My cooperative building has a tight budget, yet we have a handful of exterior repairs that we've been putting off, including a leaky roof supposedly caused by cracks in the parapet and some badly worn sections of roofing membrane. One contractor told us that instead of replacing the entire roof, he could save us money by applying patches of tar on the problem areas and then fastening aluminum cladding over the parapet walls. Given our limited funds, we're considering going with these fixes to hold us over for a while. Are these options a cost-effective way to buy time, or are we just delaying the inevitable larger repair program?
Covering a deteriorated parapet with aluminum cladding is a futile method of trying to prevent water penetration.
While interim repairs can sometimes do the job for a short period of time when the deterioration is minor and limited in scope, the "repairs" your contractor is suggesting are the equivalent of putting a band-aid over a serious wound. Boards without much money to spend on maintenance and repairs are often tempted with the lure of so-called quick and easy fixes, but the funds spent on cutting corners would have been better put towards reliable, longer-term repair programs that will more conclusively address their building's problems.
Tarred and Weathered
Because roofs bear the brunt of a building's abuse, they're often subjected to many slap-dash patch-up jobs in ongoing, largely ineffectual attempts to stem leaks. One of the most frequent methods is to apply tar to the suspected problem areas. With the roof as their canvas, some contractors will tar everything in sight, including masonry, in the mistaken belief that the sealant is a reliable way of keeping out water.
Roofs are subjected to slap-dash patch-up jobs in trying to stem leaks.
Water, though, can find its way in through different entry points, so eventually the tar will fail to stop the leaks. What the tar will do, however, is trap the water in, preventing the masonry from breathing and drying out. When cold weather sets in, the settled water freezes and expands, cracking the masonry. Repeated freeze-thaw cycles eventually weaken the structural integrity of the masonry in parapet and bulkhead walls to the point where they may have to be rebuilt.
Clad Handling
Similarly, some contractors install aluminum cladding over cracked or spalled parapet walls (and often concrete balconies) to protect them from water infiltration. But like tar, the cladding's main effect is to keep water from escaping while only temporarily blocking it from entering, subjecting the masonry to the same freeze-thaw conditions. The cracks and deterioration will worsen underneath the cladding, while water will continue to slip in. Moreover, the cladding makes it more difficult to monitor the underlying conditions and head off further defects.
For parapet walls that have been tarred over or cladded and are still allowing leaks in, the tar should be scraped off and the cladding removed. Investigative probes should then be undertaken to determine the location of the leak so repair work can be properly performed.
Frequently the culprit of leaky parapets lies in deteriorated caulking in the coping stone cross joints. Caulking is easy to check, and at approximately $10 a linear foot to apply, it's much cheaper than the approximately $500 a linear foot it could cost to rebuild a parapet wall. Yet despite the importance of maintaining proper caulking, it's a low-profile item often overlooked in favor of tarring or cladding.
Still another overused cost-saving fix is repeatedly "capping" a roof by adding layer after layer of protective membrane. Capping can provide a supplemental measure of waterproofing if the underlying structure is sound, but it can't save a badly deteriorated and saturated system. If leaks persist after one or two caps then it's time to face the music and rip up the existing roof and lay down a new one. Keep in mind that repairing or replacing the roof itself isn't necessarily the answer to the building's water troubles. A new roof, no matter how good, won't end leaks if the roof-level masonry, including parapet walls, bulkheads, and chimneys, is deteriorated.
E-Z Roof Decks
Just as boards should be wary of ill-advised short cuts to roof repair, so too should they think twice before approving any type of slap-down roof deck installation. Laying down concrete or rubberized pavers or wooden slats on top of the existing roof does not automatically transform it into a proper roof deck system. The existing roof structure may not be built to handle the additional weight that recreational activity will impose, and the installation may run afoul of the New York City Building Code. Other elements that should not just be added to the roof without proper planning and design are planters, gardens, fences, railings, and anything else that may impinge on the roof by stressing its waterproofing ability and/or structural integrity.
Leaky parapets are often due to deteriorated caulking in the coping stone cross joints.
Aside from the roof, boards should be aware of two other areas commonly subjected to band-aid fixes and compromising short cuts: windows and pointing. Window replacement projects are expensive and time-consuming, so boards will naturally look for ways to save money and time. A cardinal sin when replacing windows is to choose a cheaper quality unit. Vinyl windows are the least expensive type, but they typically lack the structural strength and air and water tightness necessary for high-rise multi-dwelling buildings. Thermally insulated double-paned units with either aluminum or wood frames are the more reliable choice.
Even with proper-grade windows, poor installation will compromise their high-performance qualities. The window installer should be asked to provide a sample installation of each type of window being used so they can be tested in place and verified as meeting the specified performance ratings for structural pressure, water resistance, and air infiltration. Proper anchorage is one of the key factors: Windows that are screwed through the sash track lose their air and water tightness.
With existing windows, a fresh coat of paint only goes so far. Rotted or warped wood windows won't keep out the rain or cold and will eventually need to be replaced. The same holds true for the window lintel steel. Scraping, cleaning, and painting won't build up the portion of the steel already lost to rust.
Finger Pointing
Like caulking, pointing—the replacement of mortar between bricks—is an easily overlooked repair item. In a properly pointed building, the mortar surface in the joints should be concave so that water runs off the building without collecting in the joints, where it will seep into the bricks. Brick mortar joints undergoing repointing need to be cut at least ¾ of an inch deep to remove enough of the old mortar before applying a new layer. Often, however, contractors will cut a mere ¼ of inch deep, then smear on the new layer, sometimes with their fingers instead of a proper pointing tool. The result is a sloppy appearance and lesser waterproofing capability. The specifications for the repair work should clearly state the proper depth the brick mortar joints should be cut, and the project engineer should check the work when conducting site visits.
Band-aid fixes and cutting corners on repairs and installations may seem like a viable way out of a building's pressing problems, especially when funds are short or time is tight. But more likely they cause the underlying conditions to grow worse until the day of reckoning when a proper repair program will need to be undertaken—often at greater cost than it would have earlier on. Regular maintenance and careful budget planning will keep boards from the predicament of having to pay less now for more problems later.
Stephen Varone, AIA is president and Peter Varsalona, PE is principal of RAND Engineering & Architecture, DPC. This column was originally published in the October 2003 issue of Habitat Magazine.
