Overview
Detailed trim may offer only a narrow flat surface for the frame. Choose that fixing plane first. The measurements must describe the usable band, not a decorative ridge that cannot support the frame evenly.
Why Decorative Architraves Are Different
Raised and recessed trim does not provide one continuous mounting plane. If its outer edge is flat and suitable, use the standard face-fit architrave method. If not, the following method measures within a selected flat band rather than across the decorative peaks.
Step 1: Locate the Flat Mounting Surface
Find a continuous level band greater than 38 mm wide. It may be near the inside, centre or outside of the trim. Choose the same plane all the way around; do not use a rounded edge, groove or sloping face as the frame's fixing surface.
Step 2: Take the Measurements
Take three widths and three drops between matching boundaries of the selected flat band. Use the smallest width and smallest drop. If the band narrows, changes plane or is not greater than 38 mm, send detailed photographs so the mounting arrangement can be checked before ordering.
