They’re called “roof-over jobs” and they’re more common than you may think. In some areas, codes allow homeowners to install a new roof on top of an existing roof, but it’s not necessarily a good idea.
While it can save homeowners money, roof-overs don’t provide the same protection as a single roof where the previous roof has been completely removed. While many building
codes allow for up to two layers of asphalt roofing, for example, some homes may not be structured to handle the additional weight. All layers must be removed before a new roof system is installed, if weight is going to be an issue.
There are other concerns. Some manufacturers will not warranty a roof-over because the substrate may not be smooth, flat and clean enough. Insurers may also decline to either insure the roof-over or pay for roof damage if there are multiple layers.
If you’re buying a home with a multilayered roof, it’s difficult for structural inspectors to do a thorough inspection. This means fissures and leaks could be easily missed. Asphalt roof-overs also super-heat in the summer, which causes buckling that leads to leaks.
So what do you do if you’re buying a home that needs re-roofing? The home inspection should reveal any roofing issues, including layers. The inspector will tell you the building codes for roofs in your city and what your options are. If you’re buying in a community managed by a homeowner association, there may be additional restrictions on the type of materials you may use.
Ask your Berkshire Hathaway HomeServices real estate professional for more information.