Abstract: A caulk application device for the installation of doorframes includes an adhesive mastic strip with at least one receptacle containing caulk affixed to the upper face thereof. The caulk receptacle may comprise two caulk-containing chambers separated by a seam of sufficient width to accept nails or staples. The device is applied to the subfloor within a rough opening, with the caulk receptacle aligned to the interior side and an opposite lip of the mastic protruding to the exterior. The ends are turned up at the corners of the rough opening. The device is secured to the subfloor by fasteners, preferably applied at the seam between caulk chambers. The caulk receptacle is opened, exposing the caulk, and the doorframe set in place, riding on the bed of caulk. The protruding lip of mastic is turned down over the exterior, and covered with siding or the like.