Installing Shingles over Old Shingles: 7 Tips
Installing shingles over old shingles is a possible roof replacement solution. Be sure to install the shingles over only one other layer. A third layer of shingles would be too heavy to be supported. Re-roofing over old shingles can save you time and money, since you will not have to rip off the old roof and pay to have it hauled away. You can install new shingles over your old roof if there
1 - Seeking Professional Advice
Contact your local government office to inquire about local codes regarding installing new shingles over old ones. Building codes in some area prevent this type of installation.
2 - Inspecting the Roof
Before you begin installing the new shingles, be sure to inspect the roof for any damage. Damaged shingles should be removed to check the decking for problems. Damaged decking will need to be repaired before you can install any new shingles.
3 - Covering the Old Shingles
Install a layer of roofing felt over the roof before you begin installing the new shingles. The felt should be secured every 6 inches with nails or staples. The layers of felt should be overlapped by 1 inch as you work toward the roof ridge. This will help keep any moisture from getting under the felt.
4 - Preparing for the Shingle Installation
Use chalk line to mark a center line down the roof from the ridge to the edge. Determine the number of shingles required to cover the roof along the edge Use a utility knife to remove the tabs from those shingles.
5 - Laying the Trimmed Shingles
The first shingle should be centered over the line you marked with chalk. The shingle should also hang about a quarter of an inch over the roof edge. Secure the shingle with nails, one inch from each corner. The next shingle should be placed and secured beside the first one. Continue until the first row of shingles is complete.
6 - Preparing For The Uncut Shingles
Position one of the uncut shingles on top of a trimmed shingle. The uncut shingle should hand a quarter of an inch over the roof edge. Mark the location of the top of the uncut shingle on the felt. Use the chalk line to mark the line at that spot across the roof. Continue marking lines every five inches up to the roof ridge. Use the chalk to mark vertical lines from the center to the outside edge of the roof at six inch intervals.
7 - Laying the Uncut Shingles
Position a shingle with the first horizontal line. Secure the shingle with four nails. Two nails should be placed an inch over the tabs. Two more nails should be placed 1 inch from the top. Continue until the first row of uncut shingles is complete. Position the first shingle of the second row with the second horizontal line. Nail the second row of shingles using the same process as the first row. Continue laying all the shingles, row by row, until you reach the ridge of the roof.