Re-roofing a section:

Some roofs only have a section or small area that has trouble. It is possible to re-roof a section. When re-roofing a section a number of items must be considered. It is better to define the top end of a section at the peak of a slope so no future leaks from the older, higher area at the top of the slope flow into the newly roofed section. A barrier of sealant, wood and membrane can be built up to stop water flowing between old and new sections if necessary. If the deck is fluted metal the flutes may have to be foamed as well. Consideration should be given to the thickness of the replacement roofing – if the new roofing is higher or lower than the adjacent area people could trip or water could pond. Unless the waterproofing systems are the same then warrantees are rarely provided at the tie in’s to the older areas. Cutting out areas in asphalt based roofs generally causes damages on the adjacent “good” area edges. Traffic to re-roof one area can cause problems on the adjacent “good” areas as personnel and machinery cause cracks in asphalt roofing or damage to single-ply membrane or metal roofs. Sometimes the cost differences between roofing a smaller and a larger area are not that great due to the same fixed costs involved with roofing both areas – cranes, dumpsters, travel, meeting/supervision and warranties, so multiple prices should be requested from your roofing contractor.