Practice 04 — Tile Underlayment

Your roof tiles may
last for decades. The
waterproofing beneath
them often does not.

Tile roof underlayment replacement — the lift-and-reset — restores the waterproofing under a tile roof that still looks fine from the street. It is the most common work we do in Phoenix.

Also known as Tile lift-and-reset
Tile re-underlayment
Workmanship warranty 5 years minimum
Barrel tile roof in Phoenix with Piestewa Peak behind it
01Phoenix, Arizona — the tile survives the desert. The layer beneath it is what wears out.
Index 01 — The system

Your roof tiles aren't the whole roof.

Concrete and clay tiles are extremely durable, but they are not the roof's primary waterproof barrier. Wind-driven rain can pass between and beneath the tiles. The underlayment installed over the roof deck is what helps prevent that water from entering your home.

Over time, Arizona's intense heat, temperature changes, monsoon storms, and normal material aging can cause the underlayment to dry out, crack, shrink, or separate. The tiles may still look perfectly good even though the protective layer underneath is beginning to fail.

The Tile Roofing Industry Alliance's installation standards emphasize the importance of properly installed underlayment, flashing, fasteners, penetrations, and drainage details as parts of the complete tile roof system. Tile Roofing Industry Alliance installation manual

Index 02 — Service life

How long does tile roof underlayment last?

The lifespan depends on the material, installation quality, ventilation, roof design, maintenance, and exposure to heat.

Underlayment typeGeneral service-life range
Traditional asphalt-saturated feltApproximately 15–25 years
Higher-grade or double-layer felt systemsApproximately 20–30 years
Synthetic underlaymentOften 25–40+ years
Self-adhered modified-bitumen membraneOften 30–40+ years

These are general planning ranges—not guarantees. Arizona heat can accelerate aging, and workmanship problems can cause even relatively new underlayment to fail prematurely.

A professional inspection is usually recommended once a tile roof reaches approximately 15–20 years old, especially if its maintenance or reroofing history is unknown.

Index 03 — Failure modes

Why tile roof underlayment fails

01

Extreme Arizona Heat

Roof temperatures can become significantly hotter than the surrounding air. Years of heat exposure can dry out asphalt-based underlayment, causing it to become brittle, crack, and lose flexibility.

02

Expansion and Contraction

Roofing materials repeatedly expand during hot days and contract as temperatures fall. That movement places stress on the underlayment, flashing, seams, fasteners, and roof penetrations.

03

Poor Initial Installation

Underlayment may fail early when it is improperly lapped, inadequately fastened, damaged during tile installation, or installed without correctly integrating flashing and penetrations.

04

Deteriorated Flashing

Leaks frequently develop around valleys, walls, chimneys, skylights, plumbing vents, and HVAC penetrations. Failed flashing can allow water beneath the tile system even when the field tiles remain intact.

05

Broken or Slipped Tiles

Cracked, missing, or displaced tiles expose the underlayment to sunlight and direct weather. Synthetic underlayments can offer improved durability compared with conventional felt, but exposure limits and installation requirements still depend on the specific product.

06

Monsoon Winds and Wind-Driven Rain

Arizona storms can push water beneath tiles and into vulnerable laps, valleys, penetrations, and flashing transitions. Wind can also loosen or shift tiles, leaving the underlayment exposed.

07

Foot Traffic

Walking on a tile roof can crack tiles and damage the material underneath. Damage is especially likely when service technicians or inexperienced contractors do not understand how to safely access tile roofing.

08

Debris and Poor Drainage

Leaves, bird nests, dirt, and other debris can obstruct valleys and drainage paths. Water may then back up beneath the tile and place additional stress on the underlayment.

09

Animal and Pest Damage

Birds, rodents, and insects may enter beneath loose tiles or damaged bird stops. Their activity can disturb the tiles, underlayment, and flashing.

Underlayment exposure limits and installation requirements vary by product — see GAF underlayment technical information.

Index 04 — Warning signs

Warning signs of underlayment failure

Contact a roofing professional if you notice:

A leak does not always appear directly below the failure point. Water can travel along the underlayment, roof deck, or framing before becoming visible inside the home.

  • Ceiling stains or interior water damage
  • Leaks during monsoon storms
  • Water marks in the attic
  • Musty odors or signs of moisture
  • Broken, missing, or slipped tiles
  • Debris collecting in roof valleys
  • Cracked or deteriorated flashing
  • Previous roof repairs that continue to leak
  • An original tile roof approaching 20 years old
  • Multiple leaks occurring in different areas
Index 05 — Reuse

Can the existing roof tiles be reused? Often, yes.

During a tile roof underlayment replacement, reusable tiles can be carefully removed and stacked. The deteriorated underlayment and old flashing are removed, damaged decking is repaired as necessary, and a new waterproofing system is installed. The original tiles are then reset, with broken or unusable pieces replaced as needed.

This process is commonly known as a tile lift-and-reset or tile re-underlayment.

Whether tiles can be reused depends on their condition, availability, fastening method, brittleness, and the percentage damaged during removal.

Index 06 — Scope

Repair or replace the underlayment?

A localized repair

A localized repair may be appropriate when the damage is limited to one identifiable area, such as a broken tile, plumbing penetration, or small flashing defect.

A complete lift-and-reset

A complete lift-and-reset may be the better long-term solution when:

  • The underlayment is brittle or deteriorated throughout the roof
  • Leaks are occurring in multiple locations
  • Previous repairs have not solved the problem
  • The roof is near or beyond its expected service life
  • Large sections of flashing are failing
  • Repair costs are beginning to accumulate

Patching one area cannot stop deterioration occurring throughout an aging underlayment system.

Index 07 — Method

What happens during underlayment replacement

  1. The property and surrounding landscaping are protected.
  2. Existing tiles are carefully removed and staged.
  3. Old underlayment, battens, and deteriorated flashing are removed.
  4. The roof deck is inspected for moisture or structural damage.
  5. Necessary decking repairs are completed.
  6. New underlayment and flashing components are installed.
  7. Valleys, walls, penetrations, and drainage transitions are properly detailed.
  8. Reusable tiles are reset and replacement tiles are installed where needed.
  9. The roof and property receive a final inspection and cleanup.
5 year
Workmanship warranty

Every project we complete carries a minimum five-year workmanship warranty, separate from the manufacturer's material warranty on the underlayment system itself. If a detail we installed is the reason water gets in, we come back and correct it.

Schedule a tile roof inspection

If your tile roof is
near twenty, the felt
is the question.

If your tile roof is approaching 20 years old—or you have noticed leaks, stains, slipped tiles, or recurring repairs—it may be time to inspect the underlayment. A professional inspection can help determine whether the problem requires a targeted repair or a complete tile lift-and-reset.

(412) 713-8369 — call for a tile roof inspection.