All roofing is a complete tear off of existing shingles. Any sheathing that needs to be replaced will be discussed with the home owner prior to replacing. I put one row of ice and water guard around the perimeter of the roof (two rows by request) and also in valleys and around any flashing areas such as chimney and tin shingles. I use a continuous ridge vent as well for the best ventilation for your attic.  Job site will be cleaned up and all debris will be removed. I use either Owens Corning or GAF shingles.  I do all the shingling myself no matter the size of the roof!