How many bundles for a porch roof?

An 8×12 ft porch roof at 4:12 pitch is under 1 square — 3 bundles will cover it with waste and ridge cap.

Do porch roofs need ice-and-water shield?

Yes if the slope is under 4:12. Low slopes leak more easily; full-coverage ice-and-water shield prevents wind-driven rain from getting under the shingles.

Roofing Calculator for a Porch — Bundles & Materials

How the roofing calculator works

Roof area = house footprint × pitch factor. The pitch factor is √(1 + (rise/12)²): a 6:12 roof has a 1.118 factor. A "square" is 100 ft² of roof. Shingles are sold in 3 bundles per square.

Popular uses for the roofing calculator

Roofing for a House

Estimate shingle bundles and squares for a full re-roof.

Roofing for a Garage

Estimate shingle bundles and squares for a garage roof.

Roofing for a Shed

Estimate shingle bundles for a shed roof.

Roofing for a Porch

Estimate materials for a porch or overhang roof.

Roofing for an Addition

Estimate materials for a room-addition roof.

Frequently asked questions

How many bundles of shingles do I need?

3 bundles per roofing square. For a 40×30 ft home with a 6:12 roof: about 13.4 squares × 3 = 41 bundles.

What is a roofing square?

100 ft² of roof surface. Shingles are priced per square and packaged in bundles that cover ~33 ft² each.

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