A cupboard is what we ordered in our '09 Trillium
and Tom said, "Never again." He had such a hard time fitting a box in the space. But there again, I would think once you have the measurements, it would be just a matter of reproducing the first one. Which is one problem with custom work, the first one is always the hardest. You learn how to do it with the first one, and subsequent units are easier.
Frame the opening with 1x1, behind the FG, then screw the box into the frame from the inside.
Do you any other access to the space like through a drawer opening or easily removed sink, stove, etc?
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