A 24 × 24 ft garage with a 6/12 gable roof and 12-in overhangs has about 756 sq ft of roof — 7.6 squares. Order 25 bundles of architectural shingles, including 7% waste.
| Item | Covers | Buy |
|---|---|---|
| Starter strip | 110 ft | 2 bundles |
| Hip & ridge cap | 26 ft | 2 bundles |
| Underlayment | 756 sq ft | 1 roll |
| Ice & water | 104 ft | 2 rolls |
| Drip edge | 110 ft | 12 × 10 ft |
| Nails | 2,518 nails | 1 coil box |
| Ridge vent | 16 ft | 4 × 4 ft |
Code runs it from the eave edge to 24 in inside the exterior wall, measured level — counted here from the wall's inside face, as Owens Corning requires. With a 12-in overhang and 6-in wall at 6/12 that is 47 in up the slope → 2 courses of 36-in membrane. Valleys get one 36-in strip centered on the valley line.
Exhaust 276 sq in → 16 ft of ridge vent at 18 sq in per ft. Intake 276 sq in → 31 ft of continuous soffit vent or 5 16×8 vents. Intake should match or beat exhaust; if your attic qualifies for 1/300 (balanced vents, plus a vapor retarder in climate zones 6–8), halve these.
| Line | Bundles | Est. cost |
|---|---|---|
| Architectural32.8 sq ft per bundle | 25 | $1,125 |
| GAF Timberline HDZ32.8 sq ft per bundle | 25 | $1,125 |
| OC Duration32.8 sq ft per bundle | 25 | $1,175 |
| OC Oakridge32.8 sq ft per bundle | 25 | $1,125 |
| CertainTeed Landmark33.3 sq ft per bundle | 25 | $1,075 |
| IKO Cambridge / Dynasty33.3 sq ft per bundle | 25 | $1,125 |
| Atlas Pinnacle33.3 sq ft per bundle | 25 | $1,125 |
| 3-tab32.3 sq ft per bundle | 26 | $1,118 |
Typical range $3,348–$5,616 · about $5.93 per sq ft of roof
One layer of old architectural shingles ≈ 0.9 tons and 3.8 cu yd. Book a 10-yard dumpster (about 1 tons included). Rentals run $395–$875; shingles hit the weight limit long before the bin is full.
Shelf prices from McCoy's (San Marcos, TX) checked Oct 23, 2026; GAF Timberline HDZ, IKO and Atlas shingles use a typical architectural price. Tap any price to use your supplier's.
| Pitch | Multiplier | Roof sq ft | Squares | Bundles | Ice & water rolls |
|---|---|---|---|---|---|
| 3/12 | 1.031 | 697 | 7 | 23 | 2 |
| 4/12 | 1.054 | 713 | 7.1 | 24 | 2 |
| 5/12 | 1.083 | 732 | 7.3 | 25 | 2 |
| 6/12 | 1.118 | 756 | 7.6 | 25 | 2 |
| 7/12 | 1.158 | 783 | 7.8 | 26 | 2 |
| 8/12 | 1.202 | 812 | 8.1 | 27 | 2 |
| 9/12 | 1.25 | 845 | 8.5 | 28 | 2 |
| 10/12 | 1.302 | 880 | 8.8 | 29 | 2 |
| 12/12 | 1.414 | 956 | 9.6 | 32 | 2 |
With 12-in overhangs the roof covers 26 × 26 ft = 676 sq ft of plan. A 6/12 pitch multiplies that by √(1 + (6/12)²) = 1.118, giving 755.8 sq ft. CertainTeed's waste table puts a 756 sq ft gable at 7%, so 755.8 × 1.07 ÷ 32.8 sq ft per bundle = 24.66, rounded up to 25 bundles.
As a hip roof the surface is the same, but the edges change: 104 ft of eaves and 78 ft of hips need 2 starter and 4 ridge-cap bundles, and the waste allowance rises from 7% to 16% — 27 bundles instead of 25.
Ice & water shield: (12 in of overhang + 6 in of wall + 24 in inside it) × 1.118 = 47 in up the slope, so 2 courses of 36-in membrane along 52 ft of eaves — 2 rolls of 65 ft after 6-in end laps.
The full method, material data and tips are on the main roofing calculator page.