Why Tucson roofs leak in monsoon season
Many Tucson roofs go months without a drop of rain, so small problems stay hidden. Then the monsoon arrives. The National Weather Service in Tucson defines the monsoon as June 15 through September 30, and the storms that come with it can bring heavy, wind-driven rain in a short time. Water gets pushed sideways under tiles, backs up behind blocked scuppers and finds every worn piece of flashing. That's why so many leaks show up all at once in July and August.
What to do when the roof starts leaking
- Stay safe. Never go on the roof during a storm. The National Weather Service's lightning rule is simple: when thunder roars, go indoors, and stay in until 30 minutes after the last thunder.
- Catch the water. Put a bucket under the drip and move furniture and electronics away. If a ceiling is bulging with water, keep people clear of it.
- Watch for electrical risk. If water is near light fixtures or outlets, switch off that circuit at the panel if you can do so safely.
- Take photos of the stain, the drip and the time it happened. It helps find the source and is useful for any insurance claim.
- Call a roofer once the storm has passed. A temporary cover may be possible before a permanent repair.
The leak isn't always where the drip is
Water travels. It can run along underlayment, rafters or the top of a wall and show up in a ceiling several feet away from where it got in. On flat roofs, water can track a long way under the surface. That's why patching the spot directly above a stain often doesn't work.
Common sources of roof leaks in Tucson
Flashing
Where the roof meets a wall, a chimney, a skylight or a valley, metal flashing directs water away. When it lifts, rusts or was never sealed well, water gets in. Flashing is behind a large share of the leaks we see.
Cracked or slipped tiles and worn underlayment
Arizona home expert Rosie Romero notes that even one cracked tile can let monsoon water slip under and damage the underlayment, which generally lasts about eight to 20 years (source). See tile roof repair.
Flat roof coatings, ponding and scuppers
Worn foam coatings, blisters, low spots where water sits, and scuppers blocked by leaves or nests all cause flat roof leaks. See flat roof repair.
Pipe boots, vents and AC curbs
Rubber pipe boots crack in the sun, and the flashing around rooftop AC units and vents is easily damaged during service visits.
Parapets and stucco
A cracked parapet cap or a stucco crack high on a wall can let water into the wall cavity, and inside it looks exactly like a roof leak. Our own crew does both roofing and stucco, so we check both. See stucco crack repair.
How we find and fix the source
- Inside first. We look at the stain, and in the attic where there is access, to trace where the water is running.
- On the roof. We check flashings, tiles, valleys, penetrations, coatings, scuppers and parapets above and uphill of the leak.
- Repair the cause. Re-flashing, replacing tiles and underlayment in the affected area, repairing the flat roof surface, or fixing the parapet.
- Check for damage. Wet sheathing or framing gets repaired, which in the City of Tucson is structural roof work that needs a permit (City of Tucson).
When a leak means a bigger job
If leaks keep turning up in new places, the underlayment or coating may be worn out across the whole roof, and repeated patching starts costing more than a fix. Our roof replacement and roof replacement cost guides explain what's involved. If leaks have been going on a while, water may have reached framing, which our crew handles as structural repair.
Better before the storms
The best time to fix a roof leak is before it starts. A roof check in spring catches cracked tiles, worn flashing and blocked scuppers while it's dry. See our monsoon home prep checklist.
Roofing is one of the trades our own crew does in house. We find the source, explain what we found and give you a written estimate. AZ Atlas Builder Group is a licensed general contractor, AZ ROC #344537. See our main roofing page.