How to Install Roof Shingles Safely and Efficiently

The first thing to know about working on a roof is that it’s dangerous. While being on your roof for any reason carries the risk of falling off, performing a complex task such as installing roof shingles while on your roof divides your attention between accuracy and safety and increases the danger.

We highly recommend hiring a professional roofer for this project. However, if you choose to take on the job, exercise extreme caution during all steps.

Staying Safe

There are a few things you can do to keep yourself safe during a DIY roofing project.

• Know, understand, and follow all ladder safety guidelines.

• Know, understand, and follow all compressor and nail gun safety guidelines.

• Be aware of electrical hazards, including power lines and connections on your roof.

• Work in mild temperatures with no precipitation and stay hydrated. Take breaks often.

• Wear properly fitted and secured fall protection harnesses and ropes.

• Be sure to secure and maintain fall protection ropes at all times.

• Stop immediately if a task feels unsafe, and reconsider your plan before proceeding.

Start by measuring each roof section in square feet and add all the areas together to obtain the total square feet. The result represents how much shingle and underlayment material your project requires. Most types of shingles are available in “bundles,” which cover 33.3 square feet. Your supplier will likely ask for the number of “squares” your roof covers. A square of shingles covers 100 square feet, so each square equals three bundles.

You'll also need linear feet measurements for the ridge shingles that cover the roof's apex, starter shingles for the first row of material, and the drip edge that encircles the roof's perimeter. If necessary, add step and chimney flashing needs and flashing or boots for roof penetrations like intersecting walls, plumbing penetrations, or air vents.

Organizing your roofing project in detail will save time and frustration later in the process.

• Make a plan to locate the dumpster near the site but not directly under the roof. 

• Roofing materials are heavy and can be awkward to handle. Plan on having at least one other person on site and working with you to help carry and install materials. The extra person can also hold ladders and assist with tool organization.

• Ensure you have enough air compressor hose to reach all roof areas.

• Move patio furniture and other items from around the home. 

• Place several tarps below the work area to catch demolition debris and waste materials.

• Clear a convenient outdoor location to place new materials.

Use your measurements and plan to order the materials and supplies listed above. Add about 10% to 20% extra roofing materials to your order. Explain the precise drop-off locations to the dumpster provider and materials delivery supplier.

Most municipalities require you or your roofing company to obtain a building permit for roof replacements. Additionally, many locations require a special permit to place a dumpster in the street if that's your only option. Apply for and obtain the necessary permits for your project well before starting work.

Part of knowing how to install shingles is becoming familiar with the building codes related to roofing. Depending on the building code in your location, you may be able to leave one layer of shingles under a new one. However, in most cases, removing the existing shingles and replacing the underlayment is best when shingling a roof.

• Use a shingle stripper shovel tool to remove the majority of existing shingles and underlayment, starting at the ridge and prying them off as you work toward the eaves. Take extra care not to step on loose materials. Use a claw hammer to remove any nails left behind.  

• Remove the drip edge flashing around the perimeter, as it will get damaged in the shingle removal process. Also, remove any other flashing that suffers damage during the step. It's best to plan to replace all the roof flashing every time you replace your roof shingles.

Install the drip edge flashing by cutting it to the appropriate length with tin snips. Leave an additional inch of room, then cut the seam and fold back the side and top of the drip edge to create a cleaner look on your flashing. Secure the drip edge with roofing nails through its top flange and into the roof deck. Allow a 1/2-inch space between the lower drip edge flange and the existing fascia.

Install other roof flashings as appropriate for your roof, including penetration boots, chimney and skylight flashing, kick-outs, and valley protection flashing. Install step flashing as necessary, depending on your roof's specific needs.

Underlayment needs vary by climate, location, and the building code in your area. The most common type of underlayment for an asphalt shingle roof is roofing felt, which you can secure to the deck using plastic cap nails and a hammer. You can also opt for a more expensive ice and water shield, which has adhesive on the back and sticks directly to the roof deck. Extend the underlayment over your drip edge flashing on all sides of the roof. Always start at the bottom of a roof slope and work your way up.

Install the shingle starter strips at the roof's lowest edge using coil nails and an appropriate nail gun. Follow the manufacturer’s directions for the right nailing pattern, and extend the edge of the strips 1/2 inch past the drip edges on all sides of the slope. Continue along all the eaves to meet the building code and up each rake if you wish to provide additional weather protection. 

Snap a chalk line representing the top edge of the first row of shingles across the roof. Consult the manufacturer's nailing pattern requirements and your local building code for the correct number of nails per shingle in your location. Lay the first shingle in place on the chalk line and use your roofing nailer to secure it to the roof deck. 

• Install the next and subsequent shingles directly next to the first one before installing them all the way across the roof.

• Snap another chalk line representing the top edge of the next row of shingles. 

• Install the second and remaining rows, staggering the shingle edges by six inches from one row to the next. Use a utility knife to cut off excess shingles to line each row up.

• Continue to the roof's ridge. Overlap the roof apex with the top of the last row of shingles. Cut away material to accommodate the ridge vent if your home has that feature.

Center and bend ridge shingles over the top of each roof ridge. Nail them in place roughly one inch from the edge, depending on the shingle manufacturer's requirements, until you reach the end of the ridge. Cover any exposed roofing nails in the cap shingles with spots of roofing cement.