Clay tile roof installation follows a fixed sequence: verify the structure can carry the load, deck and dry-in the roof, lay underlayment, set battens (or plan a direct-nail layout), install field tiles course by course from the eave up, then finish hips, ridges, and flashing. A clay tile assembly weighs roughly 9 to 12 pounds per square foot installed, four to five times an asphalt shingle roof, so the load check comes before anything else. Most of the failures on these roofs trace back to the underlayment and the flashing, not the tile, which is why the dry-in details below matter more than the tile-setting itself.
This guide covers the installation process only. For pricing, lifespan, and whether clay is the right material for your house, see our companion guide on clay tile roof cost and lifespan.
Can your roof structure carry a clay tile roof?
Before any tile goes up, the framing has to be rated for the dead load. Installed clay tile runs about 9 to 12 pounds per square foot for standard profiles, and heavy barrel or mission profiles can reach 12 to 15 or more. A framing system built for asphalt shingles (roughly 2 to 3 psf) usually cannot carry that without reinforcement. On new construction, engineered trusses or rafters are specified for the tile load from the start.
For a re-roof from a lighter material to clay, a structural engineer should evaluate rafter or truss size, spacing, and span before you commit. Reinforcement can mean sistering rafters, adding purlins, or upgrading trusses. Skipping this step is the single most expensive mistake on a tile conversion, because the fix after tiles are loaded is far worse than the fix before.
| Material | Approx. installed weight (psf) | Weight per roofing square (100 sq ft) |
|---|---|---|
| Asphalt shingles | 2 to 3 | 200 to 300 lb |
| Standard clay tile | 9 to 12 | 900 to 1,200 lb |
| Heavy clay (barrel/mission) | 12 to 15+ | 1,200 to 1,500+ lb |
| Concrete tile | 9 to 11 | 900 to 1,100 lb |
What roof slope does clay tile require?
Clay and concrete roof tile installs on slopes of 2.5:12 (a 21 percent slope) or greater under IRC Section R905.3. Below that pitch, tile is not a code-approved covering because water moves too slowly to shed reliably through the laps. Between 2.5:12 and 4:12, the underlayment does more of the waterproofing work, so codes generally call for a doubled underlayment layer on these lower slopes.
Slope also drives the fastening and batten decisions. Steeper roofs need more anchoring to keep tiles from sliding, and lower slopes need extra underlayment protection because the tile alone is not the water barrier. Confirm your exact pitch first, because it sets the rules for every step that follows.
Step-by-step clay tile roof installation process
The core installation runs in a set order from deck to ridge. Each step below is a distinct stage a crew completes and inspects before moving on. Skipping ahead, especially past the dry-in, is where leaks start.
- Prepare and inspect the deck. Install or verify solid sheathing (typically minimum 15/32-inch plywood or 7/16-inch OSB), replace any rotted decking, and sweep the surface clean. The deck must be dry and structurally sound before underlayment goes down.
- Install drip edge and dry-in. Set metal drip edge at eaves and rakes. In ice-prone climates, an ice-and-water membrane runs along the eaves per code.
- Lay the underlayment. Roll underlayment from the eave upward, overlapping courses (commonly 2 to 4 inches horizontal, 6 inches at end laps), and fasten to the deck. Double the layer on slopes between 2.5:12 and 4:12.
- Install flashing at penetrations and walls. Set valley metal, headwall and sidewall flashing, and pipe flashings integrated into the underlayment before tile.
- Snap layout lines and set battens (if used). Chalk horizontal courses to the tile’s headlap, then nail 1-inch by 2-inch nominal battens perpendicular to rafters, or plan the direct-nail layout.
- Install field tiles course by course. Start at the eave with the first course, work up and across, overlapping each tile per the manufacturer’s exposure, and fasten through the nail holes without over-driving.
- Finish hips and ridges. Set hip and ridge tiles over a nailer or mortar/foam closure, lapping toward prevailing weather, with the last tiles mechanically fastened.
- Detail edges and clean up. Cut and fit rake, valley, and penetration tiles, seal cut edges as specified, and inspect every fastener and lap.
Clay tile roof underlayment: what to use and when to double it
Underlayment is the real waterproofing layer on a clay tile roof, because tile sheds most water but is not watertight on its own. Water that gets under a tile in wind-driven rain runs on the underlayment to the eave. For that reason, tile roofs are only as durable as the membrane beneath them, and the underlayment usually fails decades before the tile does.
Standard practice uses a single layer of 30-pound felt or a high-temperature synthetic or self-adhered membrane on slopes of 4:12 and steeper, and a doubled layer on 2.5:12 to 4:12. Self-adhered (peel-and-stick) membranes are common in high-wind and high-heat regions because they seal around fasteners. Because underlayment outlives one tile lifespan rarely, many owners re-lay the same tiles over fresh underlayment mid-life. Compare membrane options in our guide to roof underlayment types and when each is required.
Battens vs direct-nail: how tiles attach to the roof
Tiles attach one of two ways: nailed directly through the tile into the deck (direct-nail), or hung on and nailed to horizontal wood battens. Battens are 1-inch by 2-inch nominal wood strips run across the roof at the tile’s headlap spacing. The choice depends mainly on slope, climate, and tile profile, and code sets the outer limits.
Battens are generally required on slopes steeper than 7:12, where they give the tile a positive anchor and stop it sliding. Direct-nail is common on moderate slopes in dry climates. Counter-battens (vertical strips under the horizontal battens) create a drainage and ventilation gap that helps the underlayment dry, which matters in wet or freeze-thaw climates. Fastening counts scale with exposure: tiles under 9 psf need at least one fastener each, and snow areas require at least two fasteners per tile.
| Factor | Direct-nail | Battens |
|---|---|---|
| Typical slope | 2.5:12 to 7:12 | Above 7:12 (often required) |
| Underlayment drainage | Water sits closer to deck | Gap aids drying (with counter-battens) |
| Fastener path | Through tile into deck | Tile nose hooks/nails to batten |
| Best for | Dry climates, moderate pitch | Steep pitch, wet/freeze-thaw climates |
| Underlayment penetrations | More holes in the membrane | Fewer holes in the field membrane |
Installing field tiles, courses, and exposure
Field tiles install from the eave upward, course by course, each overlapping the one below to shed water. The first (starter) course sets the exposure for the whole roof, so it is snapped to a chalk line and checked for straightness. Getting the first course and the headlap right is what keeps the roof watertight and the pattern square.
Headlap (the vertical overlap of one course onto the next) typically runs about 3 inches, set by the manufacturer’s exposure spec. Side laps interlock on profiled tiles (S-tile, barrel) or butt on flat tiles. Each tile fastens through its pre-formed nail holes with corrosion-resistant nails or screws, driven snug but not tight, because over-driving cracks clay. Cut tiles at rakes, valleys, and penetrations are trimmed with a wet saw and fastened or clipped so no cut edge is left loose.
Finishing hips, ridges, valleys, and flashing
Hips and ridges are capped with matching ridge tiles set over a raised nailer or a mortar/foam closure, lapped away from prevailing wind, and the end tiles mechanically fastened. Valleys use preformed metal valley flashing, ideally with a raised center rib and cut tiles held back to leave an open waterway. Flashing, not tile, stops leaks at every transition, so these details carry more risk than the field.
Wall and chimney transitions need headwall and sidewall flashing woven into the underlayment and the tile courses, plus counter-flashing let into masonry. Pipe penetrations use lead or malleable flashings dressed over the tile profile. Because flashing is the leak-prone layer, it should be inspected as its own step. Clay tile itself lasts 50 to 100 years, but the flashing and underlayment are the parts that get renewed, which is a core theme in ongoing tile roof maintenance and underlayment care.
DIY or hire a pro? Clay tile labor realities
Clay tile installation is a specialist trade, not a typical DIY project. The tiles are heavy and brittle, the load and flashing details carry real structural and leak risk, and mistakes are costly to unwind after the roof is loaded. Most homeowners are better served hiring a crew experienced specifically with tile, not general shingle roofers.
Labor is a large share of a tile roof budget because the work is slow and skilled: loading tile safely, cutting profiles cleanly, and detailing hips, valleys, and flashing all take time. When you vet installers, ask for tile-specific references and confirmation the crew has done your tile profile and slope before. Our tile roofing company vetting guide walks through the questions that separate a real tile specialist from a generalist, and the broader learn about roofing hub covers adjacent decisions.
Frequently asked questions
What is the correct order of steps to install a clay tile roof?
The order is: confirm the structure can carry the load, prepare the deck, install drip edge and dry-in, lay underlayment (doubled on low slopes), set flashing, snap layout lines and install battens if used, lay field tiles from the eave up course by course, then finish hips, ridges, valleys, and penetrations. The dry-in and flashing steps happen before tile and do most of the waterproofing.
Do clay roof tiles need battens or can they be nailed directly?
Both are valid. Direct-nail (through the tile into the deck) is common on slopes from 2.5:12 to about 7:12 in dry climates. Battens, which are 1-inch by 2-inch nominal strips, are generally required on slopes steeper than 7:12 and are preferred in wet or freeze-thaw climates, especially with counter-battens that create a drainage gap. Slope, climate, and tile profile drive the choice.
What underlayment goes under a clay tile roof?
A single layer of 30-pound felt or a high-temperature synthetic or self-adhered membrane is standard on slopes of 4:12 and steeper. On slopes between 2.5:12 and 4:12, a doubled layer is generally required. Underlayment is the real water barrier under tile, so many owners re-lay the original tiles over fresh underlayment partway through the roof’s life.
What roof slope is required for clay tile?
Clay and concrete tile installs on slopes of 2.5:12 (about 21 percent) or greater under IRC Section R905.3. Below 4:12, expect doubled underlayment; above 7:12, expect battens. Below 2.5:12, tile is not a code-approved roof covering because water sheds too slowly through the laps.
How heavy is a clay tile roof and will my house support it?
Installed clay tile weighs roughly 9 to 12 pounds per square foot for standard profiles, and 12 to 15 or more for heavy barrel and mission tile, versus 2 to 3 psf for asphalt shingles. Many existing structures need reinforcement to carry it. A structural engineer should verify the framing before a conversion from a lighter roof.
Can I install a clay tile roof myself?
It is not recommended for most homeowners. The tiles are heavy and brittle, the structural and flashing details carry real risk, and errors are expensive to fix after the roof is loaded. Hiring a crew with tile-specific experience for your profile and slope is the safer route, and labor is a significant share of the total cost for that reason.
Reviewed by The Roofing Brief Team. Last reviewed July 2026.