Scribe Baseboard to a Wavy Floor Instead of Hiding the Gap

The Problem

Set a straight baseboard on a real-world floor and daylight shows underneath — floors dip and hump, and the gaps telegraph every low spot. The usual cover-up is shoe molding, which works but adds a second trim line you may not want. The craftsman's answer is to make the baseboard's bottom edge match the floor.

The Technique

1. Stand the baseboard in place against the wall, resting on the high spots.
2. Find a small block slightly taller than the widest gap under the board.
3. Set a pencil on top of the block and slide the pair along the floor for the board's full length. The block follows every dip and rise, and the pencil draws the floor's exact profile onto the baseboard's face.
4. Cut to the line with a jigsaw set to roughly a 20-degree back bevel, leaving the pencil line intact. The back bevel means only the board's front edge will touch the floor, so the fit reads tight without needing the whole thickness to match.
5. Bring the edge the rest of the way to the line with a belt sander. Slow the sander down if you're new to it — the goal is kissing the line, not blowing past it.
6. Test the fit, touch up any spots that hold the board off the floor, and install.