Felt underlayment under a concrete or clay tile roof typically lasts about 20 to 25 years in the East Valley, while the tile on top can last for decades longer. Heat is the main reason: the felt slowly dries out, turns brittle and cracks, even when the tiles above it look perfect. If your home in Gilbert, Mesa or Chandler still has its original tile roof and was built in the early 2000s or before, the underlayment is likely near or past the end of its useful life.
Why the underlayment matters more than the tile
Tile does shed most of the rain and protects what is underneath from sun, but it is not watertight. Water runs under tiles at laps, in valleys and around vents, especially in wind-driven rain. The underlayment is the layer that actually stops that water from reaching the roof deck and your attic.
That is why a tile roof can look nearly new from the street and still leak. When the underlayment fails, the fix is not new tile. It is new underlayment, installed with the existing tile lifted off and put back. You can read more about the process in our tile roof underlayment guide.
How East Valley heat wears underlayment out
Traditional felt underlayment is a paper or fiberglass mat saturated with asphalt. The asphalt keeps it flexible and water resistant. Under a tile roof in the desert, a few things work against it year after year:
- Long, hot summers. The space between the tile and the deck gets far hotter than the outdoor air. That heat slowly drives the oils out of the asphalt, so the felt loses flexibility.
- Daily expansion and contraction. Hot days and cooler nights make the roof deck and felt move. Brittle felt eventually splits along nail lines, laps and folds.
- UV at exposed edges. Felt at the eaves, at open valleys and under broken or slipped tiles sees direct sun, and those spots usually fail first.
- Monsoon stress. Storms from June 15 to September 30 bring wind-driven rain and debris that test every weak spot at once.
Once felt cracks, it still looks like a roof layer from a distance, but water can pass through the cracks and onto the decking. Small leaks can go on for a long time before a ceiling stain shows up.
What affects how long yours lasts
The 20 to 25 year range is a general guide, not a guarantee. Several things can push a roof toward the short or long end:
- Type of underlayment. A single layer of felt is the most common original installation on East Valley homes. Double felt, synthetic underlayment and self-adhered membranes are designed to hold up better, and synthetics are generally more stable in heat and UV.
- Roof orientation and pitch. South- and west-facing slopes take the most sun. Low-slope sections drain slower and hold water against the underlayment longer.
- Attic ventilation. A hot, poorly vented attic adds heat from below. Our guide to attic heat and roof ventilation explains why that matters.
- Broken or slipped tile. Every gap in the tile exposes the felt beneath it to sun and rain, which shortens its life in that spot.
- Debris in valleys. Leaves and dust that collect in valleys and behind chimneys or walls hold moisture and slow drainage.
- Foot traffic. Solar installers, satellite techs and holiday decorating can crack tiles and tear brittle felt.
Signs your tile underlayment is wearing out
You do not need to get on the roof to watch for trouble, and you should not walk on tile. These are things you can check safely from the ground or from inside the attic:
- Your roof's age. If the house is around 20 years old or more and the roof has never been re-felted, the underlayment is the first thing to have checked.
- Felt at the eaves. From a ladder at the edge or from the ground with binoculars, look at any felt visible at the bottom edge. Dark, curled, brittle or crumbling felt is a warning sign.
- Stains in the attic. With a flashlight, look at the underside of the roof deck for dark streaks, water stains or soft spots, especially near valleys, vents and walls.
- Ceiling stains or peeling paint inside the house, particularly after winter rain or a monsoon storm.
- Broken, slipped or missing tiles you can see from the yard. They do not always mean the underlayment has failed, but they expose it.
Our safe DIY roof checks guide walks through what you can look at without climbing onto the roof.
Repair, re-felt or replace?
When a roofer finds worn underlayment, there are usually three paths:
- Spot repair. If the damage is limited to one area, such as a valley or around a vent, that section's tile can be lifted, the underlayment and flashing replaced, and the tile reset. This makes sense when the rest of the felt is still in good shape.
- Re-felt (lift and relay). If the felt is brittle across the roof but most tiles are sound, the tile is removed and stacked, new underlayment and flashings go on, and the same tile is reinstalled with replacements for any broken pieces.
- Full replacement. If many tiles are cracked or you want a different look, new tile and new underlayment go on together.
A roof inspection is the best way to know which one fits your roof. For typical price ranges, see our roofing cost guide, and for more about our repair work, visit repairs and maintenance.
Why fall and winter are good times to plan
Winter rain in the East Valley tends to be slower and steadier than monsoon downpours, and that kind of rain often finds failing underlayment. Having your roof looked at in the cooler months lets you plan a repair or re-felt on your schedule instead of after a leak. If your HOA needs to approve the work, it also leaves time for that before monsoon season.
Questions homeowners ask
Do I need new tile if my underlayment is worn out?
Usually not. Concrete and clay tile often outlast the underlayment by many years. In a re-felt, your existing tiles are removed, new underlayment goes on, and the same tiles are reinstalled, with any broken ones replaced. Learn more on our tile roofs page.
How long will new underlayment last?
That depends on the material and how the roof is maintained. Synthetic and double-layer options are designed to outlast a single layer of traditional felt. Keeping tiles intact and valleys clear helps any underlayment last longer.
Can I tell if my underlayment is bad without getting on the roof?
You can spot warning signs from the ground and attic, like brittle felt at the eaves or stains on the roof deck. Confirming the condition across the roof takes a roofer who knows how to move on tile without breaking it.
My roof isn't leaking. Should I still have it checked?
If it is 20 years old or more with original underlayment, yes. Felt can be cracked for some time before water shows up inside, and catching it early can keep a small repair from becoming a bigger one. Our FAQ covers more common questions.
Integrity Roofing has been family owned since 1993 and works on tile roofs across Gilbert, Mesa, Chandler and the rest of the East Valley (Arizona ROC #096629). If your roof is getting close to the 20-year mark or you have noticed any of the signs above, call us at 602-548-3770, Monday to Friday, 7 am to 5 pm, to schedule an inspection. If we don't answer, leave a message and we'll return your call within 24 hours.
