How Do You Figure Out The Pitch of A Roof?

How Do You Figure Out The Pitch of A Roof?

Determining the pitch of a roof involves a simple equation: rise over run. In other words, how many inches in height does your roof increase for every foot of run? Calculating roof pitch isn’t difficult and can be done in less than two hours, on average. Accurate measurements are necessary for ordering roofing materials for new construction or a roof replacement. The roof’s pitch can help determine the type of materials to order, as some materials, such as asphalt shingles, are better suited to steep roofs than to flat roofs.

What Is Roof Pitch?

Roof pitch refers to the roof’s steepness or incline. “How steep is the roof?” is another way to ask for roof pitch. You can also think of roof pitch as how sharply the roof rises or what the slope of the roof is. Roof pitch is typically expressed in the form of a fraction.

What Materials Are Needed to Measure Roof Pitch?

There are various methods for measuring roof pitch, and the materials required will depend on the chosen method. Here is a list of tools and materials to have on standby:

• Tape measure
• Level
• Ladder
• Builder’s square
• Pitch chart
• Attic access
• Smartphone

How to Measure Roof Pitch

There are various methods of measuring roof pitch. The one you choose might depend on the type of materials you have, whether you have access to the attic space, and how comfortable you feel climbing a tall ladder. Remember to prioritize safety at all times.

Method One: Measuring Roof Pitch from the Top of the Roof Using a Tape Measure

If you feel comfortable climbing up to the roof, this is a straightforward method for measuring the roof pitch. To use this method, you’ll need a ladder, a 12-inch level, and a tape measure for accurate measurements. Here are the instructions for measuring roof pitch from the top of the roof itself:

1. Position the ladder at the edge of the roof, near the gutter.
2. Climb the ladder to the point where you can reach the top of the roof. (You don’t need to get on the roof to measure the pitch.)
3. Hold the level flat with one end touching the roof. Hold the level steady where the air bubble in the center is level.
4. Place the end of the tape measure at the 12’’ mark on the level, extending the tape measure and locking it at 24”. Ensure the tape measure is positioned at a perfect 90-degree angle to the level. This ensures an accurate measurement.

Method Two: Measuring Roof Pitch from the Top of the Roof Using a Builder’s Square

This second method of measuring roof pitch is similar to the first, but using a builder’s square instead of a tape measure. It can also result in a more accurate measurement in some cases. Measuring the roof pitch using a builder’s square could also be a good method if you only have access to the front roofline. Use these instructions and a builder’s square that has measurements on it instead of a separate tape measure:

1. Position the ladder where the edge of the roof is, near the gutter.
2. Climb the ladder to the point where you can reach the top of the roof. (You don’t need to get on the roof to measure the pitch.)
3. Place the builder’s square 12 inches from the roofline intersection.
4. Rotate the builder’s square until it’s perfectly vertical, according to the level.
5. Read the inside marking where the square intersects with the roofline.
6. Calculate the pitch of the roof by dividing rise by run.

Method Three: Measuring the Roof Pitch from the Attic

If you don’t feel entirely comfortable climbing a ladder to the top of the roof, it’s best to use the attic method. This is a much safer way to measure roof pitch if you have attic access. For this method, you’ll need a measuring tape, a 12-inch level, a pencil, and some clamps. Below are instructions for measuring the roof pitch from your attic:

1. Ascend the attic, bringing your materials with you.
2. Place the level against the sheathing and clamp it to a roof rafter if possible.
3. Adjust the level until the air bubble is centered.
4. Make a pencil mark precisely 12 inches from the end of the level.
5. Use the tape measure to determine the distance down from the deck of the roof to the 12-inch marker on the level, ensuring an exact 90-degree angle. This is your rise.
6. Next, measure the horizontal length of a single rafter. Rafter length is half the length of the roof span, or roof run.
7. Calculate the pitch using your measurements for rise and run. Remember, pitch is rise divided by horizontal run.

Method Four: Use A Pitch Chart to Estimate Roof Pitch

You can also measure the pitch of your roof using a printed pitch chart. This method isn’t as accurate, but it can be an easy way for homeowners to get a rough estimate of their roof’s pitch. Here are the instructions for measuring the pitch of a roof using a printed pitch chart:

1. Print out a pitch chart from a reliable website, preferably one that shows several different pitches. Make sure the image is printed to scale and not stretched.
2. Take the chart to the top of the roof (through the attic is fine).
3. Place it against the peak of the roof and fold the paper until it aligns with the roof’s pitch. This is your approximated roof pitch.

DIY Roof Measurements

DIY roof measurements, though they can be helpful for estimates, are not guaranteed to be accurate. Some methods of calculating roof pitch can be hazardous, while others are merely inconvenient. There are some advantages to calling in a professional. These include convenience, efficiency, and most importantly, guaranteed accuracy.