Practical Engineering: Support for Sagging Trusses

A business associate phoned me recently, concerned that her home office, located in a converted attic, seemed to be sinking into the garage below. I drove over, expecting to find some undersized, overloaded floor joists that I could fix with a simple beam underneath to take the springiness out of the floor. Instead, I found that the room had been created within the storage area of very large roof trusses. The floor was visibly — and disconcertingly — sagging under the weight of file cabinets and office equipment. Unintended Uses, Unforeseen Consequences Truss manufacturers commonly create a storage area within a truss by “boxing” out the middle section. These are referred to as attic or storage trusses, and are