Installing Asphalt Shingles

If you want to save quite a bit of money, you can install your shingles—follow these steps to achieve a professional looking roof.

By replacing the shingles on your roof, you can help keep your house looking good and protect your family from the elements. In this article, you will learn the steps the experts take so that you can confidently install your asphalt shingles—preparing the roof, laying even rows, and installing ridge shingles.

Part 1 – Prepare the roof for shingles

1. Determining the number of shingles you’ll need. To cover about 100 square feet, you will need three bundles of shingles. Shingles are packaged in “bundles” that are sealed. Measure your roof and purchase the appropriate number of shingles for your particular job.

• To determine the area of your roof, measure the length and width of each section of your roof, then multiply. To get the correct square measurement, add each of the parts together, then divide by 100. This number divided by three will determine the amount of bundles you will need.

2. Figure the length of each shingle. You will need to figure out how many shingles you will need to cover the width of your roof. Most asphalt shingles measure 3 feet in length. You will have to use partial pieces of shingles on the end of each row if your roof’s width is not a multiple of the period of your shingles.

• The shingles on the bottom row will hang over the edge of the roof. You will need to cut the shingles on the edge so that you have a straight line for a wood shingle roof.

3. Old shingles and flashing will need to be removed. Begin removing shingles at the farthest peak from the area you want to dispose of the old shingles. Using the hammer method, use a roofing shovel or garden fork to remove the old shingles by hand—this will ensure the shingles will be removed completely. During this process, be sure to protect the sides of your house and windows—you can lean a large piece of plywood against the house underneath the area you are working—this will help avoid breaking windows or damaging the siding.

• Loosen the ridge caps and pry up the old nails. You may not get all the nails at this point—you will go back and remove the remaining nails later.
• The metal flashing around chimneys, vents, and valleys should be removed at this time. You will throw away most of the flashing, especially the flashing around the valleys—some may be worth saving, but it’s easier to just throw it all away.

4. Remove debris. Clean the roof as thoroughly as possible and remove any nails you were not able to remove in step 3. If there are loose boards in the sheathing, now is the time to reattach those. Replace or repair any boards that are rotted or damaged.
5. Installation of underlayment and flashing. Install asphalt, felt paper, or any special waterproofing you are using on your roof. It is recommended to use 15-pound roofing paper. Beginning at the lowest point of your roof, work upward stapling the felt down. Each row should overlap at least 3 inches. Be generous with the staples as you attach the paper to the roof deck, but be careful to not tear the paper. If your roof may be exposed to wind before you can install the shingles, use “tin caps” under the staples.
   • Anywhere ice dams or leaf and twig dams may build up or where the roof meets a wall, use sticky back ice and water shield as an underlayment. You may also use wide metal flashing in these areas.
   • New flashing should be installed. You will nail “drip edge,” a metal flashing, along the bottom edge of the roof deck near the gutters. The sides of your roof should have rake edge flashing. Flashing should be installed around the chimneys and walls—known as turn back flashing and step flashing.
6. Decide which starter row you need to use. You will either use pre-purchased narrow tables starter shingles or you will have to cut your own to fit your needs. Some people prefer to buy precut for the ease of installation, but others prefer to only buy one type of shingles and cut them to fit.
7. Make a guide for yourself with chalk. Beginning 7 inches from the bottom of the roof edge, make a chalk line, depending on the type of shingles you are using and your particular roof. Place the glue strip of the starter row along the drip edge and rake edges, whether you make a chalk line or not.
   • The chalk line should be seen directly above each row as a guideline, so mark from the left to right edge of the roof. Based on the width of the shingle, continue to chalk additional guidelines through at least four rows across the roof. Make sure the line on felt paper run in a square pattern, if you choose this method.

Part 2 – Three-Tab Shingles Installation

1. If necessary, cut your starter row shingles. Cut the tabs off for the bottom row of shingles if you are making your own starter shingles. Next, prepare the tabs and lay the starter row by shortening the first starter shingle by about half of one tab (6 inches). The glue strip should be placed at and along the drip edge and rake edges. You will shingle over the starter row to give the bottom row double thickness.
   • You want the entire shingle with tabs turned upward under your first row of shingles, so you should reverse the shingles on your starter row instead of cutting off all three tabs. Either way you do it, if you cut 6 inches off the length of the starter shingle and put the solid edge at the drip edge, you will prevent the slots between the tabs from lining up with the first regular row. This will keep you from exposing the asphalt roofing paper through the slots on the bottom row.
   • Nail the no-tab shingles and, with a caulk gun, apply asphalt cement in dots along the drip edge under the edge. Onto the line of asphalt cement dots, press the tab-less shingles down, leaving adequate spaces between the dots. If they are too close together, condensation or windblown water could become trapped under the roofing.
2. Cut different lengths of shingles for staggering slots. Cut several sizes of shingles from the three-tab variety you chose to make sure you have the correct sizes to lay your rows. To start the first row, cut off ½ tab-width of the first tab. In order to shift the slots of the singles on the row a ½ tab from aligning above and below the row, you will need each of these cuts. Do not throw away any scraps, especially single tab scraps—these can be used in the ridge cap shingles. The following cuts are needed:
   • ½ tab for the first row shingles
   • 1 full tab for the second-row shingles
   • 1 and ½ tabs for the third-row shingles
   • 2 full tabs for the fourth-row shingles
   • ½ of the final tab for the fifth-row shingles
   • The sixth-row tabs stay as is

3. Begin laying your rows. About six inches from its lower edge, nail the cutout shingle into place. About two inches from the end of each shingle, place one nail and then hammer another nail approximately one inch above each cutout. Be careful not to allow your nails to stick to the tar strip as you are working.
   • The shingles directly above should cover the nails by approximately one inch vertically. End nails will be covered up by about ½ a tab horizontally by the shingles above. These nails should be able to hold the top edge of the row of shingles directly below.
4. Place a full shingle against the cut shingles and nail into place. Alternating shingles across the roof, continue this pattern working right. Let your chalk line guide you to keep them straight.
   • Each shingle should have four nails and, to help resist wind, put six on the windward sides of the roof. In some cases, the code may require six on all sides.
5. When you reach the end of the row, cut the last shingle to the necessary size. It is ok to just let the excess hang off the end and then trim it after you have nailed it down. Repeat this process to row five, beginning the process with a full shingle and a chalk mark, just as you did on the first row. Continue this until you reach the ridge.
   • Allow about a tab width to overhang onto the next section of the roof if it is a hip roof, this will help strengthen the joint at the hip.

Part 3 – Ridge Shingle Installation

1. Install the last row. To make sure the roofing extends over the top of the ridge, bend the final row of shingles over the ridge and nail it to the other side. This will cover the nails and make sure no nails are exposed. If you are installing a ridge vent, do not do this. Today, almost all roofs have ridge venting, so the sheeting will need to stop short on each side. With a hook blade for cutting, your final shingle row should end here. Install continuous ridge vents or vented cap shingles to cover the ridge.
   • Bend shingles tabs or ridge shingles over the edge. To hold down the tab, put a bead of asphalt under the first ridge shingle at the end. Then, about an inch horizontally and vertically, nail so that the next ridge will cover the nails.
2. Ridge shingle installation process. Just as you did before, nail the shingles on both sides with the asphalt granules exposed across to the other end.
3. Apply asphalt cement. Where you removed the nail line, put dots of cement under and around the edge of the last ridge shingle. To the edge of the ridge, nail the four corners, making sure to add a dot of tar covering the nails heads.
   • To prevent water leaks, you should also add asphalt cement to the exposed nail heads on the last ridge shingle.