Ceiling leak detection in Tucson, AZ

Signs of a ceiling water leak

• A yellow or brown ring with a darker edge. Several rings inside each other mean it has wet and dried more than once.
• Paint that blisters or hangs in a bubble holding water.
• A sagging or bowed section of ceiling drywall.
• Drywall tape lifting along a seam, or a line of nail heads showing rust.
• A drip from a light fixture, ceiling fan, vent register, or smoke detector.
• Mold spots in a ceiling corner, or a musty smell strongest near the ceiling.

Water runs along framing, pipes, and the top of the drywall before it soaks through, so the stain is often several feet from the source.

Common causes of a ceiling leak

• Water supply lines in the attic. Many Tucson homes have had slab lines rerouted overhead. A leak here's constant, and the meter moves.
• The air conditioner. An air handler in the attic or a ceiling closet drips condensate into a pan with a drain line. When that line clogs, the pan overflows onto the ceiling.
• An evaporative cooler. The supply line to the roof, the float valve, the pan, or the duct connection through the roof.
• An upstairs bathroom. A toilet seal, tub or shower drain, shower pan, or overflow. See bathroom leak detection.
• A water heater in the attic or an upstairs closet.
• The roof. Flashing, vent pipe boots, skylights, scuppers on flat roofs, and worn roof coating.

Roof leak or plumbing leak? Why Tucson ceiling stains are hard to read

In most places, a ceiling stain in dry weather means plumbing and a stain after rain means the roof. Tucson is less tidy than that, for 3 reasons.

First, about half the year's rain falls in the monsoon, from June 15 through September 30. That's exactly when air conditioners run longest and produce the most condensate. A stain that appears in July could be a roof leak from last night's storm or a clogged condensate drain, and both get worse in the same weeks.

Second, evaporative coolers. Many Tucson homes have one on the roof, or had one. Each is fed by a small water line that runs up from the house plumbing.

That line, the float valve, and the cooler pan can all leak onto the roof deck during the driest month of the year. Old cooler lines are sometimes left connected and under pressure after the cooler has been taken off the roof.

Third, flat and low-slope roofs are common here. Water that gets under the roof coating can travel a long way across the deck before it comes through, so the stain may be far from the entry point.

What this means for you: don't pay for a roof coating or cut open a ceiling on a guess. A meter test and pressure test show in under an hour whether the plumbing is losing water. If it isn't, and the stain only grows after storms, the answer is a roofer, and we'll say so.

How we find the source of a ceiling leak

1. Meter and pressure test. If the meter moves with everything off, a supply line or cooler line is leaking. If pressure holds on both hot and cold, supply plumbing is ruled out.
2. Map the wet area. A moisture meter and a thermal camera show the true extent of the damp ceiling and the direction the water came from.
3. Look above. Where there's attic access, we inspect directly over the stain: pipes, the air handler pan and drain, cooler ducts, vent pipes, and the underside of the roof deck. Water trails on framing lead back toward the source.
4. Test the fixtures above. In a 2-story home, the tub, shower, toilet, and sinks over the stain are run one at a time. Dye in the water confirms which one reaches the ceiling below.
5. Check the roof equipment. The cooler line, float, and pan, and the AC condensate line where it exits, are checked for leaks and blockages.
6. Report. You're told which source was confirmed, how, and which trade repairs it.

Homes with flat roofs often have no attic to enter. In that case more of the work is done from below and from the roof surface, and a small inspection opening in the ceiling may be the quickest way to confirm the source. We ask before making one.

What affects the cost of ceiling leak detection

• Attic access. A walkable attic over the stain makes for a short job. No attic, or a tight one full of ducts and blown insulation, makes for a longer one.
• What is above. A stain under an upstairs bathroom means several fixtures to test separately.
• Whether the leak is active. A leak that only shows in heavy rain or on the hottest afternoons may need to be reproduced or revisited.
• Ceiling height. Vaulted and high ceilings need more setup to scan and inspect.
• Number of stains. 2 stains in different rooms can have 2 unrelated causes.

When a ceiling leak is an emergency

A sagging or bulging ceiling is the urgent one. Wet drywall is heavy and can fall in a single sheet.

Keep everyone out from under it, move what you can, and shut off the main water valve. If the bulge is holding water and you can do it safely from the side, a small hole at the lowest point with a bucket underneath lets it drain in a controlled way.

Also act immediately if water is dripping through a light fixture, fan, or smoke detector. Turn off the breaker for that circuit and don't use the switch.

If the drip is steady and the meter is moving, close the main valve. If it only drips while the AC runs, switch the AC off at the thermostat until the drain is cleared.

How to prepare for ceiling leak detection

• Photograph the stain, outline it lightly in pencil, and date it.
• Note what was happening when it appeared or grew: rain, a shower upstairs, a hot afternoon, nothing at all.
• Do the meter test with everything off.
• Clear the attic hatch and the floor below the stain.

We identify the source and don't make repairs. Once the right trade has fixed it, the pencil outline should stop growing.

Leave the ceiling to dry fully before sealing and repainting, or the stain will come back through the paint. If it grows again after a confirmed repair, there's a second source.

For damp that's on a wall instead of overhead, see wall leak detection. Ceiling leaks are one of the most common calls we take for water leak detection in Tucson, and a good share of them turn out not to be plumbing at all.