wall A
old wall ________________ edge of frame
new wall ________________| 
                         | Wall B

I recently floated a new wall over wall A which brought out the wall by about 3 1/2 inches. I am now about to put a second layer of drywall over wall B. Normally, you'd just screw the edge of the drywall into the frame of wall B, but, because wall A has come out further from the frame, I can't reach the edge of the frame so I can screw in the new drywall on wall B.

My first guess is to use a very long screw and drive it in diagonally so that it goes into the edge of the frame. However, do they make 4-5" drywall screws? I can't use adhesive on the drywall because I am using Green Glue between the layers. Green Glue is not so much an adhesive as is it a soundproofing compound. I've already installed the second layer and am just looking for a way to screw in the edge.

1 Answer 1


Unfortunately you are past the point where you could have installed a stud in that corner as a nailer. What you are saying is that you have unsupported drywall butting into the corner now. You certainly can try a longer screw, but be careful not to bend the drywall as the screw tightens. There is going to be a tendency for that corner to wave if you screw it to wall "B" diagonally. Can you still remove that piece of rock and put in even a small 1 1/2 X 1 1/2 nailer, then reinstall the drywall?

Regardless, use fiberglass tape in this corner if unsupported and the seam will have less tendency to crack. I can almost guarantee the corner will crack if you use paper tape.

I really think you should take the time to install a corner nailer now. It may take a couple of hours to fix the situation, but that is better than looking at a cracked, wavy corner after you have invested your time and money, knowing that you could have done right the first time.

  • 3
    I may have misunderstood your question. Are you installing a second layer of rock directly over a first secured layer of rock with no air gap? If so, use some PL200 or other good construction adhesive in that corner between layers. put a few screws in just to hold the two layers together until glue dries, then remove the screws before you mud it. Commented Dec 29, 2011 at 11:22
  • As I stated, I cannot use adhesive between the existing layer of drywall and new layer because I am using Green Glue. Also, to install a nailer, I'd have had to remove the existing layer. I wouldn't have had a problem doing that had I known I'd encounter this issue. The second layer is already installed, so there's no going back now. Idea: Shouldn't there be plywood on the outside of the house beneath the siding? If so, a long enough screw should clear the frame and secure into the plywood, right? Commented Dec 29, 2011 at 17:16
  • if you try to hit the outside sheathing, the long screw will probably grab the insulation on the way through and wind it up into a ball. Maybe try some butterfly anchors (toggle bolts) and tighten the screw enough to countersink it into the rock so you can mud over it. Commented Dec 29, 2011 at 19:14
  • 2
    Installing a nailer was the best solution. I took out a section of the wall spanning two studs, installed a nailer, and then reinstalled a double layer. I hated the fact that I wasted that Green Glue application, but it was only a small amount, I learned a valuable lesson, and I feel good about doing it right. Commented Jan 12, 2012 at 15:17

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