When complete the canvas was applied to a wooden structure that was sheathed with 4 x 8 foot alumilite panels, (honeycomb plastic core with an enameled aluminum surface….sturdy but lightweight)  The seams are stress points, a tiny bit of motion of expanding and contracting in daily temperature rise and fall.  The panels flex a microscopic amount and the canvas and paint cracked a tiny bit.  This is to be expected and is considered normal maintenance.