The ventilation shaft is constructed of metal studs. It is long and hangs from only one side. The idea is that the drywall will reinforce the structure and keep it from sagging. Right now it flexes when pulled down.
Our friend Mike suggested we use corner shelf brackets to reinforce the shaft. It is an inexpensive idea and will not be visible from the outside after the drywall is installed. So I ordered shelf brackets from ebay for about $1 each and I’m installing them inside the ventilation shaft.
I’m placing these every two or three feet along the shaft. They are reasonably easy to install. Either screwed into the rear metal stud or into the roof framing. When in the roof framing I have to drill new holes in the bracket a bit below the existing holes in order to hit the wooden cross beam.
With the braces in place the shaft still flexes a little but not nearly as much as it did.
The long shaft in the living room measures about 30 ft. and some of the metal studs are 24″ OC and some under the windows are 16″ OC. The shorter shaft is in the family room and it is about 15′ long. It is all 16″ OC. so it flexes less. I’m temped to skip the braces on this side. I can always use them for shelves later. I’m just worried we won’t get everything done by drywall day!