Case Study: JP Cullen & Sons achieves perfect-fit prefabricated stairs and major schedule savings with Trimble

Wisconsin firm JP Cullen uses laser scanning to obtain highly accurate measurements on challenging projects

Wisconsin contractor JP Cullen was tasked with building a complex truncated spiral stair wrapped around a hexagonal shaft in a three-story Verona office building. The stair’s tight tolerances and irregular slab edges made accurate hand or theodolite measurements difficult and risked costly onsite fitting and schedule delays.

JP Cullen used Trimble TX5 laser scanners, Trimble RealWorks and Autodesk Revit to create a precise as-built 3D model: 10 scans (~2 hours) plus quick registration and modeling produced the fabrication-ready model in about half a day. Precision Metal Fab prefabricated each stair as a single piece and installed the staircase in three days with no rework—avoiding an estimated three extra weeks of onsite work and delivering higher quality and faster installation.

JP Cullen & Sons

Cameron Weinbrenner

BIM Manager