If you are looking for information on “how to measure the roof”, you have come to the right place. This article will guide you through the five basic steps.
How to measure the ceiling: Step n. Tip #1: Make Your Drawing
A good place to start is to make a bird’s eye view sketch of your roof. Visualize the ceiling as if you were a hundred feet above it looking down. What would you see? Draw the outline of the entire roof. Then show each eave, rake, valley, hip, and ridge. Show all the details, including pipes, vents, chimneys, skylights, and solar panels. All of these things affect your estimate of roofing costs. Try to keep your drawing somewhat proportional, but it doesn’t have to be drawn to perfect scale.
How to Measure the Roof: Step #2 – Measure the Slope
I like to measure the slope first, because it is important and easy to forget. This method requires a carpenter’s level (any length will do) and a tape measure. Place one end of your level on the roof with the other end pointing directly “downhill.” Raise the downhill end until the bubble is centered. Then, keeping the tape measure vertical, measure the height, which is the distance from the bottom of the level to the ceiling.
If your level is a foot long, you’re all set. What you see is what you get. If your level is two feet long, divide the rise by two. If your level is three feet long, divide the rise by three.
On roofs with high-profile roof components, such as shingles or wood battens, you may need to lay a board in multiple rows to get a true reading.
Sometimes it is easier to measure the slope of the fascia board or drip edge rather than the roof surface. As long as it’s parallel to the ceiling, it doesn’t matter what you measure.
Record the slope directly on your drawing.
How to Measure the Roof: Step #3 – Taking Measurements
Then record the measurement of each vertical, horizontal, and diagonal line on your drawing. They will all be necessary to calculate the correct amount of roofing material you will need. Also be sure to measure each roof section from the eave, straight up the roof to the peak.
The easiest tool for measuring most roofs is a measuring wheel. It’s fast and doesn’t require anyone else to hold the other end of the tape. But it is a mechanical device and you need to make sure it works properly.
The most accurate tool for measuring is a tape. It’s also useful for some roofs, like barrel tiles, where a wheel doesn’t roll very well. I use a footer of 25 and 100 feet.
It’s much easier if you round each measurement to the next larger foot. I’ve also found that if roofers are careful, that’s about the right amount to allow for waste on most roofs. If you have roofers who work on a piecework basis, rounding also virtually eliminates all disputes over the size of the roof.
How to measure the roof: Step #4 – Calculate the area
When you have all the measurements you need, grab a calculator and calculate the square footage of each roof section.
No matter how complicated the roof is, you can divide it into a series of rectangles and triangles. From there, it’s just simple math. For rectangular sections, multiply the length times the width. For triangular sections, multiply the length times the width, divided by two.
It’s a good idea to number each section so you don’t forget any. Then simply add up all the sections to get the total square footage. Dividing the total by 100 gives you the number of roofing “squares” to order.
To calculate how many shingles you’ll need for your starter course, simply add up the linear feet at the eave and divide by the length of one shingle. However, don’t cut all your starters at the beginning of the job. As you shingle each section, you may be able to use what you cut from the top course for the footings of the next section.
For your hip and ridge, you can choose from pre-cut shingle packages or cut your own from tri-tab shingles. Either way is fine, but not everyone has the same coverage. The pre-cut type will have the coverage printed on the package. A standard three-tab shingle package will cover approximately 33 linear feet of hip or ridge.
How to Measure the Roof: Step #5 – Order Your Materials
Please note that some shingles are packaged in three packages per square, while others are packaged in four (or more) packages per square.
Rarely will you calculate the EXACT amount of roofing you need for the job. Having a little to spare is often preferable to not having enough to get the job done. But try to keep some packages out of the weather in case you need to return them. Suppliers may charge you a restocking fee, but they don’t mind returning them as long as the packages are in good condition and you still have your receipt.