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.
Roofing over old shingles.
How to shingle over existing shingles and how to shingle a roof how to install roof shingles shingle layout lines h.
Although many metal roof systems can be applied over an existing roof layovers are more commonly done with asphalt shingles.
Adding new roofing over old sometimes called a re roof is possible only with asphalt shingles also called composition shingles.
Damaged decking will need to be repaired before you can install any new shingles.
The felt should be secured every six inches with nails or staples.
Roofing second layer of shingles roofing.
All shingle manufacturers honor the warranty whether their products are used for a reroof or a new roof.
When contemplating a new roof many people hope to simply do a shingle over and avoid the extra cost and mess of tearing off the existing roof and starting from scratch.
Damaged shingles should be removed to check the decking for problems.
Install a layer of roofing felt over the roof before you begin installing the new shingles.
Step 3 cover the old shingles.
In this video i take show how to proper recover an old roof and make it look like it s a single layer check it out you might find useful tips for your new.
Beveled wood pieces called horsefeathers must be laid along the thick edges of the shakes to make a fairly flat surface.
But before we get started one thing must be clear.
Choose a shingle style with the same dimensions as those on your.
In fact the only pro to a shingle over is it s cheaper and cleaner.
Although it sounds like a good idea we can assure you the cons heavily outweigh the pros.