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 Aggregat mechanism. DIY Attic Storage Assistance on Instructables.com The only way into the attic is pull down stairs. I remember https://jasperhpwch.nizarblog.com/35587608/attic-lift-dinge-zu-wissen-bevor-sie-kaufen