Lippert Alpha Systems 1021 Lap Sealant vs Dicor 501LSW-1 Lap Sealant

Both are white self-leveling lap sealants in 10.3 oz tubes, and both are proven on RV roofs. The Dicor 501LSW-1 is the safer default: it is the standard third part of Dicor's EPDM roofing system, skins over in about 5 minutes and is waterproof in about 4 hours. The Lippert Alpha 1021 is a solid low-VOC alternative that is paintable and rated 4.8 from 110 ratings, but it needs roughly 48 hours to cure and is aimed at flat horizontal surfaces only. Buy Dicor for EPDM or TPO roofs and faster weatherproofing; buy Alpha 1021 if low odor and paintability matter more.

• Choose the Lippert Alpha 1021 if you want a low-VOC, paintable sealant for a rubber, metal or fiberglass roof and can leave the patch alone for a couple of days.
• Choose the Dicor 501LSW-1 if you have an EPDM, Diflex II or Britek TPO roof and want the sealant that skins fast and waterproofs within hours.