Testing Confirms Significant Secondary Benefit Of Using Innovative Sub-purlin System To Facilitate Adding New Metal Roofs Over The Top Of Old

摘要

Adding additional dead loads to an existing roof support structure has been and continues to be a legitimate and prime concern of architects, engineers, specifiers and roof consultants whose professional careers are on-the-line by their recommendations. The introduction of the notched Z subpurlin in the mid'-90s made retrofitting so fast and easy that the practice rapidly accelerated as did the questions about added dead loads. It's obvious that the nesting design and secure structural connection that resulted therefrom added strength to the existing support system. The question was, how much?