Should I Re-roof Over the Old Roof?
Roof damage
Simple roofing problems can easily become bigger and more expensive problems if they are left unattended. For this reason the most effective way to prevent large repair bills to your roof is to have regular and thorough checks done. You can have a certified roof inspection done that will give you a two-year certificate. If anything goes wrong with your roof in this two-year period the roofing contractor who carried out the roofing inspection will repair the damages free of charge. By using a service similar to this problems can be identified early and rectified before they become uncontrollable and a new roof is required.

Roofs can become damaged even with proper and regular care
Despite your best efforts in having your roof regularly checked and maintained, however, there will come a time when you need a new roof. Whether this is because your old roof has become damaged beyond repair or simply because it is time for an upgrade, you should always use a professional to complete the work. They will know the best course of action for your particular requirements and will be able to advise you on the best type of roof and the best materials to use.
Hiring a professional
When it finally comes time to replace your existing roof it will always be necessary to tear down some of the existing roof and in many cases it will mean a complete tear down in order to start again. It is not a good idea to re-roof over old roof. It may be possible to save the insulation and the membrane, however, if there is any damage to either of these or if one or the other has become damp then it is prudent to have the whole thing replaced. If you do re-roof over old roof membrane or insulation that is damp this will not only make the existing roof that you leave in place ineffective but it will also have a knock on effect on the new roof that you place over the top. If you re-roof over old roof that is damp then the new materials you use will also become damp very quickly. This can create immediate damage or it may take several months of years to manifest itself. Either way you will have a roof with a diminished lifetime because you chose to re-roof over old roof that was already damaged.
How do I determine if it is safe to re-roof over old roof?
A professional roofing contractor should be brought in to fully inspect the roof you already have. They will be able to tell you quickly whether you can save the membrane or the insulation or whether you should replace everything. They will use non-destructive techniques to check for damp, meaning that if it is feasible to reuse existing roof parts they will not have become damaged during the testing process. It will also be necessary to have the insulation and the membrane certified, guaranteeing that it is safe to use again.
October, 2005
Copyright 2005 Roofer 911.com. All Rights Reserved
by Steven Briesemeister. Reprinted courtesy of Roofer 911.com, roofing contractor serving Long Island, Queens, Brooklyn, NY and northern Virginia.