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Displaced Cladding

posted 3 Sep 2012, 08:17 by robert evans   [ updated 20 Sep 2012, 02:18 ]
A cladding system designed to accommodate differential movements between an aluminium frame and metal-faced insulation-cored cladding panels experienced gradual displacement of building components as the gaskets snaked their way along the grooves between shuffling panels.
The panels, being small, elongated less on heating than the relatively long frame sections. The connection between the two was a combination of shelf brackets and clamps, with polymer gaskets inserted tightly into grooves between the panels to complete the weather-sealing. Long continuous gaskets ran horizontally; vertical gaskets were shorter, and discontinuous at each horizontal joint.
When the system heated up and expanded, the panels and vertical gaskets tended to move upwards. When it cooled, the panels and gaskets contracted but did not uniformly return to their original positions. The consequence was a gradual displacement of parts of the system relative to one another. This opened gaps at the butt joints between horizontal and vertical gaskets and, in places, drove the vertical gaskets into the horizontal gaskets, deforming them. Those panels on the elevations which received most sunshine moved progressively out of alignment.
The design was intended, by avoidance of rigid fixings, to allow reciprocal movements without distress. But this lack of rigidity allowed each reciprocal movement to cause slight relative displacements in the panels and gaskets, the accumulation of which over time reduced weather resistance and marred appearance.
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