A few completed Replacement Portfolio projects by Parsons Roofing Company. Leaks on commercial flat roofs often inspire fear of an immediate replacement in the hearts and minds of property owners. Luckily, commercial roof replacements aren’t always necessary. There are many viable measures available that are less costly than replacement. Therefore, it’s very important to determine if a roof must be replaced before deciding to do so! However, a roof replacement will always be the ideal roofing solution for the longevity of your commercial roof and included roof warranties that vary per manufacturer, such as those offered by Carlisle and John Manville.