When there are problems with a residential roof, one of three solutions is possible. It might be best to either repair, re-roof or replace it. Often, a repair will take care of a localized leak. If there’s just one layer of shingles on a roof that is in decent shape, re-roofing is an option.
If there are multiple layers of shingles on the roof, or if there is widespread damage to the sub-roofing, a full roof replacement is required. The crew tears off existing materials down to the sheathing. They repair any damage to the sub-roofing before installing the new roof.