Should be a straight-forward question . . . :-)

I have to make a repair to two of the walls of my small studio, which were water damaged, along with a portion of the floor. All's been dried out, and my question is this: With regard to the walls: How to apply the normal rules of wall construction, specifically with regards to backing rod and caulking, when you are just making what amounts to a 'patch, and not a full wall build? Background: My studio - based on Gervais' book, and much of the knowledge on this forum, I have an 18 x 11 room, on a below-grade-level concrete slab. Walls are built as a two-leaf system of double 5/8 - GG drywall sandwiches, with air and insulation between. I track and mix in here, at modest levels - monitors have probably never been pushed past 90dB, and most of the time live at 80-85, or lower. The water caused the reclamation guy to cut out rectangles in two adjoining walls (both inner and outer) which meet at the rear corner of the room, near the entrance door. The cuts were made from the floor upwards about 18'', and are about 2 feet wide. I'll try to post a picture for clarity. My question is: Do I cut the patches to size with 1/4 inch gaps, and thus put backing rod and caulk around the entire perimeter of the repair job? Or do I cut the patches tighter, and join them tightly with just mud and tape, as if they were miniature-sized regular pieces of drywall, with no caulking? Knightfly's description here: http://www.johnlsayers.com/phpBB2/viewtopic.php?p=20003 and z60611's drawings right below that shows that normally, the seams of adjoining drywall get mud and tape but no backing rod. So, what do you think? I've searched, but couldn't find anything quite on point. If it's been covered, please point me to the thread. Thanks to all. bzb EDIT: Pics re-attached, per admin 12/30/2014:

As promised - pictures: Also, note - the exterior patch is the largest , closer to the dimensions stated. The interior patches are smaller, more like 8" tall, along the floor. Let me know what you think. bzb

Hi there "bzb1", and Welcome to the Forum! :) Unfortunately, the hosting service for the forum screwed up when they moved us to a new server last week, and they somehow managed to lose all photos that were uploaded between the 15th and 21st of December... including yours! So if possible, please could you upload those again. Just edit your post and re-insert the photos in the correct place. That should fix it! Sorry about the problem!!! :oops: - Stuart -

Thanks for the follow-up, and pics posted, as requested. Funny - I knew there was the problem when I originally posted, but when I log in, I can see the pictures I originally posted. Anyway, here they are again, and as admin, perhaps you can delete as necessary to save bandwidth. Thanks, again. bzb

I can see the pictures I originally posted.

Your first post is fine now: it's the second post from December 21 that has the missing pics. Can you see those too, when you are logged in? Very strange... the hosting provider really screwed up. Anyway...

I have to make a repair to two of the walls of my small studio, which were water damaged,

Bummer! Not a happy situation.

How to apply the normal rules of wall construction, specifically with regards to backing rod and caulking, when you are just making what amounts to a 'patch, and not a full wall build?

You'll need to cut the drywall back a bit further probably, so you can get enough space to put some cross-bracing in there, horizontally between the studs, to use as the nailing surface for the repairs. It doesn't look like you have enough space there to swing a hammer to get that in place. Once that is in place, then apply caulk liberally around the edge, nail the first layer of drywall in place, put in backer rod and caulk as needed, then do the second layer on top of that, also with backer rod and caulk. If this is the final finish surface of the room, then don't bring the caulk flush to the surface: leave it sunken, so you can mud and tape on top, then sand and paint as needed. If the joints won't be visible, then you can just leave the caulk overflowing liberally, all over. Yes, cut the drywall a little smaller than the actual hole, to allow for the backer rod and caulk. 1/4" might be too much, depending on the size of your backer rod: you want a sung fit, so the backer rod does a good job of sealing. The gap has to be small enough that you need to push the backer rod in, and here are no gaps or cracks around it once it is in place. But the important point is to get solid wood behind the joint, so you have something to nail/screw the drywall into. You can't just leave the joint floating over nothing. I also noticed that there's no insinuation in the wall cavity, so don't forget to put that in again, before you seal it up! Missing insulation can cost you a LOT of isolation. - Stuart -

Stuart - Thanks so much for your input. You've confirmed my intuition about how to make this repair, with one exception - I hadn't thought of doing the cross-bracing, and sadly, the contractor was in to complete the repair prior to receiving your reply. So the repair was done, in almost the exact way you describe, but for the bracing. Oh, well - we'll have to see how it works out without it. If needed, I can have this repair repaired at a later date . . . . While at work on this, I discovered I've got a bigger problem: the door which serves as the only entrance/exit to the room has warped awkwardly over the years, and there is now a 4" opening about 1/16" wide between the door and the seal around it through which all of our efforts to quiet the room are freely flowing :-( It's a solid core wood door set into a steel frame (town required - fire rules), and I'm afraid one of those door seal kits (e.g., http://www.acousticalsolutions.com/door-seal-kits) won't work, because of the curvature of the warp in the door. Any suggestions here? Thanks again, bzb

BTW: you were right to "insinuate" there was no "insulation", but that was temporary. We did replace the insinuation that was there before the water came and attacked us . . . :-) bzb