Measuring Your Roof
How you measure a roof can be more complex than it first seems. Precise measurements of your roof mean that your roof replacement estimate will be accurate. An inaccurate measurement can result in a change in your cost or project timeline, and usually not in a good way.
A roofer will refer to the surface area of your roof in terms of squares. A square is equal to 100 square feet, which is a 10 foot by 10 foot area. This is an important calculation because the area of materials needed for your roofing estimate will be expressed in squares.
Simply put, area is calculated by:
- Multiplying the feet in length times the feet in height. The number you have will be the total square feet.
- Divide the total square footage by 100 to determine the number of squares.
This is pretty simple if you have a shed roof on a single plane. Roof measurements can be much more complex, however.
How To Measure A Roof
Generally, an professional estimator will get onto your roof to obtain accurate measurements. Precautions must be taken when getting onto your roof! Safety is important so use of anchors and specialized equipment should always be employed. Every time someone walks on your roof, there is also the possibility that they could fall or the roofing material is damaged.
If you plan to measure the roof yourself, it may be helpful to sketch a two-dimensional diagram of your roof from the ground. Be sure to include a drawing of each accessory and then document your measurements for each plane of your roof onto the sketch. If you are measuring from the ground, you’ll also need to factor in the slope, or pitch, of your roof.
Do not go on the roof unless you use appropriate safety measures and have someone watching you.
How to Calculate Roof Area
A careful accounting of each section of roof surface, called a plane or facet, is necessary for an accurate estimate.
As measurements are taken, keep in mind that every dormer facet also needs to be measured and added to the area, less the footprint of that dormer.
Measure the footprints of all dormers, pipes, chimneys, and skylights. These dimensions can be subtracted from the total area as you calculate the squares. The measurements of each of these features are important to track! Each of these roof features has additional considerations later when calculating the repair or replacement cost of your roof.
Keep in mind; every roof plane may not be in the shape of a rectangle or square. Each shape, whether it is a rectangle, square, trapezoid or rhombus, has a specific calculation to determine area. To more easily calculate the area, each facet can be separated into basic geometrical shapes. Be sure to keep track of each shape’s measurements and pitch.
Now, it is time to calculate the total area.
- Add up the square foot of each area measured.
- Deduct protrusions (skylights, dormers, vents, etc.).
- Take this total and divide by 100 to obtain the number of squares.
How did your roof measure up?
There May Be Other Factors
As you can see, knowing how to measure your roof will give you a better understanding of your costs to replace your roof. You can understand the importance of accurate measurements because it directly impacts the amount of material needed!
Your estimate from a roofing contractor should include this cost of roofing material needed for coverage (based on “squares”). That is just the start, however. Additional material is needed for any ridges, waterproofing the valleys, and so on. Depending on your roof type, different types of underlayment will need to be used. There’s a lot more that goes in to roofing costs than just what you can see.
Roofing issues can be stressful. Here at Legacy Roofing Northwest, we encourage our clients to be informed to reduce that stress.
Now that you understand the importance of accurate measurements, we’ll happily take care of that when you request an estimate within our service area. We have decades of experience and can do accurate estimates without risk or hurting yourself or damaging your roof! Call us at 425-444-ROOF today – you will see how we measure up.