A seam sealing applicator for dispensing chemical sealant into seams between adjacent sheets of flooring is comprised of a sealant reservoir mounted atop an improved seam sealer applicator tip. The applicator tip of the invention has an elongated, hollow, rigid plastic body with a pair of laterally projecting wings or flanges between its proximal end which receives the sealant reservoir and its opposite, distal sealant dispensing end. The distal end of the plastic body terminates in a flat face, preferably oriented at an angle of about seventy degrees relative to the alignment of the linear sealant delivery duct formed within the body. A thin, hollow, narrow metal insert is set into the distal end of the body. A keel or fin portion of the metal insert protrudes beyond the flat face and projects into a seam between adjacent sheets of flooring. The fin portion of the metal insert defines a thin, narrow, dispensing slit through which sealant may be dispensed deep into the seam between sheets of adjacent flooring. A tracking sight ridge is preferably formed on the front of the applicator tip at the distal end thereof, directly above the flat sealant application flow face. The applicator tip body is at least three inches in length so that it can be gripped by the hand of the installer in a variety of different ways.