Dap says its Dynaflex Ultra Advanced Exterior Sealant provides UV protection as well as dirt, water, mold, mildew, and algae resistance. Paintand rain-ready one hour after application, the sealant will not wash out or undergo rain damage, the company says, and paint that’s applied to the sealant after one hour will not crack, gloss, or dull. Dynaflex Ultra is available in five colors, and costs between $6.50 and $8. dap.com