---
title: "Tile Roof Underlayment Replacement Explained | Global Green Roofing"
description: "Tile roof underlayment replacement (lift and relay): the signs, how the job is done step by step, what the California code requires, and which tiles can be reused."
source: https://globalgreenroofing.com/roofing-guides/tile-roof-underlayment-replacement/
---

# Tile Roof Underlayment Replacement: How a Lift and Relay Works

By **[Global Green Roofing](https://globalgreenroofing.com/about-us/)**Published September 30, 2026Updated October 1, 2026

**Tile roof underlayment replacement, also called a lift and relay or remove and reset, means lifting the tiles off the roof, replacing the underlayment, battens and flashing beneath them, and relaying the sound tiles.** Cracked or broken tiles are replaced. The California Residential Code allows existing clay or concrete tile to be reinstalled, "except that damaged, cracked or broken slate or tile shall not be reinstalled" (Section R908.5).

It fits when the underlayment has failed across the roof while most tiles are still sound; for a single leak, a local repair may be enough (see the options table below).

## What does the underlayment do on a tile roof?

Tile roofs are not sealed. The Tile Roofing Industry Alliance (TRI), whose installation manual carries an IAPMO evaluation, describes an installed tile roof as "a highly effective water shedding assembly" whose performance depends on "the proper installation of all the tile roof components".

Some water always gets past the tiles. TRI puts it this way: "Most problems with water-shedding roof installations occur from water that migrates through improper flashing of the tile, wind-driven rain or ice damming. Because of this possibility, the underlayment is critical to the success of the roof system." The underlayment is the layer on the deck that catches that water and carries it down and off the roof. When it cracks, tears or rots, the roof leaks even though the tiles above look fine.

## Signs your tile roof needs new underlayment

-   Leaks, or ceiling and attic stains, while the tiles over them are intact
-   Underlayment that is brittle, cracked or crumbling where a tile is lifted, especially at the eaves and in valleys
-   New leaks soon after broken tiles were replaced, or leaks in several areas
-   A history of broken tiles that left the underlayment exposed to sun and rain; manufacturers warn that broken tiles let "water and UV rays" reach and damage it
-   Rotted battens or soft decking found when tiles are lifted

The only reliable way to know is to lift tiles and look. TRI "strongly recommends a qualified roofing contractor inspect the condition of the underlayment prior to conducting a tile roof repair", and says new or salvaged tiles "should not be installed over compromised underlayment regardless of the age of the roof system". A [roof inspection](https://globalgreenroofing.com/our-services/roof-inspection/) that lifts tiles in the right places answers the question before you spend money.

Planning a lift and relay? Our [tile roofing](https://globalgreenroofing.com/our-services/tile-roofing/) service covers underlayment replacement and full tile re-roofs; for a single leak or a few broken tiles, see [tile roof repair](https://globalgreenroofing.com/our-services/tile-roof-repair/).

## Local repair, lift and relay, or a new tile roof?

| Option | What happens | When it fits |
| --- | --- | --- |
| [Local repair](https://globalgreenroofing.com/our-services/tile-roof-repair/) | Tiles lifted in one area; underlayment and flashing repaired there; tiles reset | One leak, at a valley, a penetration or a wall, on underlayment that is sound elsewhere |
| Lift and relay | All tiles lifted and stacked; underlayment, battens and flashing replaced over the whole roof; sound tiles relaid | Underlayment failing across the roof; tiles mostly sound and still available to match |
| [New tile roof](https://globalgreenroofing.com/our-services/tile-roofing/) | Old tiles removed for good; new tile system installed | Tiles widely broken or discontinued with no workable match, or a change of tile style |

## How a lift and relay works, step by step

1.  **Permit and inspection of the roof.** A roof-wide underlayment replacement is a re-roof, so it is permitted and inspected (see [roofing permits in California](https://globalgreenroofing.com/roofing-guides/roofing-permit-california/)). The roof is photographed before work starts.
2.  **Lift and stack the tiles.** Tiles are removed course by course and stacked on the roof or on the ground. The code requires the roof structure to carry "the material and equipment loads that will be encountered during installation" (R908.2), so stacks are spread out.
3.  **Strip to the deck.** The old underlayment, battens and fasteners come off. The code defines a roof replacement as removal "down to the roof deck" (R908.3).
4.  **Repair the deck.** Rotted or delaminated sheathing is replaced. Tile goes over wood structural panels or solid lumber sheathing; spaced sheathing is allowed only in Seismic Design Categories A, B and C (R905.3.1).
5.  **New underlayment for the slope and wind zone.** Where wind design is not required, the code calls for a double layer on slopes from 2.5 to 4 in 12, one lapped layer at 4 in 12 and steeper, or a single layer of self-adhered membrane. Where wind design is required, it is two mechanically fastened layers, self-adhered strips over the deck joints under a full underlayment, or a single self-adhered layer, at any slope (Table R905.1.1(2)).
6.  **New flashing.** Valley metal must extend at least 11 inches each side of the valley center with a splash diverter rib, over a 36-inch strip of extra underlayment on slopes of 3 in 12 and steeper (R905.3.9). Rusted or damaged flashings, vents and similar parts "shall be replaced" (R908.5) and flashings are rebuilt to the manufacturer's instructions (R908.6).
7.  **Battens.** New battens are fastened; raised or counter-batten systems leave space under the tiles for "air flow capability and moisture drainage" (TRI manual).
8.  **Relay the tiles.** Sound tiles go back on, fastened as the code table requires for the deck and slope; cracked or broken ones are replaced with matching tiles.
9.  **Ridge, hips and eaves.** Ridge and hip tiles are reset and secured, eave closures installed, and the roof is cleaned and inspected for sign-off.

## Which underlayment goes under tile?

The 2025 California Residential Code lists the underlayment types allowed under clay and concrete tile (Table R905.1.1(1)). Where wind design is not required: ASTM D226 Type II felt, ASTM D1970 self-adhered membrane, ASTM D2626 and ASTM D6380 Class M mineral-surfaced roll roofing, and ASTM D8257 underlayment. Where wind design is required, the list narrows to ASTM D226 Type II, ASTM D1970 and ASTM D8257. Each has to carry a label showing the standard it meets.

For synthetic underlayments, TRI tells installers to "consult with the underlayment manufacturer to determine fit for use under concrete and clay tiles". Some self-adhered membranes are made for tile and rated to stay exposed for months while tiles are stacked; one manufacturer rates its tile underlayment for 180 days of exposure. Ask which product your roofer proposes, how many layers at your slope, and whether it is rated for use under tile.

## Can all of my tiles be reused?

Most sound tiles can. Tile manufacturers' own product approvals say "cracked or broken tiles must not be installed or allowed to remain on the roof", and some tiles break during lifting, so plan on replacing a share of them.

Replacements have to fit. TRI warns that replacement tiles must "properly interlock and seat" with the existing ones, and "if no tiles exist that can sufficiently interlock and seat with the existing tiles, harvesting tiles from another roof plane or a complete roof replacement may be required." On an older roof with a discontinued profile, ask how breakage will be matched before work starts.

## Protecting the new underlayment afterwards

The new underlayment only stays protected while the tiles over it are whole. TRI's walkability brief recommends stepping at the bottom 3 inches of the installed tile, the part supported by the tile beneath, with feet parallel to the ridge, and staying off hips and valleys. It adds that most manufacturers do not warrant breakage from foot traffic, and that broken tiles "should be replaced as soon as possible" to keep water and sun off the underlayment. Tell solar, HVAC and painting crews before they go up.

## What drives the cost of tile underlayment replacement

We do not publish prices, because every tile roof is priced from its own measurements. These are the factors that move the number:

-   Roof area and pitch, and how many tiles have to be lifted and stacked
-   The tile profile and how much care it needs to lift, stack and relay without breaking
-   How many tiles break or are already broken, and whether matches are still made
-   Deck repairs found once the old underlayment is off
-   The underlayment system chosen and the number of layers the slope requires
-   Valleys, walls, chimneys and skylights to flash, and the permit

## Questions to ask before you sign

-   Which underlayment, how many layers at my slope, and is it rated for use under tile?
-   Is all flashing new, including valley metal, and are vents and pipe flashings replaced?
-   How are broken tiles counted, matched and priced?
-   What happens if the deck is damaged, and how is that priced?
-   Who pulls the permit and books the inspections?

## Other questions

### How long does tile roof underlayment last?

We found no lifespan in years in the California code or the TRI installation manual. TRI notes that underlayment which has not been exposed to the elements will likely continue to shed water, which is why it is inspected rather than dated.

### Can the underlayment be replaced without removing the tiles?

No. It sits under the tiles and battens, so the tiles over any area being renewed have to be lifted. For a single leak only the tiles along the leak path are lifted.

### Does a lift and relay change how my roof looks?

Very little, if the tiles are sound and matches are found for the broken ones. The profile, color and pattern stay the same because the same tiles go back on.

### Does a tile re-roof have to meet the fire and energy rules?

It is permitted like any re-roof, so the building department applies the rules in force at your address, including the fire-rating rules in fire hazard zones and, in some climate zones, the Title 24 roofing rules. Ask the department how it treats a lift and relay before choosing materials.

Questions about your own roof? Call (323) 760-7835 or [request an estimate](https://globalgreenroofing.com/contact-us/#quote), and see our [tile roofing](https://globalgreenroofing.com/our-services/tile-roofing/) service for what the work involves.

## Sources

1.  [2025 California Residential Code, Chapter 9 (R905.1.1, R905.3, R908), via UpCodes](https://up.codes/viewer/california/ca-residential-code-2025/chapter/9/roof-assemblies)
2.  [Tile Roofing Industry Alliance, Concrete and Clay Roof Tile Installation Manual (2024 edition, revised 5/2025)](https://www.tileroofing.org/uploads/1/4/9/0/149044128/tri_alliance_2024_guide_iapmo_041725.pdf)
3.  [Tile Roofing Industry Alliance, Technical Brief 2022-001: Post Storm Event, Repairing Damaged Tiles](https://www.tileroofing.org/uploads/1/4/9/0/149044128/%E2%80%8Bpost_storm_event-considerations_for_repairing_damaged_concrete___clay_roofing_tiles.pdf)
4.  [Tile Roofing Industry Alliance, Technical Brief 2021-02: Tile Replacement Considerations](https://www.tileroofing.org/uploads/1/4/9/0/149044128/%E2%80%8Btile_replacement_considerations_for_tile_roofs.pdf)
5.  [Tile Roofing Industry Alliance, Technical Brief 2014-02: Walkability on Concrete and Clay Roof Tiles](https://www.tileroofing.org/uploads/1/4/9/0/149044128/19tri036_technical-brief-2014-02-walkability_d2.pdf)
6.  [Tile Roofing Industry Alliance, Technical Brief 2011-05: Original State of Roof Tile](https://www.tileroofing.org/uploads/1/4/9/0/149044128/19tri036_2011-05-original-state-of-tile_d2.pdf)
7.  [Eagle Roofing Products, Frequently asked questions](https://eagleroofing.com/resources/faqs/)
8.  [Polyglass, Polystick TU MAX product data sheet](https://polyglass.us/wp-content/uploads/2015/04/Polystick-TU-MAX-PDS.pdf)

Sources were read on September 30, 2026. Codes and maps change; check with your building department for the rules in force at your address.

## Have a roofer look at your roof

An on-site assessment with photos, and a written proposal before anything is decided.

## Related guides

### [Do You Need a Roofing Permit in California?](https://globalgreenroofing.com/roofing-guides/roofing-permit-california/)

Yes for a re-roof. What it checks and who pulls it.

### [What Is a Class A Fire Rated Roof, and When Does California Require One?](https://globalgreenroofing.com/roofing-guides/class-a-fire-rated-roofing/)

The rating, the roofs that qualify, and when it applies.

### [Cool Roof Requirements in California: What Title 24 Asks of a Re-Roof](https://globalgreenroofing.com/roofing-guides/cool-roof-requirements-california/)

Which re-roofs it covers, the values, and the exceptions.

Contact us

## Let's talk roofs

Tell us what is going on with your roof. We will schedule an on-site assessment and send a written proposal before anything is decided.

**Call**(323) 760-7835**Email**info@globalgreenroofing.com

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