The following was provided to us by the Dicor Corporation
If the sealant around your roof edges, skylights and the like is looking cracked, brittle, loose or turned up at the edges, some repair and replacement is in order.
Staying on top of your sealant situation is one of the most vital maintenance steps for preventing leaks. It will also keep your repairs, when they are needed, fairly simple. If the repair area simply needs a good cleaning and removal of some loose material, your work should go fairly rapidly depending on the size of the affected area. If the sealant is too far gone, there may be more work involved in getting some of the old sealant off before resealing. Oftentimes you can simply apply the new lap sealant over the old cracked sealant.
Know what kind of sealant is right for you and your job. Dicor Products’ lap sealants include formulations that are self-leveling for horizontal surfaces, including self-leveling sealant that is free of hazardous airborne pollutants (HAPS), and non-sag sealant for vertical surfaces. Dicor Products added Ultra Sealant beginning in 2011 for the then-new kind of TPO roofing.