Fenestration unit with sash retention apparatus and methods

A fenestration unit comprising:

• a fenestration unit frame comprising a first side jamb and a second side jamb, wherein the first side jamb is connected to a first end of each of a head jamb and a sill, and wherein the second side jamb is connected to a second end of each of the head jamb and the sill;
• a movable sash retained in the fenestration unit frame, wherein the movable sash comprises a sash frame comprising a leading stile and a trailing stile, wherein the leading stile extends between a leading end of a head rail and a leading end of a sill rail and the trailing stile extends between a trailing end of a head rail and a trailing end of a sill rail, and wherein the movable sash is positioned in the fenestration unit frame and configured to move within the fenestration unit frame between the first side jamb and the second side jamb, wherein the movable sash is in a closed position in the fenestration unit frame when the leading stile is adjacent the first side jamb, and wherein the movable sash is in an open position in the fenestration unit frame when the leading stile is spaced apart from the first side jamb;
• and
• a sash retention apparatus comprising:
• a frame head component attached to the head jamb proximate the first side jamb such that the frame head component is located between the head rail and the head jamb when the movable sash is in the closed position, a sash head component attached to the sash frame, the sash head component located between the head rail and the head jamb proximate the leading end of the head rail, wherein, when the movable sash is in the closed position, the frame head component engages with the sash head component to form a first mechanical interlock between the frame head component and the sash head component such that the sash head component and the leading end of the head rail are restricted from moving away from the frame head component and the head jamb towards the sill, and wherein the first mechanical interlock between the frame head component and the sash head component restricts movement of the leading end of the head rail out of a plane defined by the fenestration unit frame,
• a frame sill component attached to the sill proximate the first side jamb such that the frame sill component is located between the sill rail and the sill proximate the first end of the head jamb when the movable sash is in the closed position,
• a sash sill component attached to the sash frame, the sash sill component located between the sill rail and the sill proximate the leading end of the sill, wherein, when the movable sash is in the closed position, the sash sill component engages with the frame sill component to form a second mechanical interlock between the sash sill component and the frame sill component such that the sash sill component and the leading end of the sill rail are restricted from moving away from the frame sill component and the sill towards the head jamb, and wherein the second mechanical interlock between the frame sill component and the sash sill component restricts movement of the leading end of the sill rail out of a plane defined by the fenestration unit frame;
• wherein the sash sill component disengages from the frame sill component when the movable sash moves from the closed position to the open position;
• wherein the sash head component disengages from the frame head component when the movable sash moves from the closed position to the open position;
• and
• wherein the sash sill component disengages from the frame sill component before the sash head component disengages from the frame head component when the movable sash moves from the closed position to the open position.