New York's Cooperative and Condominium Community

Habitat Magazine October 2020 free digital issue

HABITAT

ARCHIVE ARTICLE

Roof Work

Call it "The Roofer's Maxim" or "The Warning from Above." According to Eric Cowley, principal of Cowley Engineering, there are two types of flat roofs: the roof that leaks and the roof that will leak.

Co-op and condo boards should take to heart this unsettling truism. Dealing with the roof is as inevitable and unavoidable as dealing with the weather. And when talking about roofs, weather is as big a factor as choice: when and how should you do a roof job? Like any other system in your building, the roof takes a certain amount of care. And the more attention you give to it, the better off you will be.

If your roof is the first type — leaking — you have three options: (1) repair (find the source of the problem and fix it); (2) re-cover (place a new waterproof membrane over the existing roof); or (3) replace (tear up the old roof and rebuild an entirely new one). Each option has its own set of costs and issues.

If your roof is the second type — not leaking — consider yourself lucky (temporarily) and put in place a program to monitor its condition and protect it from damage. A successful, proactive program will enable you to realize the full benefit of your building's investment. It might also lengthen the useful life of the roof and give you an even greater return on your money.

Out of Sight

Who ever thinks about the roof? It's up there, it's supposed to keep everything dry beneath, and it's a place to go to get a view of the city or to sunbathe. In reality, the roof is a moderately sophisticated engineered system integrated into the building structure. The classic built-up roof starts at the deck, the top concrete layer above the ceilings of the top floor. Two layers of a vapor barrier (such as tarpaper) are laid on the roof deck. Above that is a layer of insulation board at least an inch thick. Over the insulation are four layers of waterproof material, usually an asphalt-impregnated rubber material.

The materials are only part of the story. "How you detail the installation is critical," says Paul Millman, principal at Superstructures. A roof needs to be properly pitched, so that it sheds water. It also must be flashed with metal where it meets the sides of the building and around anything that projects through the roof, such as air vents and supports for structures above the roof, like water towers. "Extra care needs to be given to sealing the seams between the panels of the material as it is laid down," Millman notes.

The other essential elements are the parapet, drains, scuppers, and downspouts. The parapet is the section of the building's façade that rises above the roof level. It must be water-tight. The drains, scuppers, and downspouts, which carry water away and prevent pooling, are essential to the success of a roof.

"Most boards think of the roof as the black surface they can walk on," observes Stephen Varone, director of operations of Rand Engineering. "They should think about the 'roof level' of the building that encompasses all the structures that are up there, including bulkheads, parapets, and chimneys, all of which are places where water can get in if the masonry has failed. What most people think of as the 'roof' is really just the bottom of the roof level."

Testing, Testing

There is a giant misconception that when a leak appears inside a building, the roof has begun to fail. Not so, says engineer Alan Epstein, a principal in Epstein Engineering. "In reality, a leak appearing in an apartment means that the roof failed long ago and the water has just penetrated the last of three substructures. Water has passed below the membrane, through a parapet or found some other path into the insulation. It has penetrated through the insulation and is now coming through the deck into the ceiling or walls of an apartment."

When leaks start to appear, a building's board faces a serious challenge. "Don't try to diagnose a roof problem yourself," warns engineer Kurt Rosenbaum, the principal at KRA Associates. "Boards are made up of laypeople and they just don't have the expertise to figure out what is going on." By the time leaks appear, the required solution is usually beyond the ability of the super to repair. By all means, do not try and solve the problem by, as one engineer says, "putting tar on anything that doesn't move."

The quality of any decision a board makes is a function of the information the directors have before them. The value of knowing the whole story about the condition of the roof and any other factors (such as the condition of the parapet) that might contribute to the leakage cannot be underestimated. The most conservative course to take is to rely on a professional engineer or architect to provide a damage assessment and a comprehensive survey of the condition of the roof.

Before choosing an option, "you will need to do some testing," advises Roy Klein, an engineer with the Yates Restoration Group. There are destructive and non-destructive forms of testing. The objective of testing is to find out how much water has gotten into the roof and whether or not the problem can be contained. Tests can include taking core samples of the roof in various locations, opening up sections of the membrane to see what's below, and water-testing — flooding an entire section of the roof — to recreate a leak and isolate its location.

"The hardest part is determining where the water is coming from," admits Varone. "Never check for roof leaks without first making sure that everything else up there is sound, especially all of the masonry structures." If significant water seepage has occurred, repairing or recovering may not be feasible. Even if the leaks are all repaired, there will be ongoing problems from the water that is now trapped in the roof.

"Once water gets into the insulation material, it loses its value," says Varone. Any remaining moisture will still have to follow gravity and drain out. Thus, a board that chooses an option short of full replacement may find itself still dealing with leaks long after the surface repairs have been completed.

Repairing It

After the source of the leaks has been identified and it has been ascertained that the damage has been contained to a limited section of the roof, tearing up the damaged materials and patching the area may be the right solution. Such a situation might occur when lubricants from the elevator machinery have leaked onto the membrane and dissolved a portion. It might also occur in an area where foot traffic has been allowed and the damage is readily visible.

You may also end up in a situation where you have a known problem and a regular repair program buys time. That was the case with a 125-unit co-op on the palisades in the Riverdale section of the Bronx. "The leakage began when the roof was five years old," says Jeff Baxter, a shareholder who was on the board at the time. "The bolts that held down the insulation board were coming up through the membrane." The only existing warranty was on the membrane material, which hadn't failed.

The building found itself in an ironic situation. "The manufacturer said that if we continued to fix the problems with the bolts as they came up, they would continue to warrant the roof," Baxter recalls. "We had to keep repairing the roof in order to protect ourselves from the material ever failing. As long as the discounted value of the warranty was above the cost of repairs, we were ahead economically. It turns out, in hindsight, that we made the right choice. The continued repairs cost a couple of thousand dollars, but we got the full life out of the roof, and postponed having to make a major expenditure."

In buildings with budget constraints, repairs may be the only feasible solution. But the point is to be certain that the damage is contained and that the repair will be effective, because the risk is that the leaks will return and a larger job will have to be addressed.

Re-covering Roof

Roofs have a useful life of 10 to 25 years. If a roof fails during its lifetime and a survey is done that shows that the damage is limited, an alternative is to apply a new membrane over the top of the existing roof. "Once you have leaks, the chances are you are in serious trouble," Klein notes. "But if you do the testing and the roof is not water-soaked, you may be able to buy some time before you have to replace the entire roof."

Re-covering, though, has its risks. "Not too many years ago, we went through a period when there were a lot of disasters," says Millman. "Bad contractors were putting down covers everywhere because it was cheap." As a result, a number of roofs leaked. "They were single-ply materials and it was like putting a tire inner tube over the whole roof," says Cowley, referring to the same period in the late '80s and early '90s. "The material was 20 feet wide so you could cover a lot of area quickly and heat was not required in the application."

Unfortunately, the glues dried out and the seams came apart. "A lot of buildings lost money on those roofs because the companies that supplied them went belly up," according to Cowley.

Deciding on whether or not to choose this option depends on an assessment of the risks and rewards likely to be encountered. A re-covering may have a useful life of 12 years. Anything short of complete replacement contains the risk that you are paying to cover over a roof with a fatal flaw that will arise before the end of the new roof's useful life and that the money spent on re-covering will be lost.

The Replacements

Once water gets into the insulation, which is usually a fibrous material, it can transmit anywhere throughout the roof. "Water travels the path of least resistance," notes Varone, "and just patching above where there is a leak is probably not going to solve the problem."

Also, probes and tests can miss problems that will undermine the benefits of repairs and re-covering. The best, and most costly, solution is to tear up the entire roof, all the way down to the deck, and rebuild it entirely. "One of the benefits of a well-constructed roof with multiple plys of covering material providing redundant protection is that anybody can repair it," says Cowley. Another is a long useful life, 20 to 25 years, covered by a warranty.

Total replacement is no small undertaking and boards should be prepared. Unforeseen conditions that are not covered under the contract can add significantly to the project cost. "On one of our recent jobs, we were hired to strip off an old roof. What we found was that an 8-by-8 [-foot] skylight had been installed in an 8-by-10 [-foot] opening," says Richard Nagel, a principal in Nagel Roofing. The skylight was being held up by little more than the roofing materials. We had to rebuild the structure and reinstall the skylight. Other examples of conditions that have been uncovered in recent roof jobs around the area include a deteriorated roof deck requiring new concrete to be poured and mold growing under wooden roof decks.

The logistics of a replacement are also an issue. "It gets messy," says Klein. "You have a construction site in the middle of a residential locale. Getting the waste materials out is a problem. Also, you have to be sure to have a temporary covering to be sure that no water gets in during construction."

In addition, older roofs can contain asbestos. Some flashings and some of the insulation felts used in the past contained the hazardous material. In a total tear-up, steps have to be taken to be sure that such material is removed properly. That can add time and costs to the job.

The Price, The Professional

So what will this all cost? For a 10,000-square-foot-roof, the complete removal and installation of a new built-up roof can cost anywhere from $150,000 to $250,000. Professional fees of engineers and architects for full specs and drawings will run 12 to 15 percent of the total job for a project in the $250,000 range.

The engineer or architect should present the board with a complete report on the extent of the problem and prepare uniform specifications for the work to be done. The value of a uniform spec is that when the contractors' bids come in, the board can compare apples to apples and be sure that it is getting what it needs to solve the problem. The engineer or architect can also help in the analysis of the bids and comment on where a contractor with an extremely low price might be cutting corners and providing what may end up as a substandard job.

Involving an engineer throughout the process will cost money. Professional fees for analyzing bids and observing the construction can run 10 to 15 percent of the cost of construction. It is probably better to incur this cost than to try to skimp. "Some boards get it backwards. They call me and say they have hired a contractor and would I look at his plans to be sure the job will be okay," says Superstructures' Millman. "What this contractor is able and willing to do may not address the building's problem at all," he says, "and the right thing to do is start all over again with a professional assessment."

Another cost-saving scheme is equally unreliable. "Some property managers will call up and ask us to do a report on the condition of the roof," observes Cowley. "Then they take this report, which involved perhaps only two hours of professional time, give it to the contractor, and use it as the plan. Without the full involvement of the professional, you are probably not going to get the results you need."

Cowley recommends a task force approach, with the team including the building's engineering committee chairman, the managing agent, and the engineer and/or architect. "It should have a defined pecking order too, so that everyone knows who is in charge." Bringing in qualified, experienced professionals at the outset may be costly, but it is probably the most cost-effective solution in the long run.

Warranties, Prevention

There have been horror stories with membranes that go over older roofs. Many of them failed and buildings lost out. Engineers think that people rely too much on warranties, which are a relatively new marketing tool. Better to do the job well and spend the money wisely, they say. A warranty is an added benefit. "Every board wants a warranty," says Cowley, "but that is only one part of the total job. It's more important to have a competent contractor using materials from a well-known manufacturer. The best warranty is to have the materials installed properly."

There are two major warranty types. A "No Dollar Limit," or "NDL," warranty will provide for the full replacement of the roof if it fails any time up to the end of the warranty period. A pro-rated warranty will provide reimbursement pro-rated to the length of warranty time that remains.

The more proactive you are the better. A competent super should walk around the roof periodically. Small problems can be kept from turning into big ones with periodic recaulking and re-painting. "Twenty dollars of caulk and paint can save a lot of money," says Varone. "If the super sees a major problem while doing the regular maintenance, he can alert the board before the problem becomes a major one."

Boards also have to recognize that the roof is not meant to be left unprotected from people bringing chairs up to sunbathe or subjected to wear from people walking over it. "Rubberized pavers and special walkways should be installed so that no one walks around on the unprotected membrane," notes Rosenbaum.

The greatest impediment to a proactive program can be the nature of boards themselves. "Boards change, there is little continuity, roof issues get revisited when there is a problem," says Cowley.

Interestingly, Local Law 10/80 (which, along with Local Law 11/98, requires façade inspection every five years) may be a mixed blessing. "It's like a five-year maintenance cycle," says Cowley. It gets someone up on the roof inspecting the major components of the exterior of the building. A competent inspection will uncover roof problems as well."

Ironically, though, contractors doing façade repair can do significant damage to the roof. They move heavy equipment over the membrane and drop rubble on it. Roof work thus often ends up as a part of a major masonry project and is the last piece of the project to be completed.

In the end, the major strategy in dealing with the care and feeding of roofs is to proactively inspect, maintain, and protect them. That means annual or semi-annual inspections and controlled access. Not many co-ops do this, partly because of board turnover and because roof care is a low priority for the managing agent. But being proactive is a prescription for, if you'll pardon the pun, staying on top of the situation. After all, you don't want the roof to fall in.

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