Tile Roof Calculator
Tile roofs are not estimated like shingles. Clay and concrete tile is sold by the piece, weights 3 to 4 times what asphalt does, and almost always needs two layers of underlayment plus optional battens. This calculator takes your roof footprint, pitch, tile profile, and install method, then returns the exact tile count, hip and ridge tiles, underlayment rolls, batten linear feet, fasteners, and total deck load. Use the deck load number to confirm your rafters can carry the tile before you order — most existing asphalt-framed roofs need a structural review before going to tile.
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Length along the ridge
Eave-to-eave width across the building
Tile typically requires 4/12 minimum; below 4/12 you must use a double underlayment system
Coverage and weight vary by profile — mission/barrel uses a separate pan and cover, so the count is roughly double
Total linear feet of all ridges plus hips combined
Batten installs are standard for clay; concrete tile can go direct to deck if the manufacturer allows
Equal to tile exposure (gauge) — typically 11 to 14 inches for most profiles
15% for simple gables; 18-22% for hips, valleys, and complex cuts (tiles break during install)
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How It's Calculated
1. Roof Area = Length × Width × Pitch Multiplier × (1 + Waste) 2. Squares = Roof Area ÷ 100 3. Tile Count = Squares × Tiles per Square (varies by profile) 4. Hip/Ridge Tiles = Hip + Ridge Length ÷ 1 ft per tile 5. Underlayment = (Actual Roof Area × 1.15 × 2 layers) ÷ 200 sq ft per roll 6. Battens = Actual Roof Area ÷ Batten Spacing (ft) 7. Fasteners = Tile Count × 1.5 8. Deck Load = Actual Roof Area × Weight per Sq Ft
Worked Examples
1,120 sq ft footprint × 1.083 × 1.18 = 1,432 sq ft total area. At 88 tiles/sq that is ~1,260 clay Spanish tiles, ~60 hip/ridge pieces, ~14 rolls of 30 lb felt for double underlayment, ~1,213 linear feet of 1x2 battens at 12-inch spacing, and a deck load of about 10,920 lbs.
1,900 sq ft footprint × 1.118 × 1.20 = 2,549 sq ft. At 88 tiles/sq, ~2,243 concrete tiles, 120 hip/ridge tiles, ~25 felt rolls, ~1,820 lin ft of battens at 14-inch spacing, and a 21,240 lb deck load — heavy enough that a structural review is mandatory.
480 sq ft × 1.054 × 1.15 = 582 sq ft. Mission tile uses a pan and cover, so at 190 pieces/sq you need ~1,107 individual tiles, 24 ridge tiles, ~6 felt rolls, and a 6,070 lb deck load on a 12-lb-per-sq-ft profile.
Assumptions & Waste Factor
- Coverage figures are industry averages; verify with the manufacturer spec sheet
- Two layers of 30 lb felt underlayment are assumed (common code requirement for tile)
- Hip and ridge tiles use ~1 piece per linear foot at standard exposure
- Battens are 1x2 pressure-treated pine running horizontally across the slope
- Fasteners average 1.5 per tile (every tile at perimeters, every other in the field)
- Deck load uses the dry weight of the tile only, not water absorption or live load
Tile waste runs higher than asphalt or metal because individual pieces break during install, especially when cutting hips and valleys. Use 15 percent for a simple gable, 18 percent for a hip roof, and 20 to 22 percent if the roof has valleys, dormers, or radius cuts. Always order at least one extra bundle from the same dye lot for future repairs — discontinued tile can be very hard to match.
Frequently Asked Questions
How many tiles do I need per square?
It depends on the profile. Concrete flat tile averages about 90 per square (100 sq ft), concrete and clay S-profiles run 88 per square, clay flat tile is around 170 per square, and clay mission or barrel tile uses a pan and cover so the count roughly doubles to about 190 per square. Always confirm against the manufacturer coverage sheet, since exact exposure varies.
How much does a tile roof weigh?
Concrete tile weighs 9 to 12 lbs per square foot and clay tile weighs 8 to 12 lbs per square foot. By comparison, asphalt shingles weigh 2 to 4 lbs per square foot. A 2,000 sq ft tile roof can add 20,000 lbs of dead load, which is why a structural engineer needs to verify the rafters and trusses meet IRC Section R802 before you re-roof from asphalt to tile.
Do I need battens for a tile roof?
Battens are standard for clay tile and for any tile install in cold climates where ice damming is a risk. Many concrete tile manufacturers allow direct-to-deck installation in dry climates if you use a self-adhered underlayment, which saves the cost of battens. Check the manufacturer spec sheet — going direct-to-deck without their approval can void the warranty.
What is the minimum pitch for a tile roof?
Most tile manufacturers require 4/12 minimum slope. Between 2.5/12 and 4/12 you must install an extra layer of underlayment (a self-adhered SBS membrane is typical). Below 2.5/12 most manufacturers will not warrant their tile, and you should use a different roofing system.
Why do tile roofs need two layers of underlayment?
Tile sheds most of the water, but small amounts always make it under the tile through wind-driven rain and capillary action. The underlayment is the real waterproof layer. Two layers of 30 lb felt or a single layer of SBS-modified self-adhered membrane provide redundancy and last as long as the tile above them. Many jurisdictions, including most of Florida and California, require double underlayment by code for tile.
How long does a tile roof last?
Clay tile lasts 50 to 100+ years. Concrete tile averages 50 years. The tile itself often outlasts the underlayment underneath, so plan on stripping the tile and replacing the underlayment around the 40 to 50 year mark even if the tile is reusable. Reusing the original tile cuts the cost of an underlayment replacement by 40 to 60 percent.
Can I walk on a tile roof?
You can, but only on the lower third of each tile where it overlaps the tile below — that is the structurally supported area. Stepping on the high point of a tile cracks it. For inspections or repairs, use a roof ladder hooked over the ridge and only step on tiles where you can see the rafter line underneath.
How is tile attached to the roof?
Tile is fastened with copper or stainless ring-shank nails, screws, or hurricane clips. The exact attachment depends on the wind zone — a low-wind area might require one nail per tile in the field and every tile at the perimeter, while a high-wind coastal zone may require two clips and a foam adhesive bead under every tile. Always check the local wind zone before specifying fasteners.
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Disclaimer: This calculator provides estimates for planning purposes only. Actual material requirements may vary based on site conditions, installation methods, and other factors. Always consult with a qualified professional before making purchasing decisions.