A Flat Roof Checklist for After a Storm in Albuquerque

Step one: the drains and scuppers

Look at each drain and scupper from the safe side. Note any debris, any standing water and any outlet that is damaged or bent.

The drains are the first item on the checklist because they decide whether the roof can shed water at all. From a secure position, look at each drain and note whether it is clear, partly blocked or full. A drain full of leaves or grit will hold water whatever the membrane is like.

The scuppers, which are the openings through the parapet or the wall, need the same look. Check that the throat is clear and the outlet is discharging clear of the wall. A scupper that dumps water down a wall face is a drainage problem and a staining problem at the same time.

Step two: the ponding

Ponding is the water that stands on the roof. Measure how long it lasts and how deep it is, and note where it sits relative to the drains.

Ponding that clears within a day after the rain has stopped is normal in the wider sense. Ponding that lasts two days or more, or that stands in the same basin every storm, is a sign the roof has settled or the drain is in the wrong place. Note the depth by eye against a known object, such as a drain bowl, and note the time it took to clear.

A deep pond on a roof can add weight and can damage the membrane. If the pond is deep or still standing after several days, call a roofer, and do not walk into the middle of it.

• Note how long the water stands
• Measure the depth against a known object
• Mark the basin on a photograph

Step three: the seams and the membrane

Check the seams from the edge, not by walking them. Look for lifting edges, cracked sealant and splits, and for bubbles that move underfoot in warm weather.

A seam that has opened will often show as a gap, a lifted edge or a line of cracked sealant along the join. From the roof edge or from a secure ladder at the parapet, you can see the lines of the seams. Note any that look lifted and photograph them.

Bubbles on a membrane should be noted without being pressed. A bubble that feels soft and moves under a footstep is a trapped pocket and needs a roofer to open it. Do not stand on a bubble to test it.

• Look for lifted seam edges and cracked sealant
• Note bubbles without pressing them
• Photograph each seam that looks open

Step four: the parapets, caps and fittings

Check the caps of the parapet walls, the counterflashing where it meets the membrane and the rooftop fittings for loose or damaged mounts.

The parapet is the wall that rises above the roof edge. Its cap should be whole and its joints closed, and the counterflashing should lie over the membrane. From the ground or a secure position, look for cracks, missing pieces and any lifted metal.

Rooftop fittings such as vents, units and skylights need a look for loose mounts, cracked seals and sealant that has dried out. Note what you see and leave the fittings alone.

• Look for cracks and missing pieces in the caps
• Check the counterflashing for lifted edges
• Note loose mounts on rooftop fittings

Step five: the inside check

Look at the top-floor ceilings and walls, especially at the edges and below the drains, for new stains, bubbling paint and damp patches.

A stain on the top-floor ceiling under a drain, a parapet or a seam is the sign that water is getting in. Mark the edge of any stain with a pencil and the date, so you can see whether it grows after the next rain.

Look also at the walls directly below the parapet. Water that runs down the inside face of a wall often shows as a line of bubbled paint or a darker band, and that is a clue to the entry point.

• Mark the edge of any new stain with a date
• Look below the parapet and drains for bubbling
• Note whether a stain grows after the next rain

What should you do with the photographs?

Keep them dated, labelled by position and stored with the roof file, so the next storm can be compared against this one.

Photographs are only useful if you can find them and read them later. Name each one with the date, the position on the roof and what it shows. Keep the files together, and make a second copy somewhere else. A set of dated photographs taken after each storm shows how the roof is changing over time, and it is the strongest record for any later claim or sale.

Take the photographs before anything is cleared, moved or repaired. A drain that has been cleared before the photograph is taken no longer shows the state it was in during the storm, and the difference may matter later.

• Name each photograph with the date and the position
• Store the files in the roof record and in a second place
• Photograph before any clearing or repair

When should a roofer be called?

When ponding is deep or lasts several days, when a seam has lifted, when a stain grows or when water is coming through the ceiling.

A roofer is the right call when the checklist shows a problem that you cannot see the cause of from the ground. Deep or long-lasting ponding, a lifted seam, a stain that grows after rain and any water coming through a ceiling should all lead to a call. The roofer walks the roof, takes the readings and writes the scope.

If you are unsure, call. A roofer can tell from a short visit whether the problem is a drain, a seam or a patch of wet insulation, and the earlier the answer, the less the repair is likely to cost.

• Deep or multi-day ponding
• A lifted seam or a bubble that moves
• A stain that grows or water in the ceiling

What belongs in a monthly walk-around?

A look from the safe side at the drains, the scuppers, the parapet caps and any puddles, with a short note of anything new since last time.

A monthly walk-around does not need to be long. From a safe position, look at the drains and the scuppers, the parapet caps and the rooftop fittings. Note any new debris, any puddle that has lasted longer than the last visit and any mark on the walls below the parapet. A short written note each month is enough to show change over time.

Keep the walk-around separate from the roofer's inspection. The walk-around is a homeowner's check for change; the roofer's inspection is the test of the roof's condition.

• Drains and scuppers from a safe position
• Puddles that last longer than before
• Notes kept with the date

When should the checklist be used?

After every large storm, after a long dry spell that follows a wet one, and at least once a year as a routine check.

The checklist is most useful after a large storm, when the drains and the seams have been tested by the weather. It is also useful after a long dry spell that follows a wet period, because a drain that held water in the wet can be seen clearly once the roof has dried. A routine check once a year, done from the ground and from inside the building, keeps the record of change running.

Use the same checklist each time, so the notes are comparable. A change from one visit to the next is the signal worth acting on, and a note that is always written in the same order makes the change easy to spot.

• After a large storm
• After a dry spell that follows a wet one
• Once a year as a routine