1. What is an Asphalt Roof Shingles Calculator?

Definition: This calculator estimates the number of squares of asphalt shingles needed based on roof area and a waste factor.

Purpose: It helps roofing professionals and homeowners determine how many shingle bundles to purchase for roofing projects.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Shingles needed (squares)
• \( A_r \) — Roof area (square feet)
• \( S \) — Waste factor (1.05-1.10)

Explanation: The roof area is multiplied by the waste factor (to account for cutting and mistakes) and divided by 100 to convert to squares (1 square = 100 ft²).

3. Importance of Shingle Calculation

Details: Accurate shingle estimation ensures you purchase enough materials without excessive waste, saving time and money.

4. Using the Calculator

Tips: Enter the roof area in square feet and select a waste factor (default 1.10 for 10% waste). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is a "square" in roofing terms?
A: One square equals 100 square feet of roof area, typically covered by 3 bundles of shingles.

Q2: Why use a waste factor?
A: The factor accounts for cutting waste, starter courses, and mistakes during installation.

Q3: When should I use 1.05 vs 1.10?
A: Use 1.05 (5%) for simple roofs with few cuts, 1.10 (10%) for complex roofs with many hips and valleys.

Q4: How do I measure roof area?
A: Multiply house length by width, then multiply by roof pitch factor (1.0 for flat, up to 1.6 for steep).

Q5: Does this include starter shingles?
A: No, you'll need additional starter shingles for the eaves and rakes (typically 1 linear ft per sq ft of eave).