System for plugging an opening, including: a plug element designed to cover said opening, a frame made up of at least four rails (1′) designed to be positioned inside the opening and including a first groove (22) formed on a front wall of each rail, and a seal (29),
said first groove (22) being designed to accommodate a substantially peripheral part (27) of the plug element, said seal (29) being designed to be accommodated with a tight fit in retaining means (34) inserted in said groove (22) and retaining said plug element on the frame.

A cornerlock is used with a frame assembly. The frame assembly includes first and second frame members each having walls defining interior voids. The cornerlock extends into the interior void of each of the first and second frame members. The cornerlock comprises first and second body members mating with the interior voids of the first and second frame members, respectively. Each body member has proximal and distal ends and are rigidly fixed to one another. The first body member has a leg and an arm both extending from the proximal end to the distal end. The leg is resistant to deflection. The arm is deflectable about the proximal end and immediately deflects upon engagement with the first frame member for engaging the leg with one of the plurality of walls and biasing the arm into engagement with another one of the plurality of walls of the first frame member.

A frame for a fenestration unit includes a corner member at a corner joint of first and second elongate frame members. The second elongate frame member includes a profile member and an elongate reinforcement beam disposed therein. The elongate reinforcement beam has a terminal end. The second elongate frame member further includes a corner reinforcement plug with an insert end that is received in the terminal end of the elongate reinforcement beam. The corner reinforcement plug also includes a corner end that is engaged with the corner member and an intermediate portion that is disposed between the insert end and the corner end. The corner reinforcement plug has a shoulder at a transition between the intermediate portion and the insert end, and the shoulder abuts against the terminal end. The intermediate portion is disposed within the interior of the profile member.

A frame for a fenestration unit includes a corner member at a corner joint of first and second elongate frame members. The second elongate frame member includes a profile member and an elongate reinforcement beam disposed therein. The elongate reinforcement beam has a terminal end. The second elongate frame member further includes a corner reinforcement plug with an insert end that is received in the terminal end of the elongate reinforcement beam. The corner reinforcement plug also includes a corner end that is engaged with the corner member and an intermediate portion that is disposed between the insert end and the corner end. The corner reinforcement plug has a shoulder at a transition between the intermediate portion and the insert end, and the shoulder abuts against the terminal end. The intermediate portion is disposed within the interior of the profile member.

A frame assembly with strengthened corners is described. The frame assembly includes internal corner sets that squeeze or pull mitered or angled edges of frame sections together. The corner sets fit into openings at corners between adjacent frame sections. The frame assembly includes corner braces that snap lock over a corner between adjacent frame sections. The corner braces fit over exterior surfaces of the frame sections forming the frame assembly. The corner brace snaps into grooves in the exterior surfaces of the frame sections. The frame assembly includes a corner member that engages to an outer flange of joining frame sections. The corner member spans the corner between the joining frame sections.

A window system has a window frame that surrounds a window unit. The window frame has a glazing leg with an outer wall and an inner wall. The inner wall forms a J-shaped stem, which forms a J-shaped channel between the inner wall and the outer wall. A first gasket engages with the outer wall, and is maintained in compression between the outer wall and the window unit. Likewise, a second gasket engages with the inner wall, and is maintained in compression between the inner wall and the window unit.

A frame assembly with strengthened corners is described. The frame assembly includes internal corner sets that squeeze or pull mitered or angled edges of frame sections together. The corner sets fit into openings at corners between adjacent frame sections. The frame assembly includes corner braces that snap lock over a corner between adjacent frame sections. The corner braces fit over exterior surfaces of the frame sections forming the frame assembly. The corner brace snaps into grooves in the exterior surfaces of the frame sections. The frame assembly includes a corner member that engages to an outer flange of joining frame sections. The corner member spans the corner between the joining frame sections.

A cornerlock is used with a frame assembly. The frame assembly includes first and second frame members each having walls defining interior voids. The cornerlock extends into the interior void of each of the first and second frame members. The cornerlock comprises first and second body members mating with the interior voids of the first and second frame members, respectively. Each body member has proximal and distal ends and are rigidly fixed to one another. The first body member has a leg and an arm both extending from the proximal end to the distal end. The leg is resistant to deflection. The arm is deflectable about the proximal end and immediately deflects upon engagement with the first frame member for engaging the leg with one of the plurality of walls and biasing the arm into engagement with another one of the plurality of walls of the first frame member.