My builder framed the joist opening, but wouldn’t install. Feared liability. I installed myself. Only comment is that I wish I instructions had been more clear about necessary clearance for Triebwerk mechanism. Telescoping ladders are great if you don't have much space to store a regular ladder. They can adjust https://atticliftsystems54320.blogripley.com/36141369/attic-lift-kit-eine-Übersicht