Trimming errors
From the wallpaper problem solver - quick reference guide
Sometimes patterns will not match up properly from roll to roll or the seams will not butt because the rolls were incorrectly trimmed either at the factory or on the job.
The most common causes associated with edge trimming are:
- Overtrimming
- Undertrimming
- Scalloped edge
Under trim
Over trim
Overtrimming
Overtrimming is a result of too much of the selvage being trimmed away. When an excess amount of material has been trimmed away, there is no way to compensate for the missing pattern. If it is noticeable at a glance or is unacceptable, the installer should stop and return the wallcovering to the supplier for replacement.
Over trim
Undertrimming
Undertrimming is the complete opposite to overtrimming. Not enough of the selvage has been trimmed away, which results in a slight double image forming at the seam. This excess may be trimmed on the work table using a straight edge and cutter.
Under trim
Scolloped edge
Scalloped edge is the result of the trimmers in the factory moving back and forwards as the wallcovering is passing through. This results in the seams weaving in and out when they are supposed to be cut perfectly straight.
Note: The installer should identify this problem within the first roll hung; the remaining product should be returned for replacement.