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# How To Find Square Footage Of A Roof

## General Features Of Roof Square Footage Calculations

How to Measure the Square Footage of a Roof

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.

## One: Get Up On Our Roof Safely And Take Initial Measurements

Sketch out the shape of your roof on graph paper. In this example, youd only need to measure the overall width and length, the central ridge, and one of the hips . If you have a more complex roof shape with dormers, take all the measurements you can and prepare to use your eraser to refine the image of your overall roof structure. Make sure you have solid footing and if possible, use fall protection to keep yourself safe. Be mindful of hazards like ridge vents. Note the lengths in feet:

## Roofing Square: How Its Calculated And More

Can there be anything more exciting than building your own property? There are so many things that go into building your establishment, be it commercial or residential.

You have to think of the location, the layout, the size and measurement of the rooms, and so much more. The type of roofing you will opt for is another important aspect to take into account. While all of this sounds exciting, it can be equally tedious.

When you leave it to a contractor to choose a roof type for your home, or to replace the roof in your home, you may come across them using the following term, roofing square to describe the size of your roof.

No matter how good you are at math, you may have found that your calculations in terms of how much roofing supplies are required to put up the roofing system in your home are entirely different from what the roofing contractors you hired calculate them.

When it comes to building roofs, there are two important aspects to keep in mind:

• Roof measurements
• Roofing materials estimation

The one word that commonly gets thrown around in the world of roofing construction is roofing squares. Lets look more into what a roofing square is and why and how it matters in evaluating the shingles or roofing materials you will require in the following sections.

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## Figuring Out The Square Footage Of Your Roof

While it may seem difficult at first, you can divide your roof into 10 x 10 roofing squares, a standard unit of measurement used by roofers.

But first, some terminology youll need to know:

• Ridge Where two sloped roof areas meet
• Valley Where two sloped roof areas meet , often with a metal channel running along the fold
• Hip Roof Type of roof where all sides slope downwards to the walls
• Hip End The triangle shaped end of a hip roof

Related: Roofing 101: What Are the Different Parts of the Roof Called?

## Estimating Materials Based On Actual Measurements

Measuring each roof plane requires you to actually go onto your roof. If your roof has a number of planes and numerous hips, ridges and valleys, this is the most accurate way to calculate the materials needed. Take a metal tape measure and a pen and paper. Measure each planes length and width. Record your measurements. Once you are safely on the ground, use your measurements to determine the square footage.

For rectangular areas, multiply the length by the width. For example, if a plane measures 30 feet by 100 feet, this would be 3,000 square feet. For triangular areas, you may need to dust off your geometry book. If the area forms a right triangle, you can make use of the Pythagorean theorem. Otherwise, you might want to look up how to calculate the semiperimeter and then use Herons formula to find the area. Be sure to add extra for valleys, hips and ridges.

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## How To Calculate Square Footage Of A House Roof:

To calculate the square footage of a roof, measure the length and width of each plane on the roof . The plane of the roof is one side of the roof that has four separate edges. A dormer is a structure that sticks out of the roof and typically contains windows. After measuring the roofs plane and dormers, multiply the length times the width. Go onto the other side of the roof and measure the other side of the roofs plane, and include any dormers on that side as well. Multiply the length times the width on that side of the roof. Take the measurements from both sides of the roof and combine those numbers to get the total square footage of the homes roof.

#### How to calculate square footage of a 2-story house:

To calculate the square footage of a 2-story house, simply measure every room in the house. Exclude any unfinished areas, such as the garage or an unfinished basement. After measuring each room individually including the closets in each room combine the measurements from all rooms. The total number is the square footage of the 2-story home. While the thought of measuring a 2-story home may seem daunting, it is best to think of the house as a collection of individual boxes. After compiling the measurements of each box, you will have your total square footage calculation for the entire home.

## Determine The Roof Slope Multiplier

Note: If you already know the roof slope in degrees, then all you have to do to find the roof slope multiplier is find the secant using a scientific calculator.

For example, if the roof slope angle is 45Â°, then sec = 1.414213. That will be your roof slope multiplier.

So, to proceed.

Once you havethe slope of the roof expressed in standard pitch, you can consider yourself in possession of the lengths of the a and b sides of a right triangle. Now you need to pull out your trusty Pythagorean Theorem and figure out the length of the hypotenuse.

A good calculator can be found at web2.0calc.com.

As Im sure you remember, aÂ² + bÂ² = cÂ². So, if your slope is 6:12,

6Â² + 12Â² = cÂ²

36 + 144 = cÂ²

13.416 = c

So 13.416 is the length of the hypotenuse.

Now that youhave the length of your hypotenuse, 13.416, you want to think of that as the length of a line on the actual sloped roof surface over a horizontal distance of 12 inches. You want to find out how much longer that line is than the 12 inches it covers.

You will express this difference as a number, called the roof slope factor .

Once you know the roof slope multiplier for any particular slope, you can use it to find the actual area of any size roof with the same slope.

So in this case, for every 12 inches the roof goes across horizontally , while rising 6 inches , theres actually 13.416 inches of roof .

If you divide the 13.416 inches by the 12 inches , that gives you 1.118.

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## Which Tools Should I Use To Calculate Square Footage Of A House

When calculating square footage, real estate agents typically use a laser distance measurer, which is an electronic tool that is easier and less cumbersome to use than a measuring tape. To use the laser distance measurer, place the device on one wall and aim it at the wall directly across from it. The device will then display the square footage on the screen.

If you dont have a laser distance measurer, you can also calculate square footage with the following:

• Other ways to check the square footage of a home:

While less common, there are certain circumstances where buyers or renters are unable to tour the property in person and may buy or rent a home without visiting it first. If that is the case, there are other ways of checking the homes square footage. Even if you have physically visited the home and completed measurements on your own, it is always a good idea to double-check square footage measurements to ensure your numbers are correct.

• Check the property records held by your city or county

• Have the house measured by an appraiser

• If you are preparing to sell your house and are unclear on your homes square footage, it may be worthwhile to hire an appraiser to professionally measure your home. In addition to providing measurement information, the appraiser will also provide your homes value giving you peace of mind when you list your property.

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## Pound Felt Covers How Many Square Feet

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

Roofing comes in 3-foot-wide, 36-foot-long rolls that cover around 1 square. Roofing felt, often known as tar paper, is placed down initially when roofing over bare wood. A roll of 15-pound felt will cover around 4 squares, whereas a roll of heavier 30-pound felt would cover approximately 2 squares.

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## What If You Have A Steep Roof

To measure a steep roof, use one of the following alternate methods:

#### Method 1

Calculate the roof length by measuring the exterior walls plus the overhang for the length of the house parallel to the ridge.

Next, throw a rope over the ridge and mark it where it meets each eave. This will give the width dimension to use in figuring your area. This should be done on each roof section containing a horizontal ridge.

#### Method 2

Determine the roof area by using a mathematical formula that accounts for the roof length, total span, and roof pitch:

• Determine your roof pitch by using a pitch gauge or a smartphone app .
• Measure the length of the roof surface, including overhangs.
• Measure the span of the roof, including overhangs.
• Multiply the length x the span. The result will be the plane area. Use the chart below to calculate the total area of the roof.
• Calculate the total roof area Plane Area x Correction Factor = Roof Area
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## Get A Budget Roofing Quote That Means Something

So now when you call your favorite roofing service provider, you can ask them to give you a budget quote based on an internet measurement. When the roofing company starts asking those nosy questions like what is the address? How many stories is this home? What kind of roof are you wanting to put back? Are you the current owner? You will know why they are asking. Some roofing companies use pay services to get satellite takeoffs for their roofing quote, and they are very detailed. For homes that are just looking for a number, this is just not cost efficient for the roofer. They are usually more cost efficient for the very large homes and commercial type properties.

## 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.

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## Calculate The Exact Roof Area

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

• Take your pitch number and divide it by 12. For example, if your pitch is 4 in 12, you need to divide 4 by 12. The answer will be 1/3.
• Next, you need to square your outcome. In our example, 1/3 squared will yield 1/9.
• Calculate the square root of your new number: The square root of 10/9 is 1.05.
• Measure the length of your house including the overhangs.
• Measure the width of your house including the overhangs.
• Multiply the length of your house by its width to get the area. For example, 40 feet x 20 feet = 1,200 square feet.
• Thereafter, multiply the area by the pitch to get the true roof area: 1,200 x 1.05 = 1,260 square feet.

In order to allow for ridges, hips, and waste, it is advisable to add 10% of your final roof area for a gable roof or 17% in the case of a cottage roof.

As a result, you should be working with 1,386 sq. feet or 1,474 sq. feet for a gable roof or a cottage roof respectively. Get to know more about us!

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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.

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## What About The Waste Factor Should I Order Extra Roofing Materials

You want to order extra material to account for waste. Waste factors vary.

10%-15% is a good rule of thumb, but your results may be different. More complicated roofs will have a higher waste factor because there are usually more cut shingles around corners, walls, and edges.

It is okay to have a few shingles left over. They can be saved in case there is roof damage later or if repairs need to be done in the future.

So for the 24 square roof example, you would want to add 2.4 squares which equal about 7 or 8 more bundles.

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## How To Calculate Number Of Roofing Shingles

How To Calculate Roof Area

Fortunately, you don’t have to make a haphazard shingle estimate when planning for your roofing project: your roof size and chosen shingle type will guide the purchase process.

Shingles are sold in prepackaged bundles, not individually. Roofing manufacturers take the guesswork out of how many bundles you need per squareit’s listed in the specifications of each shingle they make. The specs for any given shingle will tell you how many bundles make up a square, how many shingles are in a square, and even the approximate number of nails you’ll need per square.

Often, three bundles of prepackaged asphalt shingles make one square, as is the case with the Timberline® HDZ Shingles. That said, the number of bundles you need can vary depending on shingle design. For example, five bundles of architectural asphalt shingles with artisan-crafted shapes, such as the Grand Sequoia® Shingle, cover one square. Once you know the number of squares of material your roof needs, check the shingle manufacturer specifications so you get your hands on exactly what you need.

If you’re still deciding on the perfect shingle for your roof, play around with the GAF VirtualRemodeler. The free online tool helps you envision how different shingle colors and styles would work with your home’s style. Be sure to keep local building codes in mind as you weigh your shingle options..

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## How Big Is A Square In Roofing

The calculations above will give you the total number of square feet of the roof area.

As you have noticed in the roofing industry however, the surface of the roof is being measured in squares. This refers to the roof area that measures approximately 100 square feet.

Therefore: 1 Square in Roofing = 100 square feet

Now, in order to determine how many squares are there on the gable roof for example, all you need to do is divide the total square footage by 100.

• Total square footage from Example 2 above: 28,000 sq. ft.
• Number of squares for 2 planes: 28,000 sq. ft. Ã· 100 = 280 squares

This means that both planes of the roof will require 280 squares of shingles. A three-tab shingle, which is most commonly used, is packed in 3 bundles per square.

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