Picture Framing Around the Edges
When the perimeter of a sanded floor reads as a darker or lighter shade than the field, that's picture framing. It's a sanding pattern problem, not a finish problem.
What picture framing is
Stand at the doorway of a finished room and the floor has a visible rectangle around the perimeter -- often a darker or lighter shade, usually about the width of the edger pass. That's picture framing. The field looks one way and the edges look another.
Why it happens
Two different sanding patterns hitting the timber. The belt sander cuts in straight lines along the board direction. The edger cuts in tight circular arcs because it spins. Same grit, different scratch geometry. When you stain or topcoat, the two patterns absorb the finish at different rates and you see the boundary.
The fix during sanding
There are three reliable ways to blend the two zones:
Buffer the whole floor
Run a buffer with a fine screen over the entire floor after the final edger pass. This levels the scratch pattern across the whole surface. Bona FlexiSand 1.9 is the standard tool, with a maroon pad or fine screen. One pass over the whole floor and the boundary disappears.
Hand block the edges
On smaller jobs you can hand-sand the edge zone with the same grit you finished the field with. Slower than buffering but works on stairs and cabinetry where the buffer can't reach.
Step the edger up one grit
Some installers run the edger one grit finer than the belt -- so if the belt finishes at 100, the edger finishes at 120. This actually masks the boundary because the edger zone looks slightly tighter.
If it's already in the topcoat
Picture framing under a topcoat means screen-and-recoat at minimum. Buffer the whole floor with a fine screen, dust off, recoat. If the boundary still shows after the recoat, the underlying scratch pattern was too coarse to hide -- you'll need to sand back to bare and re-do the final grits.
Stop it on the next job
Always finish-buffer the whole floor before priming. It takes 20-30 minutes on an average room and prevents 90% of picture-framing callbacks. Use the same grit family on the belt and edger -- don't run a Bona Diamond on the edger if the belt was on a generic ceramic, the cut is too different.
Picture framing showing up?
Ring with the species, the grit you finished on, and whether you buffered. We'll talk you through whether it can be screen-and-recoated or needs a sand-back.
Call 1300 950 551