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Applying and Repairing Shingles

Whether you're replacing a few damaged shingles or starting a complete reroofing job, the following step-by-step instructions can make your project easier. Take a few minutes to read the instructions carefully before starting and you can save time, money and effort while completing a better job.


  • Working on any roof can be dangerous. You should take every safety precaution possible and always use extreme care while working on the roof.
  • Use common sense while working on the roof. Let someone know you are up there - or better yet, work with a helper.
  • Use a ladder that is high enough and strong enough for the job you are doing. Secure the ladder at the top and bottom before climbing it.
  • Use extreme caution when working near power lines, conduits or TV antennas. Never touch them or allow a metal ladder to come in contact with them.
  • Never start a roofing job in cold or wet weather. Also, allow early morning dew to disappear before beginning your work.
  • Wear heavy, rubber-soled shoes with a non-skid tread to prevent slips and avoid wearing loose clothing.
  • If the roof slopes more than a 6" rise for every 12" horizontally, use roof brackets and boards to provide extra footing support. Place all tools and shingles within easy reach and where they will not slide off the roof.
  • Keep the roof surface clean and free from loose nails and shingles. These can cause you to slip and fall.
  • Keep people away from below the area where you will be working.


  • Roofing shingles are sold in "squares." Most asphalt shingles are baled together with three or four bundles per square.
  • First, measure the length and width of each area of the roof. For each area of the roof, multiply the length times the width. Then add the results for the total square feet of shingles needed. Measure all dormers and extensions.
  • Divide the total square footage by 100 and purchase that many squares of shingles.
  • Purchase an additional 10 percent of the number of shingles for cutting, waste and starter courses and to save one bundle for future repairs.
  • You'll also need about 2-1/2 lbs. of roofing nails for each square of shingles. Use hot-dipped galvanized roofing nails, either 11- or 12-gauge with a 3/8" diameter head, or follow the shingle manufacturer's recommendation for the type of nails to be used.
  • Use 1-1/4" or 1-1/2" nails for new roofs, or 1-3/4" nails for reroofing or repairs.
  • If you are starting a new roofing job, or a complete reroofing project, you'll also need enough 15-lb. roofing felt to cover the entire roof area underneath the shingles.
  • You'll need roofing cement for edges, flashings and ridges.


  • There are many types, styles and sizes of asphalt shingles.
  • Your selection process should begin with the type and grade of asphalt shingle needed for the type of building. Some factors to consider are the purpose of the building, the slope of the roof, local weather conditions and the design, style and size of the structure.
  • The exposure for each type of shingle is usually specified by the manufacturer. However, for most common shingles, a 5" exposure is standard.


  • You can successfully lay asphalt shingles over any existing roof. However, if there are more than three layers of old roofing on the structure, they must be removed completely before applying new shingles.
  • Make any necessary repairs to the roof structure before beginning the reroofing project.
  • Drive down or remove any loose or protruding nails.
  • For reroofing jobs, renail any loose shingles and replace any missing shingles with new ones. (See the upcoming repair section).
  • If you're applying new shingles over old wooden shingles, nail them securely and use feathering strips for a smooth appearance.


  • Making repairs to an existing asphalt shingle roof is easy when you follow these step-by-step instructions.
  • Use a small pry bar to pull out the nails holding the damaged shingle. Remove both the nails and the shingle.
  • If you cannot reach the nails, use a sharp linoleum knife to cut away the damaged shingle.
  • Always try to replace the damaged shingle with one similar in weight, size and color.
  • Apply asphalt roofing cement to the back of the replacement shingle before putting it into place.
  • After positioning the new shingle, nail it down with 1-3/4" roofing nails.
  • Position the roofing nails so they are covered by the shingle above. For extra protection against leaks, apply a small amount of roofing cement to the nail heads.


  • roof valley is formed where two roofs join at an angle. You must be careful when shingling in this area - an improperly laid roof valley can easily develop leaks.
  • Valleys should be covered with a mineral-surfaced, roll roofing material (see image).
  • First, place an 18"-wide strip or metal flashing down the center of the valley, from the eaves to the top of the ridge.
  • Nail this material down on the outer edges only, making sure that it stays flat in the valley.
  • Place roofing cement along each edge.
  • Next, lay a 36"-wide strip of the roofing material down on top of the previous strip, and nail its outer edges.
  • Snap two chalk lines down the edge of the valley. Start at the ridge, with the lines centered in the valley and 6" apart. As you move down the roof, spread the lines apart, about 1/8" per foot, down to the eaves.
  • Now you're ready to apply shingles. Lay them down to the edge of the chalk lines, and cut them to fit (see image).
  • Place the end of each shingle in roofing cement to seal it before nailing it into position.
  • Do not nail shingles closer than 6" to the chalk lines.


  • Applying new asphalt shingles on a complete roofing job or on new construction requires a layer of 15-lb. roofing felt over 5/8" plywood sheathing.
  • Each course of the roofing felt should overlap the preceding course by at least 2" to provide adequate weatherproofing protection.
  • Staple the felt underlayment into position, starting at the edge of the eaves and extending up to the roof ridge.


  • First, locate the exact center of the roof and mark it with a chalk line.
  • Next, install a starter strip along the bottom edge of the roof. Many manufacturers offer a special starter strip; however, if you don't have this strip, you can cut the tabs off the shingles and use the shingles to form a starter strip. (see image)
  • The starter strip should project out over the eaves and the gable end by about 5/8".
  • After the starter strip is in place, again locate the exact center of the roof and mark it with a chalk line.
  • Center your first shingle on the chalk line-directly on top of the starter strip-and nail it into position (see image).
  • Use four nails in each shingle, located in the position shown in the image. Always drive the nails straight in and never at an angle, as they could cut the shingle and cause leaks.
  • Place the nails about 5-5/8" up from the bottom of the shingle.
  • Each succeeding shingle should bump up against the center shingle. Continue applying the shingles to the end of the roof in each direction (see image).


  • After the first course of shingles has been laid on top of the starter strip, snap down a chalk line at the manufacturer's specified exposure, usually 5", to aid in applying shingles.
  • Continue snapping down chalk lines until you reach the ridge of the roof. This simplifies the job of laying each succeeding course of shingles in a straight line.
  • Start the second course of shingles on top of the first course. Place the cut-out over the center of the middle tab on the center shingle.
  • Remember, a shingle cut-out must never fall directly over another cut-out in the row immediately below it.
  • Continue placing shingles in the second course to the end of the roof in each direction.
  • Start at the center of the roof for the third course of shingles. Again, place the cut-out over the center tab on the preceding row, and continue to the end of the roof.
  • Follow this procedure until you reach the ridge of the roof. Then start on the other side of the roof in the same way you started the first side.


  • The easiest way to finish around vent pipes is to purchase a vent pipe boot that slides down over the vent pipe. It consists of a rubber gasket and metal flashing. If you do not have a vent pipe boot, follow these directions.
  • Place mineral-surfaced roofing material or metal flashing around the vent pipe before laying any shingles.
  • Cut a square of flashing material with at least 6" of edge around the vent pipe (see image).
  • Cut a hole in the center of the flashing that's large enough to fit over the vent pipe. Coat the bottom side with roofing cement, slip it over the vent pipe and nail it into position.
  • Lay shingles up to the vent pipe, completely covering the edge of the flashing material. Set the ends of the shingles in roofing cement.
  • Cut a hole in the shingle that goes over the vent pipe, apply roofing cement to the bottom and nail it into position (see image).
  • Repeat the procedure on the next course of shingles if they, too, overlap the vent pipe.


  • Place mineral-surfaced roofing material or aluminum flashing around the edge of a chimney before shingles are positioned.
  • On older roofs, you can use the old flashings for a pattern. On new roofs, use this image as a guide for cutting the flashing.
  • Fit the new flashing around the base of the chimney, then cement and nail it into place.
  • Cut flashing strips into pieces measuring 7" x 10", then bend them in half to 7" x 5".
  • Place these flashing strips against the chimney, seal the edge with roofing cement and nail into place.
  • Apply shingles up to the edge of the chimney, seal the edge with roofing cement and nail the shingles near the edge of the flashings (see image).


  • Each course of shingles applied to the hip roof should be continued around the roof (see image).
  • Trim each shingle to the angle of the hip ridge.
  • Use regular hip shingles or cut standard shingles (three-cut)to cover the hip ridge.
  • Cover the hip ridge before the main roof ridge (see image).
  • Start at the eave and apply hip shingles at the same exposure as the main roof.
  • Use two shingles to start the run on the hip ridge (see image).
  • Use four nails per shingle and leave no nails exposed.
  • When placing the last hip shingle on the main ridge, seal it with roofing cement and nail it into position.
Carpenter's Apron#15 Felt Roofing
Ridge ShinglesAsphalt Roofing Cement
Copper or Aluminum Flashing MaterialSoft Soled Shoes
LevelCleanup Cloth
Roofing NailsChalk Line
#90 Mineral Surface RoofingTin Snips
LadderWork Gloves
Safety RopeHand Cleaner

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Check your state and local codes before starting any project. Follow all safety precautions. Information in this document has been furnished by the North American Retail Hardware Association (NRHA) and associated contributors. Every effort has been made to ensure accuracy and safety. Neither NRHA, any contributor nor the retailer can be held responsible for damages or injuries resulting from the use of the information in this document.

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