How to Measure the Finished Reveal on Roofing Shingles

Roofing shingles are much larger than the portion you see in a finished roof installation. More of the shingle is covered than the amount you see exposed and the overlap of several layers is what provides the protection from water penetration. The portion of the shingle that you can see is called the reveal and creates the decorative appearance of the roof. To determine the size of this reveal requires that you access the roof by climbing up a ladder, or by reaching through a window which is adjacent to the roof. With this information you will be able to estimate roof size without having to physically measure each section of roof.

Extension ladder
Tape Measure

Instructions

- 1
  Find the best access to reach the roof where you want to determine the shingle reveal, preferably the section of the roof that is closest to the ground. Pick a spot where the ground is somewhat level where the ladder will be placed.
- 2
  
  You do not need to climb onto the roof.
  
  Place the feet of the extension ladder on the ground so that the ladder will lean at a 15- to 20-degree angle when the top is placed against the eve and adjust the extension of the ladder so that the top will extend an additional 3 to 4 feet above the eve line. Use scrap wood if necessary to provide solid support and to level the feet of the ladder. If the ladder starts to lean sideways when you put weight on it put more blocking under the foot on that side.
- 3
  
  Not all reveals are uniform.
  
  Climb the ladder until you can reach the roof. From a position still standing on the ladder, locate a row of exposed shingle tabs nearby. Measure the distance from the bottom edge of one tab to the bottom edge of the tab immediately below. Check this measurement in several locations and if different, use an average of these measurements. For irregular tab shingles, pick a point that represents the middle of the shortest and the longest tabs and take your measurements from that point to determine the average reveal.
- 4
  Count the number of shingle courses in a section of the roof. Multiply the reveal by the number of courses, convert the result to feet, and you can determine the approximate vertical dimension of any section of roof on your house. You can measure the approximate width of the roof section from the ground and multiply these two numbers to get an estimate of how large the roofing area is and how much shingle material would be needed to re-shingle the roof. Remember that roofing is measured in "squares" which is 100 square feet of actual coverage area using a standard reveal.

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