Commercial Roofing in Concourse, Bronx, NY

Concourse buildings look alike from the street and fail differently on the roof. The Tudor Revival and Art Deco apartment houses along the boulevard, built under the 1901 Tenement House Act, put a low-slope roof behind a decorative parapet, and the decoration is what leaks: a cornice joint, a loose cap stone, a counterflashing that no longer meets the wall. A manager in Bronx, NY should check those details before blaming the field membrane. Then check the drains and the bulkhead.

Five and six story houses on the boulevard

Concourse is rich in five and six story multifamily buildings, Tudor Revival to Art Deco, put up under the 1901 Tenement House Act. The street changes character near the courthouse and the stadium. The Bronx Hall of Justice dates to 2007, the Bronx Courthouse also serves as Bronx Borough Hall, the new Yankee Stadium and the Bronx Terminal Market both opened in 2009, and Major Deegan Expressway (I-87) exits serve the neighborhood.

That gives owners two kinds of roof work: the apartment house with a flat roof behind a styled parapet and the commercial or civic building with a larger deck, rooftop equipment and a public face. Both want a written condition report before anyone writes a scope, because decoration and drainage have to be solved together.

The historic district and what it touches

In 2011 the Landmarks Preservation Commission designated a large part of the neighborhood the Grand Concourse Historic District, and exterior work such as roof replacement can fall under that designation. For an owner, that means the first question on a roof job is whether the work is visible from the street or changes the parapet, cornice or any rooftop structure. A repair that stays behind the parapet and uses the same materials is a different filing from a new coping profile.

We photograph the existing parapet and cornice, mark what the scope would change and give the owner what the filing needs. Replacement of a flat membrane that is invisible from the street is a different process than rebuilding a parapet. Confirm the pathway with the Commission before ordering material, since a delay in paperwork costs less than rework on the roof.

Cap stones, cornices and counterflashing

A parapet wall on a boulevard apartment house is brick or terra cotta capped with stone, and the cap stones sit on mortar that opens with freeze and thaw. Once the joint opens, water gets into the wall. Counterflashing tucked into a reglet may have pulled out, so the roof edge can look intact while water travels behind it. We probe each joint, tap each stone and photograph the results.

Typical fixes are repointing, resetting loose stones, replacing counterflashing and sealing the cap. They fit the definition of flashing failure repair, and they are the items that prevent a repeat leak. In a landmark district we match the existing stone and mortar color so the street view does not change.

The flat roof behind the parapet

An older Concourse roof may be built-up membrane with a gravel or coating surface, and years of patching can leave a stack of layers. We find wet sections with an infrared scan after sunset, confirm with cores and cut the wet part out. If the rest is dry, a coating or a fully adhered recover over cover board is available, and cover board and insulation choices decide how long it lasts.

Drains are the other half. Many of these roofs have one or two outlets, so a clogged strainer holds the whole roof in a pond. We clear and photograph every strainer, and where a scupper serves as overflow, we check it for debris and height. A roof that ponds two days after ordinary rain needs slope correction, a new outlet or both.

For the membrane itself, the usual choices on a boulevard apartment house are a new built-up roof that matches the existing build-up, a modified bitumen system or a fully adhered single ply. The deciding factors are the deck, the weight the structure can add, fire-safety rules for torch work and how the new roof meets the parapet. Where the existing parapet flashing is sound, new membrane is turned up and terminated under the counterflashing. Where it is not, the wall detail is rebuilt first, since a new membrane against a failed wall detail only moves the leak.

Commercial and civic roofs near the stadium and terminal

Gateway Center spreads 17 acres of retail across the Bronx Terminal Market site beside the Major Deegan Expressway and includes a six-level, 2,600-car garage. Retail and civic buildings in this part of the neighborhood tend to carry equipment, wide decks and drains that serve large areas, and floor area is not the same as roof area, so each roof is measured on its own.

Streets around the stadium and the terminal can be congested, so deliveries and crane lifts are scheduled around peak traffic, and the hoist location is chosen before the permit is filed. Shopping center roofs and government buildings share a need for walk pads, scheduled strainer cleaning and a roof register, so crews know what has been repaired.

Storms, snow and the work window

Ida's record hour of 3.15 inches in September 2021 is a test that a roof holding water in ordinary rain cannot pass. The Central Park station totals about 29.8 inches of snow a year and has touched -15 F, so parapet joints and flashings are stressed by freeze and thaw every winter. We plan membrane work for late spring through early fall, and Morrisania and Highbridge neighbors follow the same window.

The Department of Buildings provides the 2022 NYC Construction Codes. Filings go there.

Commercial Roofing Questions

Our Concourse building has a leak in the top-floor corridor, but the roof looks fine. Where do we look?

Look at the parapet before the field. Water that gets behind a cap stone or past counterflashing runs down the inside of the wall and appears in a corridor or ceiling corner far from the opening. We walk the parapet joint by joint, probe the mortar and check the counterflashing, then trace the stain upward.

Does a roof replacement in the Grand Concourse Historic District need approval?

It can. The district designation can affect exterior work such as roof replacement, and the deciding point is whether the work is visible or changes the parapet, cornice or a rooftop structure. We photograph the existing condition and prepare the scope so the owner can confirm the path with the Commission before ordering material.

How should an owner handle a flat roof that ponds after every storm?

Find out why before choosing a fix. A clogged strainer is a cleaning job. A low spot or a sagging deck needs tapered insulation or a new outlet. We time the pond, clear the drain and survey the slope, then write up the repair with a price for each option.

Can the building stay occupied during a recover?

Yes. Our approach to occupied building reroofing works in sections, dries in each before opening the next, and keeps the stair and egress routes clear. Hoisting and staging are set for hours the superintendent approves, and tenants receive notice of the loud days.

What records help before a roof walk?

Bring the roof age, the last repair invoice, any earlier approvals and the last tenant complaint, plus photos of the worst stain. For a landmark-district building, add the date and scope of the last exterior approval, because the Commission may have asked for specific materials. A drawing of where the roof hatch and bulkhead sit helps plan access.