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How Do You Calculate Roof Square Footage

How To Calculate Roof Area

How to Measure the Square Footage of a Roof

Easy to follow guide compiled by a roofing installation expert.

Installing a new roof is a capital intensive affair that requires you to establish your budget in advance. Thankfully, it is easy to estimate the costs by calculating the roof area and then using the sum to determine the cost of shingles per square foot.

Heres how to calculate roof area of your home:

Requirements: A strong ladder, large level, tape measure, marker, paper, and pencil.

1.) Measure the pitch

This is the first thing to do when you set out to calculate the area of your roof. Use your measuring tape to measure 12 inches on your large level and put a mark at the 12-inch line.

Place the ladder beside your building at the gable end. Ascend to the top of your roof. Thereafter, place the level against the gable trim and flat against the side of the house.

READ: How to estimate building costs

Use your measuring device to measure from the 12-inch mark on your level all the way to the bottom of the edge of your gable trim. This figure is your rise measurement.

Each rise dimension is inscribed as # in 12 and this is the pitch of your roof. For example, if your rise measurement is 4 inches, your roofs pitch is 4 in 12.

2.) Calculate the estimated roof area

When pressed for time, you can easily use your pitch calculation to get an estimated area of your roof. This is how to do it:

3.) Calculate the exact roof area

Follow these steps to figure out the exact area of your roof:

Calculate The Square Footage Of A Gable

To calculate the square footage of a gable wall section, you need to know the wall length and the height of the gable. If for some reason you canât get the height of the gable, you donât have a ladder long enough, or you are one of those that should not be at heights if you know the pitch of the roof and the wall length, you can also calculate the square footage of a gable.

How Do You Calculate The Square Footage Of Your Roof

Is it time for a roof replacement? Are you trying to figure out how much youll have to invest in your new roof?

If so, youre probably overwhelmed trying to learn everything that goes into the cost of your roof replacement. To help you understand the size of your roof investment, you first need to know the size of your roof. Thats why were going to break down how to measure your roofs square footage.

The team at Bill Ragan Roofing has been repairing and replacing roofs in Nashville and surrounding areas since 1990. We take extreme pride in everything we do, especially our workmanship.

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Convert Among Square Inch Square Foot Square Yard And Square Meter

You could, for example, perform all of your measurements in inches or centimeters, calculate area in square inches or square centimeters then convert your final answer to the unit you need such as square feet or square meters.

To convert among square feet, yards and meters use the following conversion factors. For other units use our calculator forarea conversions.

  • Square Feet to Square Yards
  • multiply ft2 by 0.11111 to get yd2
  • Square Feet to Square Meters
  • multiply ft2 by 0.092903 to get m2
  • Square Yards to Square Feet
  • multiply yd2 by 9 to get ft2
  • Square Yards to Square Meters
  • multiply yd2 by 0.836127 to get m2
  • Square Meters to Square Feet
  • multiply m2 by 10.7639 to get ft2
  • Square Meters to Square Yards
  • multiply m2 by 1.19599 to get yd2
  • How Many Rolls Of Felt Will You Need

    How to calculate square footage of a roof with different ...

    Roofing felt is sold by the roll. The average roll of 15-pound roofing felt covers about 400 ft2, or 4 squares, while the average roll of 30-pound roofing felt covers about 200 ft2, or 2 squares.

    Rolls of felt are 36 wide x 144 long for 15# and 72 long for 30#. Consider other underlayment options as needed, such as rubber or tar products.

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    How To Calculate Square Feet Of A Roof

    Before you do any roofing work, you must calculate the roofs square footage to determine how much material you need. Shingles and other roofing materials, such as underlayment, are typically measured in squares that are 10 feet long and 10 feet wide, with each square measuring 100 square feet.

    When calculating square footage for your roof, always add at least 10 percent of the total to account for waste.

  • Measure the length and width of every roof plane or surface. Include dormers . This information may be available on the homes original building plan or, if the roof surface is relatively low and flat, you can measure it yourself. If you cannot get up to the roof and measure safely, either hire a professional or make your best estimate of the roof surface dimensions.

  • Multiply the length and width of each square or rectangle-shaped plane. Calculate each plane separately. For example, if one roof plane measures 120 feet by 120 feet, 120 x 120 = 14,400 square feet.

  • Calculate the square footage for symmetrical, triangle-shaped planes by multiplying the length of the triangle’s base by its height . Then divide the total by 2 to get the square footage. For example, if a triangle-shaped roof plane measures 60 feet along the base and is 30 feet high, we have 60 x 30 = 1,800 feet, divided by 2 = 900 square feet for the triangle-shaped plane.

  • General Features Of Roof Square Footage Calculations

    Mostly a roof has an irregular shape, and many people have know any idea how to perform the calculation. There is nothing scary, you just need to divide the entire surface into individual shapes and to calculate each separately, and then to sum everything.

    If you only have a roof view on a paper, it is necessary to know its slope angle, and after receiving the projection area, to determine required materials for the actual space, this number has to be multiplied by cosine of the roof slope.

    If you decide to calculate the roof space by yourself, be sure to take into account that any material lies overlap and add 10-15% for waste. If the structure is complex, it is advised to add up to 20% of the waste.

    Also Check: Roof Overhang Extension

    What Is The Average Price Per Square Foot

    According to the latest estimates, the median price for each square foot for a home in the United States is $123 . But that can vary widely based on where you live and other factors. For instance, on the low end, youll pay $24 a square foot in Detroit. On the expensive end, in San Francisco, $810 . Aug 23 2019

    How Much Does A Tesla Solar Roof Cost

    How to measure a roof and calculate square feet. | 01/2020

    Availability Customers may place an order for Solar Roof today on the Tesla website. Installations of Solar Roof will begin in the U.S. this summer and we expect installations outside the U.S. to begin in 2018. 1 $21.85 per square foot is the price of a Solar Roof derived using similar methodology, roof size,

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    Gathering Measurements For Your Roof

    If you are choosing to do a DIY of the cost of your roof replacement without calling a professional to do it for you, then you will have to learn how to measure square footage of your roof, as all labor and material cost is going to be based on the total amount of area to work with. This is standard practice across all roofing companies, as most of the time the actual price for replacement is systematized with the actual space of the area.

    Roofing Pitch For Square Roof Area

    Finally, the more complex part, measuring your roofs pitch.

  • Estimate or calculate the pitch of your roof .
  • Climb to the peak of your roof. Bring a two foot level. Hold your level outward, perfectly horizontal from your roof, so the bubble is in the middle of the indicator glass. Then, using a tape measure, determine how many inches are between the middle of your level and your roof. .
  • Multiply the number of roofing squares by the following digits below.
  • Low Pitch: 1.07 x Roofing SquaresMedium Pitch: 1.185 x Roofing SquaresHigh Pitch: 1.36 x Roofing Squares

    NOTE:We understand a roofs pitch makes this process somewhat tricky. Enjoy Home Advisors free roofing square calculator right here.

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    Which Is More Affordable Solar Roof Or Regular Roof

    Solar Roof is more affordable than conventional roofs because in most cases, it ultimately pays for itself by reducing or eliminating a homes electricity bill. Consumer Reports estimates that a Solar Roof for an average size U.S. home would need to cost less than $24.50 per square foot to be cost competitive with a regular roof.

    Calculate The Surface Area Of The Roof

    Roofing Calculator

    Take the areaof the roofs footprint, say its 5,000 square feet, and multiply 5,000 by 1.118.

    That gives you 5,590 square feet, which is the actual area of the surface of the roof. And thats what you were looking for.

    This applies to rafter lengths as well as areas. A rafter for a roof with a 6:12 slope will be 1.118 times as long as the horizontal length that it covers.

    Also Check: How To Clean Solar Roof Panels

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    Draw Each Shape Individually Calculate Each Area And The Total Square Footage Of Your Roof

    Now we have eight shapes to find the area of six triangles and two rectangles. Instead of breaking out the old textbooks to calculate triangle areas, we like to use a triangle calculator. It makes figuring out the area of triangles a lot simpler.

    In the example above, we have two triangles with sides of 30, 20, and 20 feet. Pop those figures in the three-sides calculator and youll get an area of 198. Since we have two of those triangles, multiply by 2 for a running total of 396 square feet.

    We have four remaining triangles, all with dimensions of 15, 20, and 25 feet. That same calculator reveals a result of 150 square feet. Since there are four of those triangles, multiply by 4 to get 600 square feet.

    Lastly, we have two rectangles of 15 by 30 feet. This one is easy, just width times height for a total of 450 square feet for each one. Multiply by 2 and their total square footage is 900.

    Adding all the areas up yields a total of 1896 square feet . Since roofing material comes in 100 square foot squares, youll need at least 19 of them for your roofing project. Itd be wise to get at least 20 to account for mistakes and waste.

    Roof Slope Multiplier Chart

    We also have a much more complete roof slope multiplier chart that includes slopes by the half inch and slopes up to 30.5-in-12.

    If youre using the table below, you should consider getting yourself a construction calculator. That way you can instantly calculate the factor for any slope, among many other useful things. This one is very good.*

    Roof Pitch

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    Determine Roof Pitch And Slope Factor

    The pitch of your roof can dramatically increase its surface area, so its important to take it into account in your estimation. Simply use a 12-inch level to measure how many inches it rises for per foot it runs. This can help you determine your roofs slope factor. You can use pre-made tables online, or you can calculate it yourself. Simply square the rise and run of your roofs slope, add them together, then find their square root and divide it by 12.

    In this case, lets assume your roof has a pitch of 3/12, which means for every twelve inches of length, it will rise by two. Your roofs slope factor would then be equal to ) / 12 in, or 1.03078. Most tables will round this to 1.03.

    Average Shingle Roof Cost Calculations

    How to Calculate Square Footage | The Home Depot

    The average 2,000 square foot single story home will range from $9,000 to $11,000 or more depending on the type of shingle used. Additional factors that could lead to higher cost are how steep your roofs pitch is and the amount of dormers that have to be worked around.

    Generally speaking, roof cost will be different between manufacturer type and grade of shingle. For example, architectural shingles are twice to three times as thick and will cost more than standard asphalt shingles, while GAF shingles will generally be more expensive than IKO shingles, with warranty coverage matching price. As a general rule of thumb, the more upfront investment in a roofing material, the longer the manufacturer warranty, with GAF offering up to a 50 year warranty for installations.

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    How Do You Calculate Square Footage For A Roof

    Related Articles

    When a roof needs to be replaced, one of the first steps you may perform is figuring out the roof area. Both the roof area and pitch contribute to the cost of a roofing job. Calculate square footage for a roof by measuring and by performing some basic math equations. With the area measurement, you can learn the approximate cost of a new roof. Use this information if you are purchasing a home that needs a new roof or if your current home needs one.

  • Measure the ground dimensions of the house using a tape measure, and write down these dimensions. Multiply the length by the width to arrive at the ground area of the house. If the house has an irregular shape, measure each part separately, figure the separate areas and add them together.

  • Convert the area to roofing squares. Because each 100 square feet of roof is one roofing square, divide the total area from Step 1 by 100. The answer is the number of roofing squares for the roof.

  • Estimate the pitch of the roof. Roofs have one of three pitches: low, medium or high. A low pitch rises 3 inches every 12 inches of base horizontal length. A medium pitch rises 6 to 9 inches every 12 inches of base horizontal length. A high pitch roof rises more than 9 inches for every 12 inches of base horizontal length. Estimate the roof pitch by sight or calculate it with a level in the next step.

  • Things You Will Need

    How To Calculate Your Roof Area

    Knowing how to calculate your roof area can be a beneficial first step in estimating the cost of a new metal roof. In roofing we call the calculation of roofing materials needed a take-off.

    A good roofing contractor will take the time make sure that the take-off is accurate. Proper measurements and attention to roof details ensure that material shortages are avoided and prevent overages .

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    Do You Need Roof Repair Replacement Or New Installation In The Fort Worth Area

    If so, TX Roofing Solutions is the first choice for residents in the Dallas, Texas, area.

    Providing free, no-obligation roof inspections, our company can handle any service request you may have. Whether youre in Euless, Arlington, Flower Mound, Keller, Coppell, Grapevine or a surrounding area, were happy to provide you with honest, reputable roofing services.

    Call us today at 726-1369 or complete our form here to request your free, on-site roof inspection.

    Calculate The Complex Roof Areas

    How To Calculate Square Footage Of A House Roof

    Most roofs in Canada would be considered on the complex side. Multiple adjacent pitches, dormers, and turrets are common. Keep in mind that an experienced metal roofing contractor will need to factor in extended labour time for areas of your roof that will require precision metalworking skills.

    Start by finding the footprint area and multiply by the correct slope factor determined by pitch . In Figure 4 below, the dashed blue lines give a simplified view of the footprint. Multiply L x W to calculate the area for each rectangular section. Note the area of 77ft2 that needs to be subtracted for the recessed area.

    Once the footprint including overhang areas have been determined for each area, find the appropriate slope or pitch factor in the chart below. For example, a roof area with an 8/12 pitch has a slope factor of 1.202 so 2053ft2 x 1.202 = 2468ft2 total roof area.

    A Note about complex roofs: Complex roofs need more accessories and trims thaneasy roofs resulting in a slightly higher total cost/square foot.

    Figure 4. Calculating Complex Roof Area

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    Measuring The Length And Width Of Each Plane By Hand

  • 1Draw an overhead view of your roof. Each area on the roof is a single plane, which just means its a surface with a 2D shape, like a rectangle or square. Add lines where the different planes come together. Make sure to include all the planes, as well as any shingled sides of dormers your roof may have.
  • You dont have to draw this to scale. You just need a basic drawing of what your roof looks like.
  • Draw the roof like flat planes. Dont try to add perspective for the pitch. So if you have 2 rectangles meeting together at an angle, just draw 2 rectangles with a line in between.
  • 2Climb a ladder with a notepad, a pencil, and a measuring tape. Stow these items in a shoulder or hip pack while climbing for easy access. Wear closed-toe shoes with good grip and avoid working on wet or windy days.XResearch source
  • Use a sturdy extension ladder and prop it against the side of the roof. Make sure the ground is level underneath if its not, use plywood to even it out by placing pieces under one side. Tie the ladder to stakes to steady it on the ground, and then tie it with wire to a 20d nail driven into the roof.
  • To step onto the roof, hold on to the ladder extending above the base of the roof with 2 hands. It should extend at least 3 feet from the base of the roof.
  • Read the measurement and write it down on the small map you made of the roof, putting the measurements on the correct sides as you do.
  • Always be careful to balance yourself while youre making measurements.
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