How do I scribe skirting to an uneven floor?
Scribing copies the floor's shape onto the board so it sits down tight along its whole length, instead of leaving a gap you have to fill.
- Difficulty
- intermediate
- Time
- 1 hr
- Read
- 3 min
Short answer
Hold the board level and in position, set a compass or a block to the widest gap, then run it along the floor with a pencil to transfer the floor's profile onto the board. Cut to that line with a slight back-bevel and the board drops onto the floor along its whole length.
The alternative to scribing is caulk, and on a genuinely uneven floor caulk means a bead thick enough to shrink, crack and look like exactly what it is. Scribing takes longer on the first board and much less time than you expect after that, and it is the difference between joinery and filling.
Step by step
- Find the highest point of the floor along the run.Stand the board in place and slide it along. The point where it sits highest is where the floor is highest, and that is the reference for everything else.
- Set the board at the height you want it to finish.Support it so its top edge is where it should end up — level, or following a datum line — with the largest gap under it somewhere along its length. Fix it temporarily so it cannot move.
- Set the compass to the widest gap.Open a pair of compasses, or take a block, to slightly more than the largest gap under the board. This setting must not change until the whole board is scribed.
- Run the compass along the floor with the point down.Keep the compass at a constant angle, point on the floor and pencil on the board, and draw it along the whole length. The pencil traces the floor's profile at a constant offset.
- Cut to the line, slightly on the waste side.A jigsaw for the shape, or a plane and a rasp for gentle curves. Follow the line rather than trying to improve it — it is already the right shape.
- Back-bevel the cut.Angle the cut slightly so the front edge of the board is the part that touches. That way only a knife-edge meets the floor and it beds down tight, rather than the full thickness fouling on a high spot.
- Offer it up and refine.Expect one or two adjustments on the first board. Mark where it is still holding off, take a little more, and try again. Do not force it down — that bows the board.
- Caulk the last hairline, if any.Scribing gets you to a fine line, not to nothing. A thin bead of caulk finishes it, and a thin bead behaves far better than a thick one.
Tips
- Scribe the boards that will be most visible and consider caulking the ones behind furniture. Effort where it shows.
- The same technique scribes a worktop to a wall or a shelf into an alcove — only the surface being copied changes.
Common mistakes
- Changing the compass setting partway along. — The offset must be constant or the transferred line is not the floor's shape. Set it once, to the widest gap, and lock it.
- Cutting square through the thickness. — The back edge then fouls on every high spot and holds the board off. A back-bevel means only the visible front edge has to fit.
Questions people ask
Can I scribe MDF skirting?
Yes, and it cuts very cleanly. Seal the cut edge afterwards, because bare MDF at floor level is exactly where a spill will find it.
What if the floor is going to be covered?
Then work to the finished floor level, not the subfloor, and consider whether the skirting should go on after the flooring instead. GuideHQ has a guide on that order.