Roofing is weighed by the “square” — the material to cover 100 square feet. Weight matters because the roof structure must support it. This chart compares common materials.
| Material | Weight per square |
|---|---|
| Asphalt 3-tab shingles | 230 – 250 lb |
| Architectural asphalt | 350 – 450 lb |
| Wood shakes | 350 – 450 lb |
| Metal (steel/aluminum) | 50 – 150 lb |
| Concrete tile | 600 – 1000 lb |
| Clay tile | 600 – 1100 lb |
| Slate | 800 – 1500 lb |
One square = 100 sq ft. Heavy materials like tile and slate can weigh several times what asphalt does — the framing must be designed for it, often requiring an engineer.