To find how many squares are on your roof, divide your roof’s total square footage by 100. One roofing square equals 100 square feet. A 2,000-square-foot roof is 20 squares. That one number tells you how much debris a tear-off makes, and which size dumpster to rent for your roofing project in Green Bay.
This guide shows you how to measure your roof, adjust for pitch, and match the number to a dumpster size. It takes about 10 minutes.
What Is a Roofing Square?
Roofers measure in squares, not square feet. One square covers 100 square feet of roof. A roof with 1,000 square feet of surface is 10 squares. Dumpster companies size roofing jobs the same way, so knowing your squares makes getting a quote fast and accurate.
How to Measure Your Roof in Squares
- Measure each roof section. Most roofs are made of flat sections called planes. Measure the length and width of each one, then multiply them to get its square footage.
- Add the sections together. Add the square footage of every plane to get your total roof area.
- Divide by 100. The answer is your number of squares. Round up to the next whole number.
Example: a roof has two main planes that are each 40 ft x 20 ft. That is 800 + 800 = 1,600 square feet, or 16 squares.
How to Measure From the Ground
You do not need to climb on the roof. Measure the length and width of your house, including the overhang, to get the footprint. Then multiply by the pitch factor for your roof.
Adjust for Roof Pitch
Pitch is how steep the roof is. A steeper roof has more surface than its footprint shows. Multiply your footprint by the factor below:
| Roof pitch | Multiply footprint by |
|---|---|
| 4/12 | 1.05 |
| 6/12 | 1.12 |
| 8/12 | 1.20 |
| 10/12 | 1.30 |
| 12/12 | 1.41 |
Example: a house with a 1,500 sq ft roof footprint and a 6/12 pitch has 1,500 x 1.12 = about 1,680 square feet of roof. That is 16.8, so call it 17 squares.
Not sure of your pitch or the number of planes? Ask your roofer. The estimate should list the total squares. You can also see GAF’s guide on how to measure a roofing square.
What Size Dumpster Do You Need for Your Roof?
For a roof tear-off, size the dumpster by weight first and by volume second. Asphalt shingles are dense. A full load can hit its weight limit before the container looks full. This chart is a starting point for one layer of asphalt shingles:
| Roof size | Dumpster size | Price |
|---|---|---|
| Up to 15 squares | 10 or 15 yard | $200 / $230 |
| 20 to 30 squares | 20 yard | $270 |
| 30 to 40 squares | 30 yard | $300 |
| 40+ squares, steep, or 2 layers | 40 yard, or two hauls | $350 |
The 20-yard dumpster is the most common choice for homes. Our 30-yard includes 4 tons and our 40-yard includes 5 tons. When in doubt, size up to the next dumpster.
How to Estimate the Weight of Your Tear-Off
Use this formula: squares x pounds per square x layers ÷ 2,000 = tons.
Shingles usually weigh about 200 to 400 pounds per square, depending on the type. Architectural shingles are heavier than 3-tab shingles.
Example: 25 squares of architectural shingles at about 400 pounds per square, one layer, is 10,000 pounds, or 5 tons. With two layers, it doubles to about 10 tons, which is too much for one dumpster. For a full breakdown, see our guide on how much a roofing tear-off weighs.
What Changes the Size You Need?
- Extra layers: two or three layers of old shingles double or triple the weight.
- Steep roofs: more surface means more shingles.
- Decking and flashing: damaged wood and metal add to the load.
- Wet shingles: rain adds weight.
- Material: tile and slate weigh far more than asphalt.
Frequently Asked Questions
How many squares are in a 1,000 square foot roof?
A 1,000 square foot roof is 10 squares.
How many squares of shingles fit in a 20-yard dumpster?
A 20-yard dumpster usually handles about 20 to 30 squares of single-layer asphalt shingles. Weight can limit this, so check the included tons.
What size dumpster do I need for 25 squares of shingles?
A 20-yard dumpster is the usual choice for one layer of 25 squares. If you have two layers or heavy architectural shingles, step up to a 30-yard or plan two hauls.
Does the dumpster size depend on the roof pitch?
Yes. Pitch changes the roof’s surface area, so measure with the pitch factor to get the right number of squares.
What happens if my roof debris is too heavy?
You pay for the extra weight per ton. Read how overweight fees work before you book.
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