If your roof surface is in good condition and needs no roof repair, you can re-roof over the existing roof shingles. For best results, we recommend a technique in the roofing industry called nesting. However, it is advised that you check with your local building code on whether nesting is allowed to be done on your house or building.
When it comes to re-roofing there is a limit as to the amount of shingle layers your roof can have. In Canada, usually, only two layers of shingles are allowed because Canadian roofs are pelted with heavy loads of snow in the winter!
Another important thing to consider before deciding to nest is to make sure the existing shingle surface is flat. Installing shingles over existing brittle or extremely curled shingles can cause an uneven finish. This can create wide joints and poor alignment of your new shingles, which can limit the lifespan of the newly installed roof shingles.
Are you in doubt as to whether to replace your existing shingles or re-roof on top? Luso Roofing suggests you contact a reputable roofing contractor to come and assess your roof.