How To Estimate Roof Size

You will need to express this size in terms of square feet.

How to estimate roof size.

To accurately calculate the area of your roof you must first determine its slope or pitch. If getting onto your roof isn t an option you can also estimate its size from the ground by measuring the area of the exterior walls and multiplying that number by the roof s slope. Steps method 1 of 2. The first step in a free roofing estimate is measuring the roof dimensions.

Roofs have one of three pitches. Don t use this as your only method of measuring. Low medium or high. To estimate roofing materials start by finding the total square footage of the roof and divide the number by 100 to determine the number of squares in the roof.

Keep in mind that the average size of a roof is 1 700 square feet so your total will likely be 10 higher or lower than this figure. A low pitch rises 3 inches every 12 inches of base horizontal length. Thus a moderate 6 in 12 roof pitch means that the roof rises 6 inches vertically for every 12 horizontal inches it runs. This is a rather complicated way to estimate a roof area and hardly suited to the diy fans.

Estimate the pitch of the roof. A roof s pitch is determined by how much it rises vertically for every foot it runs horizontally. Keep in mind that using google earth isn t going to give you a 100 percent accurate reading but it will give you a basic idea of the size of the roof for your calculations for the roofing materials. The roof area is simply 114x18x2 plus 30x18x2 giving 5184 square feet which is perfectly adequate for estimating materials.

Just use it as a starting point and you ll have a fairly basic idea of what you re dealing. To calculate the size of the roof you need to measure the size of the roof as if it were flat account for roof pitch calculate square footage and finally determine how many squares of material are required for the roof the calculator above can handle all of this simply enter the length width and pitch and it will determine the size of the roof in squares. From the diagrams there are two intersecting roofs measuring 114 feet and 30 feet at the eaves with equal rake of 18 feet.