How To Install Roof Shingles Over Old Shingles

Shingling a shed and want some tips.

How to install roof shingles over old shingles. Do both sides first and then install ridge cap shingles over the top. To level out an existing asphalt shingle roof rip down reduce the height of two courses of shingles as shown in the drawing below. Leave the old valley flashing in place and install new over it. Step 3 cover the old shingles.

Attach with nails along the top edge of the strip. Do this on both sides of the roof. The felt should be secured every six inches with nails or staples. Mark 12 inches up on the roof for the first course of shingles then mark every 5 inches all the way up the roof to set your reveal.

The first row of shingles should overhang the drip edge of the roof. Damaged decking will need to be repaired before you can install any new shingles. Watch and see how easy it is. Damaged shingles should be removed to check the decking for problems.

If the job is done correctly with the new layer of shingles laid flat over the existing shingles the old roof cushions the new one and serves as a secondary barrier should wind or water ever break through the new shingles. Around an inch should do. Rip cut the starter strip or starter pieces so that they butt up against the second course of existing shingles and are even with the front edge of the existing roofing. Each shingle will require around 4 nails underneath the tar line and about half an inch under where the next shingle will overlap.

Many roofers recommend using laminated or dimensional shingles for re roofs because they re thicker than. To lay out the design for the shingles begin at the bottom of the roof and place a tape measure inch from the edge of the roof to ensure the shingles overhang the drip edge. All shingle manufacturers honor the warranty whether their products are used for a reroof or a new roof. Re roofers have tricks to lay new roof shingles over old so that the same step ups between courses are maintained but if any old shingles are cupped curled or otherwise misshapen those defects will telegraph through to the new layer.

Use a starter strip or cut pieces for a starter course.