Expert Leak Repairs

Long Island Roof Repair

Summary: A roof leak is a major nuisance for most commercial building owners that typically requires Suffolk County roofing repairs. Finding a leak can be frustrating or relatively simple, depending on location and weather conditions. Leak detection may go easier with these tips for locating a water leak and roof leak repair.

Ten Most Common Roof Leak Locations

Leaks are a nuisance for many commercial building owners. They can be difficult to diagnose – that is a fact. To make matters worse, different weather conditions will produce leaks in different locations, but our Suffolk County roofers have the experience and expertise needed to address any type of Long Island commercial roof repairs.

The vast majority of Long Island commercial roofing coverings operate using the principal of gravity. This can be a big help in locating a leak source. However, horizontal roof boards can trick you. Nassau County flat roofing systems and other commercial roof types have multiple seams and tend to fail and our team of experts are trained to identify these common problem areas.

Finding the source of some leaks is easy. Others will require detective work and possibly a garden hose and an inside spotter. If you don’t feel comfortable on a roof, you will have to find professional Suffolk County roofers to assist you. Sometimes this can be as hard as finding the smallest leak! Here are some tips that may help you find a leak—so you can determine if you need professional Nassau County leaky roof repair:

The Field of Shingles

If your Long Island commercial roofing is older, it is possible that the leak is within the roof field. This means the expanse of shingles, slate, shakes, whatever. If your roof is asphalt, then you can walk around with ease. Other materials such as slate, concrete tile or clay tile may not be so forgiving. You can crack roofing if you walk on it, so be careful. With regular shingles, look at the tops of the vertical knockouts. Look for missing colored granules. Look for cracks. Possibly a nail has backed itself out of the roof sheathing. Simply take your time and hunt. Better yet, contact our experienced Suffolk County roofers to make a thorough inspection for you.


A valley is a line where two roof planes intersect. Here in Long Island we use a metal flashing in the valleys. Some areas use rolled roofing. Other places simply lace the shingles together. Valleys can be big problems if you do not trim the shingles correctly. When you trim a shingle for a valley you end up with a chisel point on the end of the shingle. If a second cut is not made to make this point like an arrow point, then water can travel along the top of the shingle and find its way inside your house. The shingle wrapper tells you how to make this simple second cut.

Head Wall Flashings

Some roofs stop at a vertical wall. A metal flashing must be in place to direct water streaming down the wall away from the stopping point of the shingles. This flashing may be behind wood siding or in front of a brick wall. The flashing should extend over the shingles at least three inches. If the wall is brick or other masonry, the flashing must bend and extend one inch into a mortar joint. Tar, caulk or roofing cement should never be used in conjunction with these materials. If you see them, it is a sign that someone tried to patch a leak! Likely you need professional Nassau County leaky roof repair service.

Wall Step Flashing

Some roof leaks happen at step flashings. You find these flashings where a roof climbs alongside a vertical wall. As each row of shingles is laid, a step flashing is installed over the shingle next to the wall. Part of the flashing turns up on the wall and the other portion gets covered by the next row of shingles. Look for rust or holes in these flashings. In reality, if all is well, you will be able to see only the smallest portion of these flashings. If the flashing needs adjustment or replacement, you’ll need Brooklyn, NY, roofing repairs.


Chimneys contain four different types of flashing. All must be right or you will have a leak. Plus, the counterflashing that goes into the brick mortar joint must be right. A hairline crack above the flashing can allow vast amounts of water to run behind the flashings. Look for soldered corners of flashing that might have broken or have holes. Do not use caulk to repair these flashings! You need professional Long Island commercial roof repairs for proper handling of the situation.

Plumbing Vent Flashings

Newer vent flashings are a concern of mine. Many of these incorporate a rubber seal with an aluminum flashing. The rubber can fail in as little as 10 to 15 years. Look for cracked rubber around the plumbing pipe. The flashing should dive up and under the shingles that extend up roof from the middle of the plumbing vent. The bottom half of the flashing should be exposed and actually cover the shingles of your Suffolk County roofing.

Furnace or B-Vent Flashing

These flashings are basically identical to plumbing vent flashings. However, they sometimes have a metal storm collar. These simply fit tightly around the vertical pipe that exits the roof. If they become loose, the storm collars can cause leaks and you’ll want to schedule Queens roofing repairs.

Ice Dam Leaks

Ice Dam leaks plague people in the snow belt. These leaks can happen even if everything on your roof is just fine! Ice dams block the natural flow of water down a roof. The water begins to back up under flashings, shingles, tar paper, etc. Once water begins to flow into the house, it can drip for days. The only means of prevention is to install membranes under the roofing. The membranes won’t stop the ice but will stop water leaks if installed properly.

Wind Blown Rain Leaks

Wind driven rain can also be a major problem. Once again, you could actually have a good roof and wind will drive water up and under your roofing materials. The only lines of defense are tar paper and the ice dam membranes.

If you have metal valleys, you may want to hem the edges. This means that the hidden edges of the valley have a 180-degree bend. This creates a channel that directs wind-blown rain back to the bottom of the valley.

Roofing cement under shingles on the edges of roofs that face the wind are also a good idea. Don’t underestimate the power of a 70-mph sustained wind-driven rain. Wind blown rain leaks invariably call for professional Queens roofing repairs.


Storms are among the leading reasons we field emergency calls for Long Island commercial roof repairs. Heavy rains, lightning strikes, ice storms—these acts of nature are all too common for New Yorkers. If you know or suspect a storm has damaged your commercial roof, our Suffolk County roofers can inspect your roof and provide the ideal fix. To safeguard your roof and its underlying components, be sure to contact us for Nassau County leaky roof repair right away!

Non-Roof Leaks!

Chimney crowns can develop cracks. The inside surface of the chimney gets discolored or the plaster bubbles. You think a roof leak is the cause.

Siding can be missing above a roof. This can cause water to enter behind head flashings. Be a good gumshoe and snoop around for the leaks! If you find them, contact Cross County Roofing for our professional Long Island commercial Roof Repairs.

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