A Roof Check to Finish Before the Next Heavy Rain in San Diego

Why check before the rain rather than after it?

A check before the rain finds a fault while it is small and while the weather allows a repair. A check after a storm finds the same fault with water already in the building.

The time between the first sign of a fault and the next heavy rain is the time the owner has to act. A blocked outlet can be cleared in minutes; a lifted flashing can be re-sealed in a dry afternoon. The same faults after the rain may need a tarp, a drying plan and a longer repair.

The pre-storm check is also a record. The photographs taken before the rain show the roof's condition at the start of the season, so any change after the storm is easier to see.

What can a homeowner check from the ground?

From the ground, the outlets, the downspouts and the gutter line can be checked. The flashing at each vent and chimney, and any valley visible from the edge, can also be seen without climbing.

Clear the outlets of leaves and grit, and check that each downspout discharges clear of the foundation. A splash block or a short extension that carries the water away from the wall is often the simplest fix.

Look for sagging gutter runs, bent sections and brackets that have pulled away. A run that holds a pool at a dip is a fault that a heavy rain will show, so note it and call for a repair before the storm.

• Clear every outlet and check the downspout discharge
• Look for sags and holes in the gutter line
• Check that the splash block or extension carries water away from the wall
• Look for lifted metal at the vents and chimney from the ground

What belongs in the attic check?

The attic check looks for wet or stained wood, rust on nails and the dark line of a valley. It is done from the access hatch on a dry day, with a torch, and nothing is moved or cut.

Look at the sheathing above each valley and vent, and at the rafters near the eaves. A board that is darker than the rest, a patch with a white bloom or a nail with rust around its head is a sign that water has been reaching the structure.

Note what is seen and photograph it from the same spot. A new mark after the next rain is then easy to identify, and it tells the owner where the water came in.

When should a homeowner call a technician?

Call when a fault is found that water could reach, such as a lifted flashing, a cracked valley or a stain in the attic. Call also when the owner is not sure what a mark means.

A technician reads the fault and decides whether it needs a repair before the next storm or a temporary cover. A fault that is not reached before the rain may need a tarp fixed to the structure, and the crew can fit it the same day if one is free.

The owner should not climb onto the roof to do the work alone. A steep roof, a wet covering and a ladder on uneven ground are the commonest causes of a serious fall, and the work is best left to a crew with the right equipment.

What should be ready for the storm itself?

Have the outlet cleared, the number of the technician written down, a container and a tarp's fixing ready, and the valuables moved away from the ceilings that are most at risk.

A container for the drip in the room below the most likely leak is a simple precaution. Move furniture and valuables away from the ceiling stain, and switch off the light at the wall if the stain is near a fitting.

After the rain, walk the outside and the ceilings again, and record anything new. The record is the start of the next check, and the owner can see from the file which faults the storm tested.

How do the faults differ between a light rain and a heavy day?

A light rain tests the surface and the outlets, and a heavy day tests the flow and the joints. A fault that a light rain does not reach can be opened by a heavy flow, so the pre-storm check looks for the faults that a heavy day would find.

In a light rain, water runs off the covering and into the gutter with little pressure. The faults it finds are the ones at the surface: a missing tab, a bent gutter or a blocked outlet. In a heavy day the flow is much larger, and water is driven into any joint that is not sealed or lapped correctly.

That is why the flashing at a valley or a vent is checked for lift before the rain, not after. A lifted piece that was dry in a light rain can take the full flow of a heavy one and send water into the attic.

What should a homeowner look at on a flat section?

A flat section is checked for standing water, for the drains and their outlets and for the seams at the edge. A pool that stays after the last rain will hold more water in a heavy storm, and the membrane will be under greater load.

Walk the flat area from the access, if it is safe, and look for a pool that has not dried. Note its position, its depth and whether a drain sits beside it. A drain that is blocked by leaves or grit is cleared from the surface, without climbing onto the membrane.

Look at the parapet and the edge for loose caps and for a seam that has lifted. A technician can then decide whether the seam needs a patch before the storm or a larger repair after it.

What if a fault is found and the rain is close?

If a fault is found and the rain is close, the owner covers what can be covered safely and calls for the earliest visit. The cover is a stopgap, and the repair follows once the weather allows.

A tarp fixed to the structure by a crew is the usual cover for an open roof. A surface sealant on a clean, dry joint within reach from the ground is a stopgap for a small joint, and it does not repair a lifted flashing. Neither should be done on a steep roof by the owner.

The owner writes down the fault, its position and the time it was found, and photographs it. The record is useful to the technician and, if the storm causes damage, to any later claim.

How is the check kept as a routine across the seasons?

The check is kept as a routine by using the same list each time, from the same spots, and by keeping the notes in one file. A routine is more reliable than a memory, and it lets the owner see the change from one storm to the next.

A list kept with the file names each part of the roof in the order it is checked: outlets, gutter run, valleys, vents and chimney, flat section, attic. Each check is dated and the findings are written beside the list, so the next check can start from the last one.

The file also records what was done. A repaired joint, a cleared drain or an extended outlet is written in, with the date, so the owner knows which faults have been dealt with and which are still open. That record is the most useful part of the file in a year with several storms.