moisture, it's not always possible to do it. The alternative is to waterproof the wall from the negative side. This can be accomplished in several ways. The use of penetrating sealers is one way, and the application of hydrostatic resistant coatings is another. Either way, something needs to be done. In most cases, a penetrating sealer is more effective because it'll stop the water from entering the concrete wall, thereby keeping the moisture away from the steel. Once you chip out the old spalled concrete and expose the rebar, it's best 20 April-May 2014 BMH www.buildingmanagementhawaii.com http://www.cpschawaii.com http://www.buildingmanagementhawaii.com

Table of Contents for the Digital Edition of Building Management Hawaii April/May 2014

Editor’s Note By Stacy Pope
Hawaiiana Hits The Big Five-0
CONCRETE Restoration and Repairs: Maintaining A Strong Foundation
Concrete Spalls, Cracks And Leaks
Should You Repair Or Replace?
Restoring Exposed Aggregate Surfaces
Preserving A Historic Treasure
ELEVATOR Modernization: Are You Losing Energy?
Greening Your Elevators
Upgrading On A Budget
INSURANCE: Locking Down The Leaks
Navigating Property Insurance
COOLING TOWERS: HVAC Chemical Feed Pumps
Waikiki’s Oldest Hotel Keeps It Cool
Industry News or Movers & Shakers
On Site: Self-Management 101

Building Management Hawaii April/May 2014