New York's Cooperative and Condominium Community

Habitat Magazine July/August 2020 free digital issue

HABITAT

ARCHIVE ARTICLE

Getting a Good Grade

In real life, the Big Bad Wolf wouldn’t need to huff and puff to blow down the Three Little Pigs’ brick house. All he’d have to do is sit back and let the elements take their toll.

We all know the dangers of water leakage to roofs and walls, of freeze-thaw temperature cycles that cause building materials to expand and contract, and of time-and-age deterioration caused by wind, rain, salt (and other minerals), and the sun’s ultraviolet rays.

Yet often, we don’t think about the damage until a leak begins to affect the top-floor ceiling, or cracks start to spider-web across exterior walls, or, God forbid, a chunk of terra cotta cracks off and plummets to the sidewalk.

Fortunately, you don’t have to wait for the worst before taking proactive care. A range of tests – some simple and cost-free, others extensive and expensive – exists to help you pinpoint problems and head them off at the pass. And just as importantly, they may help you avoid costly repair options you don’t need.

John Brown, a board member at a 10-unit West 53rd Street co-op in Manhattan, can speak to the last. After a roof leak sprang up, he says, “there was a big debate about what part of the roof it might be coming from, whether from the bulkhead or certain pipes or up front by the parapet, and there were bubbles on parts of the roof, which is 15 years old. There was no real clarity.”

It’s the kind of mysterious, perhaps pervasive leak where many contractors would suggest an overall roof repair with all its attendant inconveniences and expense. But one company, Brown reports, suggested merely a 10-by-10-foot rubber patch at a cost of between $1,500 and $2,000. Would that quick-fix solution prove costly in the long run?

“We felt it was a gamble,” says Brown, whose board then devised a homemade test. “Since the leakage happened after some heavy rains, we tried to replicate it with a hose up on the roof.” That produced no new leaks. “So, based on what the roofer had said and where the leak was happening in the one apartment, we felt comfortable that the [10-by-10-foot] area was the most likely spot. We went with the roofer’s suggestion, and it took care of the problem. It was a question of using common sense.”

Many times, however, a board needs something more. That’s where structural testing comes in. And the tools for it can be as simple as a pair of binoculars. 

“Stand on the outside of your building on the street and look at the façade,” advises Stephen Gottlieb, head architect of the restoration firm Superstructures. You can do it yourself or have the super or a building volunteer do it. “Take your time and use binoculars. You want to look for signs of water movement or cracks.”

What specifically are you looking for? If your façade has some dirt or is slightly grayed from day-to-day wear, look for an area that’s clean, as it would be “around a downspout – what you’d call a drainpipe in non-scientific terms – which means that water instead of coming down the pipe is bypassing it and coming down the wall. The pipe may be blocked.”

Another quick and easy test Gottlieb suggests is to look for “any areas where there’s white or gray crust on the wall. The white stuff is usually shiny and sparkly, and that’s salt,” which typically exists within both bricks and mortar. When leaks or environmental changes bring water through either, it leaves a salt residue called “efflorescence” on the outside. If, on the other hand, the residue is a gray, scaly patch, that means carbonate crust is leading out of the mortar – “a phenomenon,” Gottlieb says wryly, “very similar to what you get in caves, where acid rains runs through the rock, dissolving the carbonate material like limestone or marble, which then changes when it comes out and contacts the carbon dioxide in air [creating] stalagmites and stalactites.”

Either way, salt or carbonate crust, are “often a sign of water movement through the wall, and someone should look behind it or above it.” While bricks and mortar are porous and designed to handle a certain amount of moisture, enough of it will eventually weaken them.

After the walls, check the roof. Have plastic bags somehow blown in and blocked a drain? Has someone stuck a beach umbrella through the roof, or used a chair with pointed legs? Workers often drop nails – and if someone steps on one, it can poke a hole in the rooftop material. That may seem trivial until you consider the “Grand Canyon Effect” on a smaller scale.

Other cheap, observational tests you can perform include examining the parapet, which is the small wall that surrounds and sticks up above the roof, and the coping, the top pieces of stone on a parapet wall.

“Make sure the joints are tight,” Gottlieb says. “Parapets are filled with sealant, which can be either ‘elastomeric’  – which means it stays flexible, like the white or clear silicone people typically used around tubs, or urethane, which is yellow – or ‘elastoplastic’ – which gets firm and hard, like fiberglass.”

You should also check for cracks at the building covers and above the windows, where the “flashing” – a piece of plastic or other material that channels water from inside the wall to the outside – may be broken, improperly installed or blocked, trapping water in a freeze-thaw cycle that can crack the wall and corrode any steelwork there.

All these things are akin to the physical exam a doctor gives you during a checkup before ordering any advanced tests. So when structural tests are called for in a building, what are the brick-and-mortar equivalents of x-rays and MRIs?

There are two major kinds of tests, says architect Joakim Aspegren, president of Architecture Restoration Conservation: destructive and non-destructive. The former isn’t as bad as it sounds. “A typical example,” he notes, “is a masonry probe, which involves removing one or two wythes [i.e., a continuous vertical section of masonry one unit in thickness] of brick, and is typically done to evaluate the underlying condition.

Another type involves taking a piece of masonry to measure the [water] absorption rate to determine the strength and type of cement used or to establish whether leaks are due to excessive porosity. The destructive tests are very common – the masonry probe is probably the most common test I know of.”

Non-Destructive Evaluation (NDE) tests are less common, “but I think they’re starting to be employed more often,” Aspegren says. They include infrared thermal-imagery scans, “which evaluate temperature differentials within a building envelope” – the exterior walls and other spaces, including the roof, that together comprise the building perimeter – “and can be used to locate water infiltration.”

Another NDE utilizes a linear polarization resistance (LPR) meter, which measures the presence and the rate of corrosion (in micros per year), the corresponding amount of steel loss and estimated time before the steel cracks, and whether and where there are voids present where the corrosion has eaten through. Because corrosion is dependent on temperature and humidity, calculations are more accurate if made over the course of a year.

Such advanced structural tests start at about $600 for a masonry probe plus the cost of any scaffolding that may need to be installed for non-street-level work. If the removed material needs lab analysis, add about $1,000. Infrared imaging can run between $1,000 and $3,000, with the cost depending “on the extent of the area being surveyed and the extent of the reporting level you need,” says Aspegren.

“A small extent would be a very specific area where there’s been water infiltration, and more comprehensive is where you have several apartments or the entire façade or the roof.”

Whichever advanced test you use, the ultimate goal you’re going for is to help a building engineer determine if there’s structural degradation and to give him or her data about how the building was built, “which is critical,” says Aspegren, “to the preparation of construction documents.”

The most important principle behind all these tests, from simple observation to high-tech scans, is to give yourself factual, objective data to help make informed decisions you can live with.

“Experts don’t always agree,” says Albert Spekman, treasurer of a 120-unit co-op in The Bronx’s Van Cortlandt Village neighborhood, noting that his building had lintel and roof repairs performed recently. “If some[one] says [do this], I want to know why.”

Gottlieb concurs. “If we blindly follow what an expert tells us,” he says, “we’re often going to be disappointed.” If knowledge is power, then testing is the ticket to knowledge. No huffing or puffing required.

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