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.
Reroof over existing flat roof.
For now here are the most common reasons it might not be an option.
Reroofing is the process of layering one set of new shingles over a set of existing shingles.
This article series discusses best practices in the selection and installation of residential roofing.
Also the application of a new roof coating over an existing spray polyurethane foam spf roof system is permitted without removal of the existing spf roof system and any under lying roof system.
Beveled wood pieces called horsefeathers must be laid along the thick edges of the shakes to make a fairly flat surface.
Installing a new roof over an existing one also called a layover or nailover is often possible although not always the best option.
Because there is no tear off reroofing can go much faster and be much less expensive than a complete roof replacement.
Asphalt shingles can be laid over cedar shakes or shingles however this is a roofing project best left to pros.
Transmits roof loads directly to the building s structure and does not rely on the existing roof system s for support.
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.
There are a few situations where roofing over an existing roof just isn t possible.
Before you reshingle a roof read our step by step guide for adding new shingles over old ones.
It is the process where roofers install a new roof over your existing one i e.
This article discusses how to prepare an existing asphalt shingle roof for a roof over or for re roofing with new asphalt shingles.
Asphalt roof shingle re roofing advice.
We re happy to give you a free inspection.
The only way to know for sure whether it will work for you is to ask a professional roofer.
Roofing over your existing roof is not always possible.
All shingle manufacturers honor the warranty whether their products are used for a reroof or a new roof.
Add a new layer of shingles which means that there is no tearing off of the old roof.
It can only be done once so if you already have two layers of roofing in place reroofing is not an option for you.
If your roof is in good shape but has some damage to one side from a downed tree or has lost shingles in a wind storm an overlay is worth considering.
Nailing new shingles over existing ones is less expensive and faster requiring less labor but it also means you lose the chance to assess the sheathing for signs of water damage.
We also discuss proper asphalt shingle roof preparation for a roofover job.