Expert: Dan Griffin - 8/19/2008

Question
Hi, I live in Southern Florida and have a 22 x 22 garage that was converted to a family room. The ceiling was suspended and I tore it out. I would like to sheetrock the ceiling but I am confused on how to go about this. The roof is 2 x 6 's every 16" tied to a 22ft 2 x 6 ridgeboard.  Dead center going across the room the same direction as the rafters is a 23 ft 2 x 6 with plywood nailed from that to the ceiling (it is shaped like a triangle). This limits me from making the ceiling a cathedral, which i wanted . Should i just run 2 x 6's (2 14 ft nailed together) 22 ft and set them on top of the cinderblock walls. Do I need something bigger than 2 x 6, or can I use 2 x 4's since all that it will be holding is sheetrock? Do I need to nail into the existing rafters. I am concerned that the 22 foot span is to great and the ceiling will bow.

Answer
Brian,  if I am understanding correctly the outside walls are being held together by only one ceiling joist in a "cut roof" rafter system.  If this is true, that single joist is all that is holding the outside walls together stopping them from pushing out.  This in itself is unusual, as it would be normal to have one of these on every set of rafters.  I would not remove it without a builder or structural man seeing what is keeping the outside walls together.

I assume you object to the look of a drop ceiling, though I consider them quite normal and better than gyp for several reasons.  If you want to carry a gyp board ceiling you can nail it to the rafters though you should do some studying about insulating a cathedral and providing proper ventilation of the cathedral roof.  If that mid point chord is necessary, as I think it will be, you could encase it in drywall with a cathedral on each side.

It would also be possible to install a gyp grid system.  This is virtually identical to the drop ceiling grid, but the pieces are slightly wider, it is made for screwing drywall to the grid.