Energy loss through the bottom of doors can be minimized with the installation of a door bottom in conjunction with your smooth top threshold. This combination provides a weatherproof seal between the bottom of the door and the top of the threshold. Drip caps also provide your exposed entry ways protection by diverting water away from the door bottom and thresholds. M-D Building Products offers multiple combinations of new and replacement door bottoms and drip caps that will fit most entry doors.