Are you looking to get an accurate estimate for the materials you need for your next roofing job? We know just how tasking calculating shingle bundles needed for a roofing project could be, and in the text below, we will show you how to do this most effectively.

As a DIYer or a roofer, you always want to know ahead of time how many shingles in a bundle which you’d be using. This will allow you to be as exact as possible in doing a material estimate for a specific job so you can avoid the additional waste.

Waste could be as a result of too much of leftover materials. It could be in the form of extra spending from the second trip to the hardware store to get more shingles, something that’ll cost you more time and gas money.

All because you failed to make a good enough estimate and run short of material while on the job.

To save you all of that hassle, here is a simple guide on how to most accurately determine how many shingle bundles are needed for your roof.

## 1. CALCULATING QUANTITY FROM HOW MANY ARE IN EACH BUNDLE

When it’s time to order or purchase the roof shingles to be used, you’d find that they are sold in two ways: by the square and by the bundle.

One square (1 sq.) or one unit is some shingles you will need to cover about a hundred square feet of roof (100 sg. ft.)

Shingles come packaged in plastic or paper –wrapped shingle bundles that are usually light and portable enough for one person to carry.

When the roofing materials you have chosen for your roof are heavier, the manufacturer packages fewer shingles in the bundle for easy handling.

For this reason, the heavier shingles will require you to purchase a greater amount of shingles per square.

The common math that works for normal bundles is about three bundles per square, but you could need as many as four or five bundles for each square if you are working with the heavier material.

Making the mental note of three- to-one works great in an application for most laminated shingles and three- tab strip shingles of lighter weight.

You would usually be fine working with 3:1 for each square for with normal shingles, and in each bundle they come with about 29 standard-sized shingles, measuring 12 inches by 36 inches.

## 2. MEASURING THE ROOFING AREA FOR THE SHINGLES

Correctly figuring out the area of your roof is a great place to begin the calculations for the required bundles of shingles.

Many homeowners make the mistake of equating the quantity of roofing material they’d need to the house’s square footage.

Most roof surfaces are much larger in area than the footprint of the home they cover. This is because roof surfaces have slopes and overhangs that are unaccounted for and use up more surfaces.

To be more accurate in calculations for materials needed for the roofing project, you would need to measure the dimensions of every part of the roof’s surface.

That is, you would need to measure along every slope and from edge to edge. Your final area should include features such as dormers, chimney crickets or pipe jacks.

These are the kind of details you would need to be as accurate as possible.

Generally, two methods are possible to be painstakingly exact in your measurements: the single count method of the sheet –count method.

For more detailed instructions on how to measure your roof’s square footage. Check out this video: http://www.youtube.com/watch?v=qoyN-eQi5zw

## 3. THE MATH INVOLVED: MAKING THE ACTUAL CALCULATIONS

After obtaining or determining the dimensions of your roof surface, calculate the area of each part by multiplying the width by the length.

Add all of the areas together and when you have that total area, dividing by 100 will give you an estimate of the number of squares of shingles/ bundles you’d need to purchase for the roofing.

Based on the surface area calculations, if your total number is about 3,500 (the actual math would be 3,500 ÷ 100 = 35); and this would mean you need about 35 squares of shingles to install of replacing the roof in question.

The majority of manufacturers will recommend adding a waste calculation of 10 percent to the total.

So once you’ve obtained your total count for the roofing area, you’ll need to factor in that extra shingles for every hip, valley or ridge cap, and other obstructions like chimneys.

You’d also need to consider starter shingles that may or may not be salvaged.

## 4. USING TECHNOLOGY TO GET QUICK ESTIMASTES

As far as the calculations go, you can use an alternative easier method to get approximate numbers. There are many apps that do the math faster and smarter, with either an iPhone or Android smartphone.

Dozens of them actually, including Roofing Calculator (roofingcalculator.org)that can give you a breakdown in a few seconds of how many shingles in a bundle and how many your roof needs.

To use any of these apps without getting on your roof to make the measurements yourself, you will need to pay a detailed report from a company like Eagleview.

Solution providers like them have aerial camera systems that capture professional satellite images.

Eagleview’s King of technology is able to give you most of the information you would need for your roofing project including area and square footage.

(This YouTube video details some other mistakes to avoid when making calculations for installing of replacing roof shingles:

## 5. ACCOUNTING THE WASTE

There are few roofs that are simple enough to generate no waste, during installation. One of such is a style we rarely see in residential houses: the gable roof.

Its length is a whole number that is standardized and can typically be divided exactly by the shingle’s 3-ft. length. Most other types of roofing will require cuts for rakes and other obstruction or features on the roof’s surface.

A few things will determine how much of a waste factor you need to expect. The type of shingle, for instance. In that, laminated shingles will generate less waste if used with the same techniques as three-tab shingles.

The reason is they do not require as much maintenance or uniformity in the cutout patterns.

In any cases, it is always best to plan to waste more than you would so you do not have a shortage of shingles. The worst case scenario is that you’d be left with a few shingles in bundles that can easily be returned to get money back.

The rule of thumb here is that the more complex the roof is, the higher the waste factor. Although, there is no exact way to calculate a definite number for the extra shingles requires for waste.

Damage is another way that waste is generated during the installation process.

Some types of damage are often unavoidable, for example in moving them around a steep-sloped roof, there is always a high chance of some sliding off the roof and being unable to be salvaged.

Also if you wind up with a quality but sloppy roofing team that carries out the job in a way that is haphazard, you will likely need more bundles of shingles than your initial estimate.

## 6. FINAL NOTE

To conclude, it is worth noting that your measurements and calculations could never be as exact as you’d like them to be.

Use visual and mental cues where you can to help measure the number of shingles you would need.

To have numbers calculated for your roof’s square footage is a good start, but human error and waste factor from the installation process could be unpredictable and need to be included.

Below is a summary of how to best evaluate how many bundles you will need for your next roofing project:

Determine the kind of roofing material you would use (heavier or lightweight)

Normally, there are 29 shingles of the standard size in each bundle and three bundles to each square.

Manually calculate the area of your roof, keeping in mind that the features of your roof are often unique and need to be included in measuring.

Alternatively, you could use Eagleview for a rough estimate and a roofing calculator (See link to recommended free app here: http://www.roofingcalculator.org/free-app.php)

Be sure to account for a higher waste factor estimate to avoid running out of shingles.

Our desire is for your roofing jobs and DIY projects to be as seamless an experience as you’d imagine possible, please feel free to contact us for more information and leave a comment below.

References:

http://www.roofpedia.com/estimates-and-squares-how-many-shingles-will-i-need

http://www.eagleview.com/Products/PropertySolutions/EagleViewReports.aspx

http://www.roofingcalculator.org/how-to-use-our-free-roofing-calculator.php