Spacer for retaining cladding element on structural building element

A spacer configured to retain a cladding element on a building element in a spaced apart relationship, the spacer having a spacer body comprising:

• first and second flange walls extending in parallel to each other and perpendicular to a fastener insertion axis,
• first and second side walls extending in parallel to each other and perpendicular to the fastener insertion axis, the first and second side walls integrally connecting the two flange walls to define an at least substantially hollow interior space that is open on both mutually-opposing sides in a direction, which is perpendicular to the fastener insertion axis and is parallel to the first and second side walls, the at least substantially hollow interior space being fully enclosed and having a constant cross section in a longitudinal direction thereof,
• at least one fastener insertion path defined in the interior space and being collinear with the fastener insertion axis, and
• a first plurality of protrusion ribs projecting from each of the first and second side walls into the interior space in a cantilever manner,
• wherein the protrusion ribs define a first predetermined width of the fastener insertion path,
• the first predetermined width is perpendicular to the fastener insertion axis, and
• the fastener insertion path is configured to widen to receive and squeeze a fastener having a second predetermined width that is greater than the first predetermined width.