Structural elements for building construction and assemblies incorporating these elements

A structural assembly comprising a sub-frame structural element and a metal window frame element, said sub-frame structural element being adapted to be fitted and secured into an opening in a wall of a building around said window frame element and said window frame element being adapted to support at least one sash frame or glazing;

• said sub-frame element itself comprising a strip of corrosion-resistant liquid impermeable material of substantially constant cross-section throughout its length, said cross-section providing a substantially rectangular overall shape free from protrusions, providing the strip with two side faces and two edge faces, at least two parallel longitudinally extending grooves in one side face of said strip;
• an intermediate land on said one side face between each adjacent pair of said at least two grooves;
• two outer lands located respectively between each laterally outer groove of said at least two grooves and the adjacent edge face of said strip, said two outer lands being of unequal width;
• said window frame element having a longitudinally extending web and a flange depending from said web, said sub-frame element and said window frame element being secured to each other with the web supported by at least said intermediate land and said flange engaging with one of said edge faces, so that there is at least one of said grooves located under said web, and at least one of said grooves uncovered on the inside of said window frame element to provide a moisture channel, the unequal widths of said two outer lands permitting either of said outer lands to be on the outside of the assembly to accommodate window frame elements of different widths.