With concertina action the centre windows opens inwards on the outer window and the pair swing 180° to pack against the side wall.

Concertina folding windows are less prone to sag than their folding action counterparts as the jamb hinges are smaller & stronger. Hinge off hinge windows are suitable when it is imperative that the windows stack flat against the adjacent walls rather than at 90°.

Heavy duty stainless steel hinges used. Each hinged pair has one hinged handle.
Locking hardware and flush pulls included in price.

With folding action the centre window opens out over the outer window and the pair then swing 180° to park against the side wall.

Folding Action bifolds offer the flexibility of having the centre pair of windows open out independently for day to day use without having to operate the full bifold action. However they require flush hardware fittings and their larger obtrusive jamb hinges are more prone to sag.

Heavy duty stainless steel hinges used.
Locking hardware and flush pulls included in price.