As a homeowner, you take your roof very seriously, or so we certainly hope. It’s your home’s first, and last, line of defense against the outside world and nature is always, repeat, always attacking your house. The sun is bombarding it with constant UV radiation in the intense heat, the changes in temperature are always trying to render your heat and cooling ineffective, animals are forever looking for ways in for shelter, and water will go anywhere that gravity will carry it if there’s an open path.

Because of these reasons, we recommend frequent inspections of your roof, lots of preventative maintenance, and of course, always coming to us for the best roofing service money can buy. We have decades of experience working with every type of roofing material, and we have seen every type of roof there is.

We believe that information is meant to be shared, and so we’re going to talk a little bit today about how you determine precisely how many shingles your roof needs. But before you do that, let’s talk about why it’s important to replace your roof at various intervals throughout its lifetime.

You see, no roof is immortal, no matter how well you take care of it, no matter how well built it is, sooner or later it must be replaced. When this happens, you want to know what it’s going to cost, and a big chunk of that is the purchase of materials. You’re not sure, just looking at your roof, how many shingles are going to be needed. Of course, assuming that the shingles you’re going to use are identical to the ones that are already there, you can always go up there and count them by hand, but you really shouldn’t do this. There are better ways to find out this kind of information.

Now, before we get into this, allow us to clarify that we’re not going to go into a lengthy lesson here regarding the mathematical calculations used to determine slope, ratios, or area. If you’re curious about these, we do have other pieces discussing exactly this elsewhere on our website, and of course, we’re happy to share this information with you directly should you contact us.

The purpose of this article is to get a good idea of how much a unit of shingles can cover, and therefore, how many shingles you’re going to need to cover your roof. This information, combined with service fees and labor costs, gives you an overall ballpark budget for a roof replacement.

One last thing to point out before we get into this is that a professional roofing company such as ourselves is more than ready to do all of these calculations for you, and deliver to you an accurate estimate of what things will cost, fully itemized showing how we came to these conclusions. We don’t recommend any do-it-yourself approach to roofing, but we know that people like to try to figure out things for themselves or to try to verify the claims of professionals, and there’s nothing wrong with that.

Roofing Squares

Shingles come in two units, bundles, and squares, with a square containing a certain amount of bundles. Each bundle will cover a specific area in square feet, with the average being something around four bundles per square, at between 25 to 30 feet per bundle in square footage.

With our recommended brand, Tamko, it tends to lean on the higher end of coverage, though it depends on which line shingle you plan to use. There is also a variation between three-tab shingles and architectural shingles, with the latter sometimes reaching up to a third of a square per bundle in coverage. Thus we want to point out that this is all just an estimation in the end.

Eaves Protection

Eaves protection comes in strips, which are on average about 60 to 65 feet long, though this varies depending on the product in question so again, this is just an estimate. You can calculate exactly how much of this you need very easily, by simply measuring your eaves and adding the lengths together.

Additional Materials and Variables

There are several additional variables to consider, such as underlayment area, valleys, ridgelines and hips, and so forth. Underlayment protection usually comes in 1000 foot units or more, while ridge and hip shingles tend to be about 20 linear feet per bundle, though sometimes they reach up to 40 feet per bundle depending on the product. Higher-end lines of these materials tend to cover more area; thus, you get what you pay for when it comes to roofing materials, especially shingles.

Fear of Waste

People will always tell you to overestimate rather than underestimate, and that’s not a bad piece of advice. People tend to fear wasting shingles, but truth be told, you’re going to be looking at about 10 to 15% as an average, acceptable range of waste for shingle materials. Frankly, some of them break, and some of them are defective because no matter what the brand, no matter what the contractor, there is no such thing as a waste-free project. That in mind, overestimating isn’t going to put much more of a dent in it, considering there has to be a little bit of slippage anyhow to account for damages and defects.

Math Needed

While we’re not going to get into how to do the math here, we are going to discuss the different forms of math need to determine precisely how many shingles you are going to have to buy depending on the coverage, geometry, and size of your roof as mentioned above.

While the slope doesn’t play as substantial a factor with the count of shingles, it is still important, due to ridges, hips, and valleys. This calculation is a linear measurement in feet versus a drop in feet, to produce a ratio. We have discussed this calculation and depth in the past but may do so again in a more dedicated piece down the line.

When it comes to things like ridge shingles, eaves protection, and other linear items, it’s all about measuring these lengths and adding them together, then over adjusting by about eight or nine percent.

When it comes to the area of your roof, we all know that we multiply one length by the other to get the area of a square or rectangular surface. Of course, we’re oversimplifying, because again, the math itself isn’t what we’re talking about here.

At JDT Construction, we will share this information, and how we came to the prices we did, but are more than happy to do all the calculations for you, as it’s much safer for us to be up on the roof in the first place.

To learn more about how to calculate the different variables needed for roof materials, fill out our contact form today.