One of the most common questions we are asked is if one can roof of there current roofing system. While it may save you a few dollars in the beginning, many times this is not always the best options for the longevity of your home. A roof is made of multiple layers. First, there is plywood laid on top of the roof joists, then roofing felts, followed by either shingle or tile or layered asphalt and tar (for some flat roofs). There is also flashing and caulking, which seals edges around areas such as the chimney and roof vents. Eventually, these various points in the system can begin to fail. Flashing can come loose or the shingles can begin to degrade, allowing water to penetrate under the shingles, under the roofing felt, and eventually causing rot and damage to the plywood, even the joists. Leaks of various degree can occur as a result of any of these compromised areas.
Sometimes, problems like these are isolated to only a small section of the roof, and can be repaired. Other times, the entire roof needs to be redone. This leads many building owners to wonder if simply adding more roofing material (new shingles, more asphalt and tar, or metal roofing) on top of their existing roof is a viable option.
Usually, building codes allow for up to two layers of shingles. Certainly, overlaying new roofing over a previous layer reduces labor and disposal costs, and is faster. This is an option, but only if the roof is being replaced as a precautionary measure, due to roof age. If the roof already has leaks, spongy areas, or flashing issues, then recovering with a new layer will only temporarily bandage these problems, leaving them to recur in the near future. In fact, many roofing professionals believe that recovering an existing roof, even one in good shape, decreases the life expectancy of the new shingles by up to twenty percent.
When a new roof is needed, the best option is to tear off the old system before installing a new one. This allows the miami roofing contractor to inspect the roof structure thoroughly, replacing known, as well as hidden damage such as rotten wood and truss work. As with most things in life, a roof is only as good as its foundation. To get the most for the money, it is best to tear off and start anew; you can then rest sure in the knowledge that your roof is in good shape, top to bottom, and ready to protect your building for the next 10, 20, even 30 years.