A door sill assembly for an entryway of a building can include a substrate having a nosing and a sill channel. A nosing cover can be attached to the substrate and extending over at least a portion of the nosing and over at least a portion of the sill channel. A sill deck can be on the substrate. The sill deck can include a deck and a clip. The deck can be engaged with a portion of the nosing cover. The clip can be operably engaged with the deck. The clip can be removably attachable to the substrate. The sill deck is capable of removable attachment from the door sill assembly before or after the door sill assembly is installed in the entryway.