Preparing the substrate has always been the most important thing that contractors need to be concerned with because this includes adhering all seams / joints properly using non-metallic compatible sealants like '
DAP Polyurethane Construction Sealant' which comes in white, gray, and black. All seams/joints must be sealed before applying any coating. Some of these materials have very strong solvents which could soften or melt your joints if you do not prep the area properly by sealing all surfaces especially around air conditioning units, drain outlets and anywhere else where an opening penetrates through the sub-roofing system. This means that you will need to use '
DAP Touch 'N Foam' for all areas with a decent gap. It comes in Orange color, so you'll want to make sure you go over that with the polyurethane roof coating. Now we will move on to prepping surfaces: