How to Replace Asphalt Shingles
Many homes in the United States have asphalt shingle roofs. Asphalt shingles are an attractive option when considering a roof system for your home for many reasons. Among these are appearance, expected life span, and cost. Another reason that makes asphalt shingles attractive to most homeowners is the ease of repair if minor damages occur. Before getting started, verify whether or not you have an existing warranty on your shingle roof system which may cover the materials, labor, or both.
Repairs to an asphalt shingle roof system require proper preparation for safety and completion of the repair. When working on shingles, you are working at elevated heights on roof slopes that may impact your ability to walk safely. If you are in doubt about your ability to safely complete the repair, please contact a roofing professional to complete the repair for you. If you are comfortable with labor-intensive home repairs, not afraid of heights or tall ladders, and you can safely use hand tools while balancing on a sloped surface, then you should feel confident to take on this project.
What You'll Need
Equipment / Tools
- Hammer (or nail gun)
- Flat pry bar
- Utility knife with a hook blade
- Extension ladder
- Caulk gun
- Shingles in quantity and style to match existing roof
- Roofing nails
- Asphalt mastic in a caulk tube
- Bungee cords or wire
Set Up the Ladder
If you are using an aluminum ladder, make sure that you are not setting it up near any power lines entering the home.
Set up your ladder so that it maintains a 4:1 ratio in the angle of the ladder. Make sure that the ladder has firm footing. Have someone hold the base of the ladder to prevent it from slipping out, if necessary. Tie the ladder to your home with bungee cords or wire to avoid slippage. (Drive extra nails into your roof to secure the cords or wire.)
Make sure you choose a ladder that extends a minimum of 3 feet above the edge of the roof.
What Is the 4:1 Ratio?
The base of your ladder should be placed one foot away from your house for every 4 feet of height you plan on climbing. For example, if you are climbing a 20-foot ladder, the base should be placed 5 feet away from the wall for safety and stability. In addition, avoid putting your weight on the top two rungs of any ladder or stability will diminish.
Remove the Damaged Shingle
Using a flat pry bar, break the sealant strips from around the area to be repaired. Slide the pry bar up and under the bottom edge of the shingle with gentle pressure to break the sealant strip free.
After the sealant strip has been separated, remove the nails from the damaged shingle. With the pry bar, remove nails from surrounding shingles to allow the new shingle to slide into place.
Assess and Fix the Roof Deck
After the original shingle and the nails have been removed, assess the area. If the deck or underlayment felt paper has been damaged it is recommended that these layers be repaired before installing new asphalt shingles.
To repair the roof deck, remove a sufficient amount of the shingles and underlayment to expose the surface of the plywood that spans a minimum of two rafters. Remove enough decking to allow a new piece of roof deck to attach to a minimum of two rafters.
After the deteriorated deck has been removed, install a new piece of deck that is comparable in thickness to the existing roof deck. Attach the decking to the rafters using nails (or screw-type fasteners) that provide sufficient penetration to secure the new deck to the rafters.
Replace the Damaged Underlayment
After repairing the deck, overlay the new deck with new underlayment. Attach the underlayment to the roof deck using staples or roofing nails.
Install New Shingles
After installing the underlayment, install the repair shingles. It may be necessary to cut the repair shingles to size with a utility knife if the damaged shingles were not full size.
Once the shingle has been cut to fit and laid in place, attach the shingles with the roofing nails. (Avoid nailing the shingle into the same hole that the prior shingle was nailed into.)
Make sure when placing nails that they will be under the tab of the shingle above. No nails should be exposed.
Refasten the Surrounding Shingles
Refasten the surrounding shingles where you may have removed nails to install the repair shingle.
Secure the Shingle Tabs
Insert a small bead of asphalt mastic below the tabs of the shingles for the new repair shingle as well as any other areas where the shingles were loosened. This mastic provides some attachment in place of the sealant strip.