Many doors are sold with jambs but no flange, so a Jacksonville, Fla., contractor has developed a field-applied PVC flange. Zip Flash is simple to install: Run a bead of caulk down the back, then staple it to the jamb. It comes in 84- and 98-inch lengths for $7.50 and $8.50 respectively. A standard door needs 2 1/2 flanges. BAV Products, 904.321.6833, zipflashing.com