Door sill frame assemblies and sliding door assemblies comprising the same are disclosed. In one embodiment, a sill frame assembly for a sliding door includes a first engaging surface capable of attaching with a sliding door and allowing lateral reciprocating motion of the sliding door and a second engaging surface, wherein along at least a first portion of the second engaging surface is attached a sill member and wherein along at least a second portion of the second engaging surface is attached a fixed-panel door, wherein the sill member includes a channel having a weather-strip extending upward from the channel, the weather-strip having a first open state for substantially preventing water and air intrusion past the sliding door when the sliding door is in a closed position and a second compact state for allowing accessibility of a wheelchair through an opening when the sliding door is in an open position.