STEP-BY-STEP MEASUREMENT GUIDE

How to Measure a Roof for Shingles: Safe & Accurate Guide

Measuring a roof for shingles requires determining total sloped square footage, calculating roofing squares, and converting square footage into bundles while adding a proper waste buffer. Follow our safe ground and plan-based measurement workflow.

Safe Measurement Rule

You do not need to walk on a steep roof to measure it accurately. Measuring ground footprint dimensions or using architectural drawings combined with a pitch multiplier yields exact surface area safely.

Step 1: Measure Each Plane or Building Section

Measure exterior wall lengths and add 12 to 24 inches for overhangs. For complex roofs with multiple dormers, gables, or valleys, sketch the roof from above and divide it into basic geometric shapes (rectangles and triangles).

Step 2: Apply the Roof Pitch Multiplier

Multiply the horizontal footprint of each section by the pitch multiplier:

$$text{Sloped Area} = text{Horizontal Footprint} times sqrt{1 + left(frac{text{Rise}}{12}right)^2}$$

Step 3: Add Waste Allowance & Calculate Bundles

  1. Add Waste: Add 10% for simple gable roofs, or 15% to 20% for complex hip roofs with multiple valleys.
  2. Convert to Squares: Divide total square feet by 100.
  3. Multiply by 3: Multiply squares by 3 to get total shingle bundles.

Worked Shingle Measurement Example

A home has an exterior footprint of $40text{ ft} times 30text{ ft}$, a $1text{ ft}$ overhang (adjusted dimensions: $42text{ ft} times 32text{ ft} = 1,344text{ sq ft}$), a $6/12$ pitch (multiplier $1.118$), and a 10% waste allowance:

  1. Sloped Surface Area: $1,344 times 1.118 = 1,502.6text{ sq ft}$.
  2. Add 10% Waste: $1,502.6 times 1.10 = 1,652.9text{ sq ft}$.
  3. Convert to Squares: $1,652.9 / 100 = 16.53text{ Squares}$.
  4. Total Shingle Bundles: $16.53 times 3 = mathbf{50text{ Bundles}}$.

Related Tools

Perform these calculations instantly using our Shingle Calculator, Roof Waste Calculator, and Roof Square Footage Calculator.