Hi Pat, The I&P should have a positive crown. There have been some pianos produced in Europe that have reverse crown. An infamous one is the Rippen made in Ireland. Reverse crown occurs when the board shrinks enough for it to be pushed to far or when a section of the rasten (where the board is attached to the piano structure) has moved. On grands the belly rail is the weak point and on others the long side is too flexible. These condition cause a "rolled bridge" but is really a flattening of the board because of the movement of other case parts. In other words bridges do not roll but soundboards go flat. If a large section of the board is not glued well to the rasten you could loose crown. Best fix is likely springs between back post and rib to push it back into place. Otherwise a new board with corrected case structure. Newton
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