At AWCI’s Industry Executives’ Conference & Committee Meetings, which was held last month in Miami, I encountered many questions and concerns from attendees. I do not think I have answers for all of them, but that can be the subject of future columns. (I always need to keep something in reserve just in case writer’s block sets in.)
The education program on BIM provided some answers about making the commitment to acquire BIM software, but it also gave some audience members quite a lot to think about. The panel members received high marks in the evaluations, and no one left before the program ended—that says a lot. I have not looked at the evaluations in detail, but I am sure that the comments will lead to future programs about BIM.
Another “hot topic” that came up was how to handle screws that do not engage the framing. I had received a question on this subject prior to leaving for Miami, but my research did not reveal any standards that addressed screw misses. I then spoke with Bob Wessel of the Gypsum Association, and he didn’t seem to think that holes from screws caused any loss of strength in the board.
Correcting the missed screws is not all that complex. First, remove the screws that missed and fill the holes with joint compound; if it is a fire-rated wall the holes must be filled with setting compound. The reason for removing the screws is that any vibration in the building structure will result in what could be called “nail pops,” where the head of the screw ruptures the joint compound resulting in a callback to correct the problem.
I know how easy it is to miss the framing, especially in the field of the board. A method to alleviate this problem is to snap lines on the face of the board. (I know: more work and loss of productivity.) If your crew hangs and tapes the board, this may not be a problem. If you are training new hangers you may want to give line-snapping a try to eliminate potential problems with missed screws. This is also an item you might want to preview with the owner and their QC representative so that they will not have undue expectations for the finished work.
Another area of similar concern was how to properly repair drywall. This could be in renovation work or in new work. Again, it is always advisable to review this with the owner and their QC representative. When dealing with the repair of fire-rated assemblies, the Gypsum Association’s publication GA-225, “Repair of Fire-rated Gypsum Panel Product Systems,” provides the necessary guidance for making repairs and maintaining the integrity of the fire rated assembly.
For regular non-rated partitions, ASTM C840, Standard Specification for Application and Finishing of Gypsum Board, offers some information on repairs. Paragraph 23.3.2 states the following: “23.3.2 Joint gaps not greater than 1⁄8 in. (3 mm) shall be prefilled with either ready-mix or setting type joint compound; joint gaps greater than 1⁄8 in. (3 mm) shall be prefilled with setting-type joint compound.
“23.3.3 Joint tape shall be applied as described in 22.214.171.124, 126.96.36.199, or 188.8.131.52.”
The three subparagraphs spell out what to do when using paper tape, self-adhering mesh tape and mesh tape.
This leads to the question: What is the greatest dimension possible when filling a joint gap under these specifications? It seems to me that the width of the tape would set the dimension since the tape is providing additional strength over the compound placed in the gap. That is, the gap would have to be smaller than the tape width for the tape to stick to the face paper of the gypsum panel.
Most, if not all, of the gypsum panel product manufacturers offer information and guidance in making repairs. National Gypsum states that the maximum diameter for repairing a hole is 2 1/2 inches. USG’s Gypsum Construction Handbook contains a chapter devoted to making repairs and contains details that might be of use. Of course, if the QC representative is just reading the book and does not exercise experience and judgment, you may have a problem.
This situation offers the potential to help the owner and the QC representative develop expectations of what the finished work will look like. We often discuss for benchmarking the work on a complex project, especially one involving a Level 5 finish. We often overlook the need for benchmarking other projects when we really should conduct some type of benchmarking to eliminate problems downstream. While this does involve added costs, just remember that in the benchmarking process you will generally be using field personnel, but when you end up in a dispute you are involving senior staff personnel and maybe even lawyers.
Donald E. Smith, CCS, is AWCI’s director of technical services. Send your questions to email@example.com, or call him directly at (703) 538.1611.