The Finish Line: Katrina One Year After
First, you can go to New Orleans right now and have a good time, at least in the popular tourist areas, which look like nothing ever happened. But if you drive a little way from those restored areas, it's a different story. There are blocks and blocks of abandoned single-story houses and there are shopping areas that look fine, except a lot are not open. These buildings are in the areas that were flooded and stayed submerged.
New Orleans is not a town that is inundated with EIFS buildings but there are quite a few scattered around town. In a nutshell, the façades fared well. However, there are some aspects of the façades that did not fare well, not so much due to the EIFS itself but to the wall in general. What follows are some examples. These comments apply to EIFS not just in the Gulf Coast but in any area or wall design that has similar conditions-wicked weather and floodin
At gradeSome parts of the New Orleans area were underwater for a week or more. When EIFS was in these areas, it was not just wetted, it had the time to soak-up water (and whatever was in the water). So did the substrate. I removed a few such areas and found substrates that were basically mush.
To fix these areas, the sheathing and EIFS were removed and replaced (the studs, once they were fully exposed and could dry out, were usually OK). The moral: Even though these wall areas may look OK from the outside (the EIFS was stained but still attached to the wall), the wall behind may be a lost cause, and the EIFS and supporting structure may need to be replaced.
Along the same lines, in the coastal South it is not uncommon to use block or concrete near grade. One of the reasons is simply durability but termites and resistance to water are other good reasons. When EIFS is attached to these walls, it generally stays well bonded, even if submerged for days. But when removing the EIFS to see how well attached it really was and to check the condition of the substrate, I noticed that there was a lot of nasty stuff left in the space between the EIFS and block. This was what was causing the foul smell inside.
Apparently this gunk rose up inside the wall due to the flooding, and stayed there after the wall drained and tried to dry out. The supporting wall was usually sound, so the repair technique was to remove the EIFS to a level a few feet above the high water mark, let the wall dry for many weeks, and then reinstall the EIFS. The moral: Just because the wall that supports the EIFS is sound and the EIFS is still well-bonded, there may be nasty stuff still in the wall that requires removing and replacing the EIFS.
MoldIf you've ever been to New Orleans in the summer, it can get pretty muggy and stays that way for weeks on end. It's not surprising that mold is an issue in the area and Katrina did not help that situation. Here's what has happened.
Many buildings were abandoned either before or right after Katrina, due to storm danger, lack of power, or water or martial law. This went on for weeks in many cases, and some are still unoccupied. Some of these buildings are mid-rises and look OK from the outside but in fact are empty, as repairs are still being made to get them running again. Some of these buildings have essentially been sealed-up for months, with no ventilation or air conditioning. Additionally, many of these buildings had severe water leaks and the interiors got soaked, especially carpets and stud walls. The result is a terrarium-like atmosphere that has been going on for months, and mold abounds.
The presence of mold makes repairs more difficult as there are health and safety issues involved. This includes not only working around the mold but also what to do with the smelly debris. The moral: If a building gets inundated with water, as soon as you can, you want to get rid of all the wet stuff and ventilate the structure to dry it quickly.
Previous damageA factor that complicates the ever-present issue of who pays for the damage (insurance) is the question, "Is this the result of Katrina or is it a pre-existing condition?" Obviously, a wall that got torn off by Katrina's wind is not pre-existing but when you open up some walls you find all sorts of damage that looks like it's been around for years. That's when the "who-pays" arguments start.
An example of this is heavily rusted steel studs that clearly had been rusting for a long while, due to some source of water-probably small, unnoticed leaks over a long period.
Similarly, the hot, humid Gulf Coast climate makes the moisture in the air want to migrate toward the cooler, drier indoors. In stud walls, this can result in condensation (and mold) on the cavity side face of the interior walls. Some of this was quite extensive in buildings I've seen, and clearly did not occur simply as a result of Katrina. In some cases it occurred in protected areas where there were no water leaks at all-the moisture source was not the Katrina storm.
The "reservoir capacity" conceptI met some people in mid-rise buildings who toughed it out and stayed in their homes during the storm. They had some wild stories. Some said they had no leaks, but most said they had lots. Some were surprised that leaks had occurred when there hadn't been any in the past. Gee, was Katrina a major storm or not? There are reasons for this that goes beyond the extreme wind speeds and high rainfall rate.
Here's one factor: Most walls have the ability to absorb some water without harm and this absorbed water is not noticed because it stays within the wall-doesn't cause drips that you can see. There's a point, however, when the amount of water in the wall exceeds the wall's capacity to absorb it and then the leaks appear. This characteristic is sometimes called the "reservoir capacity" concept. Some walls, such as concrete, hold little water (they're solid), while various forms of cavity wall construction can hold a lot. Hence, it's possible to have leaky walls for years and not notice it; the water is there but is out of sight.
In walls that contain water sensitive materials, this can be a problem, as the repeated wetting, and perhaps extended periods of dampness, can slowly ruin the wall. This is especially true in areas where the drying potential is low due to high ambient outdoor humidity for extended periods, such as the Gulf Coast and the Pacific Northwest. Wall constructions that are "tight" and do not have inherently high ventilation rates can have this problem.
How EIFS faredOn all the EIFS-clad buildings I've seen, the main source of water entry was not the EIFS itself (it did not crack or leak itself) but the windows, sliding glass doors on balconies, failed sealant joints and bad flashings. Even given the reported 120-plus mile per hour winds, limber steel stud wall framing fared well-the EIFS moved a lot but did not crack.
Many of the EIFS jobs I've seen date back a decade or more. Interestingly, right next door to a damaged 20-year-old EIFS building, is a brand new EIFS structure of the same height (200 feet) that has EIFS with drainage. It was basically unaffected by Katrina and never had to be abandoned, except briefly when martial law was declared right after the storm due to looters. There was only limited water intrusion to the interior. This is an indication that refinements to the design of EIFS, as a wall system, are paying off.
Generally, the EIFS-clad buildings I viewed seemed to have fared well in the sense that the walls were intact. The problem, though, is more insidious, as lurking behind the "looks-OK" walls is often hidden water-induced damage that is hard to detect and expensive to fix. This is where the building envelope consultants come in and help assess the state of the façade, and figure out how best to fix it. It's interesting work but sad sometimes, as you realize that some owners haven't been home for a year.