What a Nor'easter Leaves on a Hempstead Roof

Why does a nor'easter damage a roof differently from other storms?

Because it brings long hours of wind and rain from a changing direction, which pushes water under the covering and lifts edges that were sealed for calmer weather.

A nor'easter is a storm that brings wind and rain for long hours, and the wind can change direction as the storm moves. That pushes water up under shingles and into joints that were sealed for calmer conditions. A roof can hold up to one short burst of wind and fail under a long, sustained storm, because the water has time to work its way in.

Nor'easters are one of the named drivers of roof damage on Long Island, with hurricane remnants and wind. Their damage is often found after the storm has passed, which is why the check should follow the storm rather than wait for the first leak.

What can be seen from the ground after a storm?

Shingles on the ground, a gutter that has pulled away, a downspout that is bent or a vent cap that has been knocked off. Those are signs of damage on the roof above.

After a storm, walk the perimeter and look at the ground near the house. A shingle, a piece of ridge cap or a bent vent cap on the ground shows that the wind has taken material from the roof. A gutter hanging from the fascia or a downspout that is loose shows the water and the wind have moved the edge.

Look at the roof edge from the ground, too. A line of missing or lifted shingles at the eave, or a curled edge at the rake, is a sign to call. Photograph each one from a safe distance, with the date.

• Shingles or ridge pieces on the ground
• Gutters hanging, sagging or pulled from the fascia
• A bent or loose downspout
• A vent cap or flashing piece missing or knocked off

Which signs need a call the same day?

Any water coming into the house, a ceiling that is wet or sagging, and a large opening in the roof that exposes the decking. Those signs need a tarp or a temporary cover the same day.

A stain that grows, a drip in a room, a wet ceiling or a bulge in the ceiling are signs that water is coming in now. Those need a call the same day, and a homeowner should move valuables and protect the floor while waiting for the crew.

A large open area of the roof, where the decking or the underlayment is exposed, also needs a cover before the next rain. The homeowner should not climb onto the roof to fit one, and should call the roofer for a tarp.

Which signs can wait for the inspection?

Small lifted shingles that are not leaking, gutters that have sagged without pulling away and a loose vent cap with no water entry. Those can be recorded and inspected on a scheduled visit.

A single lifted shingle that is not letting water in can usually wait for the inspection, provided the roof is checked soon. The same is true of a gutter that sags but has not come away, and of a vent cap that is loose without any sign of water.

The waiting period should be short, and the homeowner should watch the signs and photograph them. If any of them changes, or water appears after the next rain, the call should be made at once.

Why does the flashing matter so much after a nor'easter?

Because the flashing at chimneys, vents and skylights is where the wind-driven rain finds a gap first. A joint that was sealed for calm weather can open in a storm and leak a day or two later.

Flashing is the metal that seals each joint between the roof and anything that comes through it. Wind-driven rain pushes water into the gaps around the flashing, and the sealant dries and cracks over time. A storm can open the joint without leaving any visible sign on the surface.

A roofer checks each joint after a nor'easter and tests the suspect ones with water from a safe position. The test shows the gap before the next storm does.

What should be photographed and kept?

Every sign, with a scale object and the date. The photographs are the homeowner's evidence for the insurer and the roofer, and they should be kept before any cleanup or repair.

The New York DFS guidance from the Sandy response advises homeowners to take photographs or video of the damage before cleaning up, and to make only the repairs needed to stop further damage until the insurer inspects. That advice still applies after a nor'easter.

Keep the photographs in their original form with the date. A file of photographs, the storm date and the notes is the start of the record for the house.

• Photograph each sign from the ground and, if safe, from a window
• Include a scale object and keep the date
• Note the time the sign was first seen
• Keep the photographs before any cleanup

What to do in the week after a nor'easter

Check the ceilings and the attic after each rain, call for an inspection if any sign is new, and keep the record up to date. The first week is when small damage is still small.

In the week after a nor'easter, check the ceilings and the walls near the outside for new stains after each rain. Check the attic on a dry day for damp wood or insulation. Any new sign is reported with the date, the place and a photograph.

A roofer can inspect the roof in the week after the storm, and the inspection report is the record the homeowner keeps for the house and for any later claim.

How wind and rain find the roof edge

A nor'easter's wind lifts the edges of the covering and drives rain under them. The eave and the rake take the most, and the first signs usually appear there.

The wind of a nor'easter strikes the house and runs up the roof, and at the edges it creates the strongest uplift. The shingles at the eave and the rake are lifted first, and the rain that follows is pushed under the lifted edge and into the joints. A shingle can be lifted without being torn off, which means the damage is easy to miss from the ground.

The roofer checks the seal of each shingle near the edges by gently lifting it. A shingle that stays down is sound, and one that lifts and does not return has lost its seal. Those are the places the next storm will tear first.

What happens to the gutters and downspouts?

Gutters pull from the fascia under the weight of wind-driven water, and downspouts come loose at their outlets. Both leave water running against the wall and the foundation.

A gutter that holds water in a strong storm can be pulled from its hangers, and a section can sag or twist. Once it is loose, the water runs over the front edge onto the fascia and the wall. A downspout that comes away at the outlet sends the water down the wall rather than away from the house, and that water can reach the foundation.

The roofer checks the gutters and downspouts after a nor'easter, and the note records any section that needs refitting. A gutter guard can reduce the debris that blocks the flow, and the note says whether one is recommended.

What a homeowner should record after the storm

The date the storm arrived and left, the wind and rain as reported locally, the time each sign was first seen and the place it was seen. Those facts are the timeline the insurer and the roofer will ask for.

Keep a short note of the storm: when it started, when it passed and what the weather was like during it. Add the time each sign was noticed and the place. A note made on the day is more reliable than one made a week later, when the details have blurred.

Keep the note with the photographs. Together they form the first part of the file for the house, and they are useful whether the damage turns out to need a repair or a claim.

Why the signs can appear days after the storm

Water that gets under a shingle or past a joint can take days to reach the ceiling, so a stain may appear well after the storm has passed. The check should continue for a week, not stop when the wind drops.

Water moves slowly through the roof structure. It runs along the underlay, down the decking and along the rafters before it reaches the ceiling. A homeowner who looks only on the day of the storm can miss the first sign. A short daily look at the ceilings and the attic for a week after the storm catches the signs as they appear.