Problem Solved! Leak Challenges

Water, water everywhere. Leaks are a major problem in co-op and condo buildings throughout New York City, and we recently dealt with two interesting cases. The first building had a long history of serious leaks after major, wind-driven storms. We started by inspecting apartments where we had complaints, and we found really moist, wet plaster conditions inside the apartments. We found this throughout the 17-story building, even on low floors, which is unusual. The upper floors usually receive the brunt of the damage. We estimated there was leakage from about 50% of the exterior wall surface area of the building, and that's a very high percentage. Typically, in prewar buildings you see 5%. So this was a major problem, and it required a major fix.
Costly solution. I’m going to back up a little bit. Prewar masonry buildings depend on the bricks and on the mortar that the bricks are laid into to provide the waterproofing for the walls. So we tested the mortar on this building, and we found out that it was a mix that did not have much of the binders— namely lime and cement — that are normally used in mortar. The building was built during the Depression, and the contractor had cut corners by using more sand and less cement and lime.
As a result, we believe the building probably started having leaks right after it was built. So the solution was to remove the outer layer of brick. We installed a waterproof membrane system and then we installed a new layer of bricks on top of it. We did that all over the building. In the industry that's called re-skinning, and it was a very expensive solution — about $4 million, which worked out to $50,000 for each of the 80 apartments.
An unconventional approach. The second building also had leaks from wind-driven rains. Again, we surveyed the apartments and found that about a third of them had leaks, and we estimated that we were getting water damage from about 10% of the exterior walls, and in much more scattered areas than at the first building I described. Re-skinning wasn’t warranted, so we took a different approach: We did the waterproofing from the interior rather than the exterior. We went into apartments that had leaks, and we removed the damaged plaster and then put in a waterproof barrier on the exposed inside brick layer of the outside wall. That barrier was a cement-based layer of basically stucco. And rather than re-plastering the interior walls, we put in a moisture-resistant wallboard. It stopped the chronic leaks. It’s been up for several years and has held up very well through wind-driven rains.
The work was intrusive, and it was not inexpensive. It came out to be about $10,000 per apartment that had leaks — which was one-fifth to one-third as much as a conventional targeted exterior repair project would have cost.
Turn every stone. I recommend that if you have leaks and know you are going to be doing an exterior repair project, you should survey all the apartments, because a lot of shareholders and condo-unit owners may not notice that they have water damage. And if you do an exterior repair project and then a year or two after it is done somebody says, "I have water damage," then it's really too late to go back and repair the walls from the exterior. The only alternative at this point is to do these interior type repairs. So before the work begins, the board should always survey every unit and make sure it knows where the damage is.