Dicor - Leveling Sealent vs Non

The self leveling will spread out somewhat from the bead that you apply from the tube. If you put a dab on a horizontal surface say the size of a dime, it will level out (flatten) to about the size of a quarter. This is so that when you apply it to a roof seam, it will spread out a s it settles and provide overlap coverage.
Lap sealant (non leveling) does not have the leveling agent and maintains the form of the bead that is applied from the tube. I have used non leveling on the roof when it was all I had and wanted tondona little touch up.
Steve