Likely, yes. Removing your existing roof adds more work and time to the process, but it’s important to ensure the structural integrity of the building. Laying down new materials over an old roof can put too much weight on the roof itself. If you don’t take the time to remove the old roof, you may end up simply covering up surface issues rather than replacing them. The only exception to this may be a metal roof, which can be installed directly on top of other materials.