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.
Calculate The Square Footage Of Your Roof
Now that you thought about the slope and complexity of your roof, youre ready to learn how to calculate the square footage of your roof.
To get a rough estimate for your roofs square footage, youll use this equation:
For example, if you have an easy up and over, walkable gable roof and a house that measures 56 feet lengthwise and 28 feet widthwise, your calculation will look like this:
1,568′ =
x 1.3
2,038 = square feet of roof area
Using this equation wont be 100% accurate, but knowing your roofs square footage is a great jumping-off point to learn how much youll have to invest in your replacement.
How Do I Calculate The Slope For My Metal Roof
Calculating a slope for a metal roof is simple and only requires two numbers. As mentioned previously, the slope is calculated as a ratio of the rise to the run. The easiest way to make this measurement is with a level and a 12 carpenters square. Youll need to face the edge of the roof so that one side is lower than the other. In most cases, this will be on the end, or side.
To measure your roof slope , hold the carpenters square in front of you so that the long side is horizontal and the short side is vertical. Now rest the edge of the carpenters square on the edge of your level. You should be holding the level horizontally at eye level, with the carpenters square on top, pointing up.
Your level will have measurements on one or both edges. For example, if you have a 2 level, 24 will be marked along the edge. A 4 level will have 48 marked, and so on. Now align the end of the long side of your 12 square with the end of your level, so that the scales line up.
Lets assume you are on the left side and it is the low side. Find the left corner of the carpenters square and place it anywhere along the roofs edge. Now raise the level until the bubble on the level is between the two lines. When it is, both the level and the carpenters square are perfectly level.
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How To Calculate The Number Of Roof Shingles Youll Need
Before you start the calculation, you need to be aware that shingles are sold by the square and by the bundle. A square of shingles will be the amount needed to cover an area of 100 square feet. The shingle bundles will be plastic or paper-wrapped bundles that are made to be light enough for a single person to carry. This means that if you are going to be using heavier shingles, you will need to have more bundles to cover each square foot.
It is common to use 3 bundles to a square of shingles. However, if you are using heavier shingles, you will require 4 to 5 bundles for a square. When you are using 3 bundles for a square, you will be getting 29 standard shingles in each bundle.
How You Get Shingles
When you are replacing your roof, you need to calculate the number of roof shingles you need. There is nothing worse than being short on shingles because you will only realize this close to the end of your project. Of course, there are some measurements which will need to be taken before you are able to calculate the number of roof shingles that you need.
The Measurement Method
If you do not have any safety equipment, you will need to use a ladder to get one measurement while the others can be made on the ground. Of course, this will be assuming that your home is rectangular. When using this method, you will need to measure the rake of the roof while standing on a ladder. This is the length from the peak of the roof to the edge where our ladder will be sitting.
Asphalt Shingles Cost Breakdown
Here is a closer look at prices for different types of asphalt shingles.
| PRODUCT | |
|---|---|
| $45 + / bundle or $135 + / square | |
| Energy-Efficient | $40 + / bundle or $120 + / square |
In the past three years, from 2016-2020, prices have actually gone down by about 20%. This is great news for homeowners looking to get a new roof.
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Figure Out Your Homes Footprint
If you use the square footage of your home, youll only get a vague idea of what the square footage of your roof is. Thats why you have to figure out your homes footprint.
A person of average height will have a stride somewhere between 2 to 2.5 feet. To figure out your homes footprint, you can step off the dimensions of your roof by counting the steps you take to get the length of your home. You will then step off the width of your home.
After stepping off the length and width of your home, youll multiply the two numbers to get your homes footprint.
Length x width = your home’s footprint
Your calculations are going to be off, but measuring this way can give you a basic idea of your homes footprint. Keep in mind, square footage of a house does not equal the square footage of a roof.
Which Should I Use To Re
Asphalt, wood or slate are the preferred material for steep rooftops. However, when re-shingling a hip/steep one, consider the type of shingles that were used previously. Using a material of comparable weight and quality can help ensure that the structure is designed to support the new weight. If heavier ones must be used, then the home may need to be reinforced before the project can proceed.
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How Shingle Quantities Are Measured
Roof shingles are sold by both the bundle and by the square. A square of shingles is the quantity needed to cover 100 sq. ft. of roof. Shingles are packaged in paper- or plastic-wrapped bundles designed to be light enough for a person to carry, so heavier shingles require more bundles per square. Three bundles to a square is most common, which applies to most three-tab strip shingles and some lightweight laminated shingles. Heavier three-tabbed shingles and laminated shingles require four, or sometimes five, bundles to cover a square. When shingles come three bundles to the square, there are 29 standard-sized shingles in each bundle.
Figuring out the roof area is the first step to determine how many bundles youll need to order. There are two ways to size up a new or freshly stripped roof: the measurement method and the sheet-count method. Theres a third method for calculating bundles when youll be laying new shingles over old or if the old roof is still in place.
Once you have a bundle or square count for the main roof area, youll add additional shingles to account for waste, starter shingles, and extra shingles for hip and ridge caps.
Should You Consider Diy Roof Installation
As we discussed before, professional labor to install a new asphalt shingles roof constitutes at least 70% of the total cost. This means that you can potentially save thousands of dollars if you can do the tear off and installation yourself.
The million dollar questions is, should you?
When it comes to asphalt shingles, one of their biggest benefits is that they are extremely DIY friendly. Indeed, asphalt shingles is one of the very few roofing materials that a handy homeowner can put up on their own.
Shingle installation does not require any special tools or technical training. This is the reason why so many roofers install them its the easiest entry point in this field.
You can purchase all the necessary materials and supplies at your local big box home improvement store, and avoid the hassle of hiring a roofing company. In fact, basic 3-tab roofing shingles is one of the cheapest roofing options out there, and you can have a brand new roof for under $3,000.
Moreover, there are many step-by-step guides and YouTube videos on how do this correctly.
Keep in mind that when you buy shingles, you need to carefully measure your roof and also buy extra shingles to account for the waste factor. Typically, gable roofs require about 5% waste, while hip roofs are about 7.5%
Still, if you do everything carefully and educate yourself about the nuances of proper installation, you can do a very successful shingle install and keep thousands of dollars in your pocket.
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Raise The Roof Not Your Stress Levels
Talking to contractors can be nerve-wracking, especially when it comes to roofing projects. Since roofs can go yearseven decadeswithout needing work, many homeowners arent familiar with roofing terminology or what the typical job should cost.
Thats why we put together this handy guide for calculating how many shingles and other roofing materials your project will require. This basic information will help you start budgeting for your project and make it easier to evaluate contractors estimates.
Choose The Right Dumpster Size
Once youâve determined the approximate amount of roofing debris youâre working with, itâs time to choose a roll-off container to dispose of it.
If you give this information to the dumpster company over the phone, they will be able to recommend the ideal container size based on the type and amount of debris.
In most cases, a 10 or 20 yard dumpster will do the job.
Some dumpster rental companies wonât allow roofing shingle debris in 30 or 40 yard bins due to weight.
The weight of the shingles and the container itself can push the limits of the roll-off truck ‘s ability to lift the load.
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Instructions For The Shingle Calculator
Enter the approximate value for how many square feet the house has in the first number box.
Select how steep the roof is. A 4/12 pitch is relatively easy to walk, an 8/12 is very difficult to walk, and a 12/12 is impossible to walk.
Select the complexity of the roof. One roof line is simple, two to four roof lines is average, and anything over four roof lines is complex.
Choose whether or not your roof is new or will have multiple layers to remove.
Finally, choose what type of new roofing will be used.
This calculator is only an estimation. It is not as accurate as measuring each roof plane and adding the square feet together. It does take into account for an average number of offsets and an overhang. It also takes into account for the starters, the edges, and the ride caps. The squares returned include everything.
The formula for solving for the area of a roof involves climbing onto the roof. Measure each roof plane. For shapes such as trapezoids, triangles, and trapeziums, find the average length by finding the center of the width. Remember to add two feet for valleys. Add the square footage of all of the roof planes together. Divide this by one hundred for the number of squares. There are three bundles of shingles for each square.
To determine how many will be needed for starters and edges, measure the entire perimeter of the roof and divide it by three. Since there are twenty six shingles in a bundle of twenty year shingles , divide the result by twenty six.
How Do You Calculate The Roof Square Footage Of 1500 Square Feet House
Figure out the area of the house plus overhangs:- determine the squre footage of the shed foot print by measuring the length and width of the shed including the overhangs. Assume the overhangs are 1 feet both sides eves and rake then you have 2 feet extra, so each dimension for 30×50 = 1500 sq ft with overhangs is around 32×52 = 1664 square footage.
Find the roof pitch or slope:- the roof pitch is the amount of slope. The slope is described by the rise in inches or how far up it goes over the run in inches or how far horizontal it goes. We will use a 4 in 12 pitch. For every 4 inches the roof goes up to the peak it goes 12 inches horizontally.
Calculate the square of rise and run and sum it:- square of rise 4×4=16, square of run = 12×12 = 144, add both 16 +144 = 160.
Find the square root of the sum:- square root of 160 = 12.649
Sum divide by 12 to get the product:- square root of 160 = 12.649 is divided by 12 as 12.649 ÷ 12 = 1.054, hence 1.054 equals the product
Multiply the product by the flat roof area and divide by 100:- our house is 1500 square footage which as 1664 sq ft with overhangs, so 1.054 x 1664 = 1754 square feet, 1454 / 100 = 17.54 squares.
Add 10% for wastes and starter:- wastages 10% of 17.54 squares = 1.754, so final squares of shingles do you need = 17.54+ 1.754 = 19.294 squares, it is rounded to 19 squares.
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Shingle Roof Installation Cost
The total cost of installing a shingle roof consists of both material and labor costs. Labor is a significant factor and can comprise as much as 60% or more of the total project cost. So, for a job that ends up costing $12,000, at least $7,600 of that goes toward labor costs.
With labor, you may need to pay to tear off and dispose of the old shingles and underlayment. In some cases, it may be possible to leave the existing shingles in place and to install the new shingles on top.
How Many Nails Will You Need
Nails will also be required for any roofing project. The average 3-tab shingle needs four nails per shingle. High wind areas and other types of shingles may need more. 320 nails will be needed to install a square of standard 3-tab shingles, assuming four nails per shingle and 80 shingles per square.
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Calculating The Area Of A Complex Roof
Areas of complex roofs with multiple hips and valleys take the most time to calculate. Start by making a rough sketch of the roof. To simplify the calculation, break down the sketch into rectangles and right triangles , then take as many measurements of the roof as you can to match the sides of the rectangles and triangles on the sketch.
Use visual cues from the existing roof shingles or roof sheathing to determine square lines off eaves edges or ridges. These cues will help you measure the lengths of the sides of the rectangles and triangles. For instance, the cutout slots on shingled roofs run perpendicular to the eaves, and nail rows in sheathing are pretty close to square also. It is difficult sometimes to get accurate measurements. Dont get too concerned though just round lengths to the nearest 6 in.
With the sketch filled in with measurements, you can determine the size of the roof area. The area of a rectangle is length multiplied by width, whereas the area of a right triangle is the length of the two sides that meet at the 90-degree corner multiplied together and divided by two .
Tally the square footages of all the rectangles and triangles, which will give you the total square footage for the roof. The example here shows the calculation for a roof with two hips.
Calculating How Many Shingles You’ll Need
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