Why Tile Underlayment Fails Before the Tile — Quick Reference
How to read an estimate for a tile roof in West LA, and what to compare line by line.
Choosing a roofer is mostly a matter of reading estimates properly, which nobody teaches. For a tile roof in the Westside, this is what to compare and what to ignore.
What actually matters
The tile itself is usually salvageable, so the cost is mostly labour: lifting and stacking, replacing underlayment and battens, then relaying. Breakage rate during lift-off matters, and so does whether matching replacements for the broken ones are still available.
The detail that is usually left out
Read the exclusions before the total. The cheapest quote and the best quote are occasionally the same document, and the exclusions are how you tell. Bird stops, eave closures and the mortar at the ridge are what most quotes leave out. Leave them off and you have an open roof edge that invites nesting, debris and, in the fire zones, embers. Ask how it will be handled in writing, and the rest of the job tends to go the same way.
What is specific to the Westside
The marine layer decides most of what happens here. Roofs sit damp until late morning for a good part of the year, dry out in the afternoon, and do it again the next day. That cycle is gentle on the material and hard on anything organic: north-facing slopes hold moss and algae, and shaded valleys stay wet long enough to rot a felt underlayment that would have been fine two miles inland. There is a wide spread of stock, from 1920s Spanish with original clay through to flat-roofed modern rebuilds, and the two need completely different attention.
What we look at before quoting
- Underlayment age and condition, checked by lifting tile rather than guessing
- Broken, slipped and previously face-nailed tiles across the field
- Batten condition and fixing, particularly at the eave course
- Valley metal, which usually corrodes before the underlayment fails
- Ridge and hip mortar or mechanical fixing, and any movement in it
- Bird stops and eave closures, present and intact
- Flashing at walls, chimneys and every penetration through the field
Common questions
What should I check before signing?
Licence status, that the written scope matches what was discussed, and that deck repair is priced per sheet rather than left open.
Is a deposit normal?
A reasonable one is. What is not normal is a large payment before materials are on site, and California limits what can be asked for up front.
The honest summary
Judge a tile roof by its underlayment, not its tile. A roof that looks flawless from the driveway can be two winters from a ceiling repair, and the only way to know is to lift a few tiles and look. In the Westside the thing to watch is north slopes, shaded valleys and anywhere the morning damp does not clear by noon.
Free inspection, drone photography where access is difficult, and a written estimate with deck repair priced per sheet. No obligation.