thereof may be configured generally as described with regard to fig1 insofar that each fascia expansion accommodation corner covering in the inventory of system 1600 having a substantially uniform nominal thickness 1653 of at least about 0 5 millimeters and at most about 5 millimeters over at least 80 of the area thereof e g may be configured to include a corresponding fascia expansion accommodation structure as shown in fig1 and first and second spacers 1421 1422 in use at least a single u201c first u201d fastener 1446 may hold the first spacer 1421 in contact with both a fascia expansion accommodation structure 1301 1602 1603 and the first joist a deck rim joist 1234 1434 as described above e g likewise a u201c second u201d fastener 1447 may hold the second spacer 1422 in contact with both the fascia expansion accommodation structure and the second joist a deck joist 1236 1436 as described above e g alternatively or additionally the respective first mounting layers 1542 and second mounting layers 1543 thereof may be configured generally as described with regard to fig1 insofar that each fascia expansion accommodation corner covering in the inventory having a substantially uniform nominal thickness 1653 of at least about 0 5 millimeters and at most about 5 millimeters over at least 80 of the area thereof e g may be affixed in use to the first and second joists each by a plurality of fascia board fasteners the first and second deck fascia boards each having a fastener non engagement aperture 1586 through which one or more gap spanning fasteners 1596 that support the fascia expansion accommodation corner covering pass one skilled in the art.