Although it sounds like a good idea we can assure you the cons heavily outweigh the pros.
Roofing over existing shingle.
Let s start with the good.
How to do it remove caps.
Remove air vents and pipe flashings by prying out or unscrewing the fasteners holding the fixture.
You can save money because there s no dump fee for removing your old roofing and there s no need for additional felt paper over the old roof.
All shingle manufacturers honor the warranty whether their products are used for a reroof or a new roof.
That s also why building codes commonly limit re roofing to no more than two layers.
When you should tear off your roof and start from scratch instead.
1st and foremost your existing roof needs to be in reasonable shape.
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.
Why installing new shingles over old shingles can be good.
In fact the only pro to a shingle over is it s cheaper and cleaner.
Doing it now will make it easier to keep the reroofing job clean.
By placing metal roofing over shingles you can save in the labor costs of ripping them off while also preventing them from being thrown into landfills.
To shingle on top of existing shingles there are a few things you want to make sure.
Metal roofs over shingles will also provide an extra layer covering your home helping to further insulate it.
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.
Installing new roof shingles over old effectively doubles the weight of the roofing so you have to make sure your roof structure can handle the extra load.
Use a flat pry bar.
When roofing over your existing shingles can be a good idea.
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.
If you try to upgrade your 3 tab shingle to a dimensional shingle when nailing over it causes an aesthetic issue.
No missing shingles no gaps no holes in the roof no soft spots because of water damage.
Many arizona homeowners with shingle roofs do decide to roof over their existing shingles because.
The issue happens because 3 tab asphalt shingles run on a 5 inch exposure you see 5 inches of the shingle out of the full 12 inches while dimensional shingles run on 5 inch exposure.
A properly installed layover roof can look and function as well.
Advantages of metal roofs over shingles.
Disadvantages of metal roofs.
Remove the ridge caps.