Do you need to replace or repair your roof? If so, you might be wondering how much it will cost you. One of the factors that affects the price of roof installation or maintenance is the size of your roof. But how do you measure the size of your roof?
How do you calculate the square footage of your roof? In this blog, we will explain what roof square footage is, why it is important, how to calculate it, and what common mistakes to avoid. So, without any further ado, let's get started.
What is Roof Square Footage and Why is it Important?
Roof square footage is the area of your roof measured in square feet. It is different from the floor area of your house, as it takes into account the slope and shape of your roof. Roof square footage is important because it determines how much roofing material you need, how long it will take to install or repair your roof, and how much it will cost you.
Roofing contractors usually charge by the square, which is a unit of measurement equal to 100 square feet of roof area. Therefore, knowing your roof square footage can help you estimate the cost of your roofing project and compare different quotes from different contractors. It can also help you plan ahead and budget for your roof installation or maintenance.
How to Calculate the Roof Square Footage of Your Roof?
Calculating the square footage of your roof is not as simple as measuring the length and width of your house and multiplying them. You need to consider the slope and shape of your roof, as well as the number and size of any dormers, skylights, chimneys, or other features that affect the roof area.
Here are the steps to follow to calculate the roof square footage of your roof:
Step 1: Determine the Pitch of Your Roof
The pitch of your roof is the angle or slope of your roof. It is usually expressed as a ratio of the rise (the vertical distance from the base to the peak of the roof) to the run (the horizontal distance from the base to the edge of the roof). For example, a roof with a 6/12 pitch means that for every 12 feet of horizontal distance, the roof rises 6 feet.
The pitch of your roof affects the roof area, as a steeper roof has more surface area than a flatter roof. Therefore, you need to determine the pitch of your roof before you calculate the roof square footage. There are different ways to measure the pitch of your roof, such as using a level, a tape measure, a smartphone app, or a pitch finder tool. You can also look up the pitch of your roof online based on the style of your house.
Step 2: Calculate the Base Area of Your Roof
The base area of your roof is the area of the horizontal projection of your roof. It is the same as the floor area of your house, plus any overhangs or eaves. To calculate the base area of your roof, you need to measure the length and width of your house and any overhangs or eaves and multiply them.
For example, if your house is 40 feet long and 30 feet wide and has 1 foot of overhang on each side, the base area of your roof is: (40 + 2) x (30 + 2) = 1,344 square feet.
Now, suppose you have a dormer that is 12 feet long and 4 feet wide, a skylight that is 2 feet by 4 feet, and a chimney base that is 2 feet by 2 feet. The areas would be calculated as follows:
- Dormer area: 12 x 4 = 48 square feet
- Skylight area: 2 x 4 = 8 square feet
- Chimney area: 2 x 2 = 4 square feet
Adding these areas to the base area gives you a total roof area: 1,344 + 48 + 8 + 4 = 1,404 square feet.
Step 3: Adjust the Base Area According to the Pitch of Your Roof
The base area of your roof is not the same as the roof area, as the roof area is larger due to the slope of the roof. To adjust the base area according to the pitch of your roof, you need to multiply the base area by a pitch factor. The pitch factor is a number that varies depending on the pitch of your roof.
The higher the pitch, the higher the pitch factor. You can find the pitch factor for your roof using a table, a calculator, or a formula. For example, the pitch factor for a 6/12 roof is 1.12, and the pitch factor for a 12/12 roof is 1.41.
Common Mistakes to Avoid When Calculating the Roof Square Footage of Your Roof
Calculating the roof square footage of your roof can be tricky, and there are some common mistakes that you should avoid. Here are some of them:
Not measuring the pitch of your roof correctly
The pitch of your roof can make a big difference in the roof area, so you need to measure it accurately and use the right pitch factor. If you measure the pitch of your roof incorrectly, you might end up with a roof area that is too large or too small, which can affect the cost and the amount of roofing material you need.
Not measuring the base area of your roof correctly
The base area of your roof is the foundation of your roof area calculation, so you need to measure it precisely and include any overhangs or eaves. If you measure the base area of your roof incorrectly, you might end up with a roof area that is too large or too small, which can affect the cost and the amount of roofing material you need.
Not adding the area of any dormers, skylights, or chimneys
These features can add to the roof area, so you need to measure them and include them in your roof area calculation. If you forget to add the area of these features, you might end up with a roof area that is too small, which can affect the cost and the amount of roofing material you need.
Not rounding up the roof area to the nearest square
Roofing contractors usually charge by the square, which is equal to 100 square feet of roof area. Therefore, you need to round up your roof area to the nearest square. For example, if your roof area is 1,660.28 square feet, you need to round it up to 17 squares. If you do not round up your roof area, you might end up paying more or less than the actual cost of your roofing project.
Conclusion
To wrap up, calculating your roof's square footage is crucial for estimating costs and materials for roofing projects. It involves measuring your roof's base area and adjusting the pitch to ensure accuracy. Common mistakes include incorrect measurements and overlooking features like dormers, which can affect your project's budget and requirements. To avoid these pitfalls and ensure a precise estimate for your roofing needs, consider consulting with professionals.
HP Roofing specialises in providing accurate assessments and high-quality roofing services. Contact HP Roofing today or fill out our contact form for reliable assistance with your next roofing project, ensuring it's done right from the start.
