Tile Slippage and Broken Battens: Underlayment Exposure Risks and Remedies

Tile roofs suit desert homes, but heat, wind, and time test every component. Tiles shield the sun. Battens hold the tiles in place. Underlayment keeps water out. When tiles slide or battens split, the sun hits the underlayment and rain finds a path indoors. Phoenix and Tucson see long stretches of 100°+ days, sudden dust storms, and hard monsoon bursts. That mix speeds up wear and turns small tile movement into torn felt, brittle seams, and leaks. This guide breaks down why tiles slip, what underlayment exposure does to your home, and the smart fixes that lock the system back together.

Battens, tiles, and underlayment – how the trio works

Think of the roof as a team. Battens are thin wood strips fastened across the deck. Tiles hook onto those strips. Underlayment sits under the tile layer as the water barrier. Each piece plays a role:

• Battens set the spacing and hold the tile course in place.
• Tiles shed sun and rain and add weight to resist wind.
• Underlayment handles the actual waterproofing and backs up every joint.

Lose a batten or let a tile slide and the underlayment takes the hit.

Why tiles slip in Arizona

The desert punishes fasteners and wood. Common triggers:

• Thermal expansion: Concrete and clay grow and shrink each day. The movement loosens hooks and clips over years.
• Foot traffic: A few steps in the wrong spot can nudge a tile off its batten.
• Wind uplift: Summer storms lift the leading edge and pull nails from tired wood.
• Broken or rotted battens: UV, old leaks, or pests can split a strip so tiles no longer grab.
• Improper headlap or spacing: Tight spacing or shallow overlaps leave little holding power.

Once one course moves, gravity and wind keep it sliding.

What exposed underlayment really means

Underlayment dislikes direct sun. In Phoenix and Tucson the UV index runs high most of the year. Exposure leads to:

• Rapid aging: Sun dries oils in felt and weakens synthetics. The sheet gets brittle and cracks.
• Open seams: Heat softens adhesives. Laps curl and gaps open.
• Leak paths: Rain rides the tile channels, finds a split, and drops into the deck.
• Mold and ceiling stains: One puncture can wet insulation and drywall fast during a monsoon cell.

A few exposed inches can shorten the remaining life of the whole slope.

Early signs you can spot from the ground

Catch problems before they grow:

• Tiles look “stepped” or out of line, especially near eaves and valleys.
• Gaps at the butt of tiles show black or gray underlayment.
• Granules or debris collect in valleys and at dead-pan transitions.
• Daylight shows at the eaves when you peek from the attic.
• Brown rings or fresh spots appear on ceilings after a storm.

Snap photos and call a pro. Avoid walking on the roof; missteps often make more tiles slip.

The right first moves after a monsoon

Act fast and stay safe:

1. Document what you see from the ground.
2. Call a licensed roofer for a same-week visit.
3. Ask for a temporary dry-in if rain lingers in the forecast. Crews can set membrane patches around the exposed area.
4. Keep gutters and scuppers clear so water drains off quickly.

Quick cover prevents sun damage to the underlayment while you set permanent repairs.

A repair plan that lasts

A solid repair resets structure first, cosmetics second. A pro crew will:

• Map the failure: Mark slipped courses, cracked tiles, and weak strips.
• Lift and stack tiles carefully: Crews use pads and walk the overlaps, not the unsupported middle.
• Replace broken battens: Use treated or primed wood with proper thickness and straight grain.
• Upgrade fasteners: Ring-shank or screw shank nails hold better in hot, dry wood. Hot-dipped galvanized or stainless resists corrosion.
• Restore proper headlap: Set tile courses with the right overlap so wind can’t lift the leading edge.
• Reflash penetrations: Seal pipe boots and sidewalls with step flashing and kick-out at eaves.
• Seal dead-pans and valleys: Lay self-adhered membrane and set metal so water cannot pond.
• Replace broken tiles with matches: Keep the look consistent and protect the field.

That process turns a slipped patch back into a tight, code-compliant system.

Underlayment choices that beat the heat

Many older tile roofs use single-layer felt. Desert sun cooks it. Stronger options exist today:

• High-temp synthetic underlayment: Handles constant heat and resists UV longer during installation.
• Self-adhered SBS at eaves, valleys, and dead-pans: Adds a watertight seal where water slows or backs up.
• Two-ply underlayment systems: Double coverage extends service life under tile.

On roofs with widespread exposure or many weak spots, a “lift and reset” with new underlayment across a slope makes better sense than patchwork.

Prevention that pays off

Small upgrades and good habits keep tiles from moving again:

• Use battens with drainage grooves: Water dries faster and wood lasts longer.
• Add bird-stops at eaves: Stops debris and critters from nesting and pushing tiles out of place.
• Tune attic ventilation: Balanced intake and exhaust lowers deck temperature and reduces movement.
• Schedule annual roof care: Spring and post-monsoon visits clear valleys, check fasteners, and reset any early movers.
• Coordinate with other trades: Solar, HVAC, and painters should know safe paths across tile or call your roofer to help.

A short maintenance plan keeps tile roofs quiet and tight for decades.

Do you need a permit or HOA sign-off?

Many cities require a permit for large tile resets or slope-wide underlayment replacement. Most HOAs want you to match tile profile and color. A licensed roofer handles both: permit posting, inspection scheduling, and neat HOA packets with product names and photos.

The payoff: a cooler, drier, quieter home

A locked-in tile system shades the deck, sheds desert downpours, and shrugs off wind gusts. Fresh underlayment and sound battens extend the life of the roof and protect ceilings, cabinets, and floors below. Your insurance adjuster and future buyer both value a roof with documented repairs and a clean inspection record.

FAQs

1) How fast does sun ruin exposed underlayment in Phoenix or Tucson?
The desert sun dries and cracks exposed felt or synthetic underlayment in a short time. Cover exposed areas right away to protect it.

2) Can I slide a tile back into place myself?
That move risks more damage. Tiles interlock, and one wrong step can break several. Call a licensed roofer to reset and refasten the course.

3) Do slipped tiles mean I need a full reroof?
Not always. Localized slippage often needs batten repair and a reset. Widespread exposure or brittle underlayment across a slope points to a lift-and-relay.

4) What underlayment works best under tile in the desert?
High-temp synthetic with self-adhered strips at valleys and dead-pans performs well. Many homes gain years of service from a two-ply system.

5) How often should a tile roof get inspected in the Valley or Old Pueblo?
Plan on once a year and after strong monsoon storms. Crews can catch small shifts and seal them before leaks start.

Stop tile slippage fast. Call Lyons Roofing at (520) 442-1121 for expert batten repairs and underlayment protection.