Cross-lining: why the liner is hung sideways on purpose

Cross-lining is one of the first techniques taught on a UK painting and decorating course, and to the untrained eye it looks like a mistake: the liner is run horizontally across the wall while finish coverings hang in vertical drops. Why run the liner the other way? The answer is seams. When a liner is hung vertically and the finish paper is then hung vertically over it, two sets of vertical joints run down the same wall, and sooner or later they will fall close together. A finish seam sitting directly on a liner seam has nothing solid under it, and that is where edges lift and gaps open. Turning the liner ninety degrees guarantees the two seam directions cross rather than run parallel, so every finish joint is backed by an unbroken sheet of liner.

This is called cross-lining, and it is standard practice before hanging a good-quality or delicate finish paper. The horizontal lengths are measured across the wall, pasted, and booked concertina-fashion so a long length is manageable on the wall. Joints between the horizontal lengths are butted, never overlapped, because an overlap leaves a ridge that will show straight through the finish paper once light rakes across it.

Cross-lining also lets a decorator hang the liner slightly off the finished ceiling and skirting lines. The top length is run a fraction below the ceiling and the bottom length a fraction above the skirting, so the liner does not have to be cut dead to those edges. The finish covering, hung vertically afterwards, is what gets trimmed cleanly to ceiling and skirting.

One detail decides whether the job holds: the liner must be bone dry before the finish paper goes on. A liner that is still giving off moisture will keep moving under the top layer, and the finish seams will open as the wall dries out. Cross-lining solves the seam-alignment problem, but only patient drying between the two stages makes the result last.