Is it possible to lay new roof shingles over an existing layer? The short answer: Yes. There are plenty of reasons why homeowners would prefer to lay a new roof layer instead of replacing the entire roof. For instance, adding a new roof provides convenience and cost. Despite common belief, multiple layers of shingles do not equate to better waterproofing.
Advantages of Re-roofing
Most city building codes allow just two layers of asphalt shingles per roof. You cannot add a third layer.
Cost is the primary reason why homeowners opt for reroofing over an entirely new roof. Your typical 20-square reroof costs about $1,000 less than tearing off the old shingles and replacing them. Your savings go beyond just labor, though. With reroofing, you no longer require felt paper, which costs around $10 per square; plus, site and weather protection, cleanup, and more are nearly eliminated altogether.
- Less liability – Reroofing is typically less risky. There will be no hefty dumpster tearing up your lawn; property damage is minimized; and bare sheathing is never exposed.
- Quality – Shingle manufacturers honor their warranties, whether the shingles were used for reroofing or an entirely new roof.
On the other hand, adding new roofing shingles over an existing layer, while tempting, can be a potential downfall to anyone selling their home. The new owner will be stuck with the expense of tearing off two layers of shingles. However, reroofing will appear on the inspection roof. Many new homeowners do not want the hassle of multiple layers, and some may turn down your property because of the roof shingles in place. Consider this before reroofing. Sometimes, installing a new roof is the better option.