Tile roofs in Phoenix leak because the tile isn’t what keeps the water out. The underlayment under the tile is the real waterproofing, and in Arizona heat it wears out in 15 to 25 years while the tile on top can last 40 to 50 years or more. So the most common tile roof leak in the Valley comes from a roof that looks perfect from the street, with a waterproofing layer underneath that has dried out and cracked.
How a tile roof actually works
A tile roof is two systems stacked on top of each other.
The tile sheds most of the water and shields everything underneath from the sun. It is not sealed. Water gets under tile on every roof, every storm. That is normal and expected.
The underlayment is the layer between the tile and the roof deck. Its job is to catch the water that gets under the tile and carry it down and off the roof. On older Valley homes, that layer is usually 30-pound felt. On newer or re-roofed homes, it may be a synthetic or a high-temperature self-adhered membrane.
When the underlayment is healthy, the water that gets past the tile never reaches the wood. When the underlayment fails, every storm sends water straight into the deck.
Why the underlayment fails first in Arizona
Under the tile, a Phoenix roof deck can pass 160 degrees in summer. That heat bakes the oils out of felt underlayment, year after year. It turns brittle, cracks, and eventually crumbles when touched.
Roofs that went on between the mid-1990s and late 2000s are hitting this point right now. Many of them used 30-pound felt, which sits at the short end of the lifespan range. That’s why so many tile roofs in Gilbert, Chandler, Peoria, Surprise, and across the Valley are starting to leak at the same time, with tile that still looks new.
The other places tile roofs leak
Underlayment is the big one, but it isn’t the only one.
Flashing. Metal at walls, chimneys, skylights, and valleys directs water off the roof. When it rusts, pulls away, or was installed poorly, water runs behind it.
Valleys. Where two roof slopes meet, water concentrates. Debris collects there too, and the water backs up under the tile.
Pipe boots and vents. The rubber around plumbing vents dries out and cracks in the sun. This is one of the cheapest leaks to fix.
Broken or slipped tile. Monsoon wind, a fallen branch, or someone walking the roof wrong can crack tile. A few broken tiles over healthy underlayment usually won’t leak right away. Over failing underlayment, they will.
Birdstop and weatherblock. The closures at the bottom edges and ridges keep out birds, rodents, and wind-driven rain. When they’re missing or damaged, monsoon rain blows right in.
Warning signs your tile roof’s underlayment is going
You can’t see the underlayment from the ground, but you can see what happens when it fails.
Water stains on ceilings, especially after monsoon storms.
Stains that show up in a new spot each summer.
Dark streaks or rot on the roof boards when viewed from the attic.
Daylight through the roof boards in the attic.
A roof over about 20 years old that has never had the underlayment replaced.
A roofer can lift a few tiles and show you the underlayment’s condition in a few minutes. If it cracks or crumbles when touched, the whole layer is at the end of its life.
The fix: a lift-and-relay, not new tile
Most tile roof leaks don’t need new tile. Concrete and clay tile usually has decades left. The standard fix is a lift-and-relay:
Lift the tile in sections and stack it on the roof.
Remove the old underlayment, rotted battens, and failed flashing down to the deck.
Repair any damaged decking.
Install new underlayment and new flashing at every wall, valley, and penetration.
Relay your original tile, replacing broken pieces with matched tile.
You keep the look of your roof and get brand-new waterproofing underneath. A lift-and-relay runs about $525 per square, or $10,500 to $16,000 on a typical Valley home. See the full numbers in our roof replacement cost guide.
New tile only makes sense when the existing tile is badly broken, discontinued with no matching salvage, or you want a different color or profile.
When a repair is enough
If the underlayment is still in decent shape and the leak comes from one spot, a repair is the right call:
Replacing a cracked pipe boot.
Re-flashing one wall or chimney.
Clearing and re-flashing one valley.
Replacing a handful of broken tiles.
A good roofer will tell you which one you have, and show you photos either way. More on that in how to tell if you need a new roof or just a repair.
Frequently asked questions
Why is my tile roof leaking if no tiles are broken?
Because the tile isn’t the waterproofing. The underlayment underneath has likely dried out and cracked from heat and age.
How long does tile roof underlayment last in Phoenix?
About 15 to 25 years, depending on the product. Older 30-pound felt is at the short end of that range.
Can I just replace the broken tiles?
If the underlayment is healthy, yes. If the underlayment is failing, new tiles won’t stop the leak.
Do I need all new tile?
Usually not. A lift-and-relay replaces everything under the tile and puts your original tile back.
Talk to a roofer
If your tile roof is leaking or you’re coming up on 20 years, request an inspection or call (602) 358-8458. We’ll lift a few tiles, photograph the underlayment, and tell you whether it’s a repair or a relay. More on how we do it on our tile roofing page.
Ready to talk?
Let’s look at your roof.
Enough reading — if your roof needs eyes on it, we’ll come take a look and give you a straight answer.
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