Q: When building with cold-formed steel framing and gypsum panels, does stud direction impact the finish and flatness of the completed work?
A: In a word, yes. It is important that the steel framing is installed with the stud webs or openings all facing the same direction, and it is just as important that the "leading edge” of each panel is first attached to the open side of the stud to ensure a uniform appearance. The following passages from the USG Construction Handbook explain: "To insure level surfaces at joints, arrange board application so that the leading edge of each board is attached to the open or unsupported edge of a steel stud flange. To do this, all studs must be placed so that their flanges point in the same direction. Board application is then planned to advance in the direction opposite to flange direction. When this simple procedure is followed, attachment of each board holds the stud flange at the joint in a rigid position for attachment of the following board.
"If the leading edge of gypsum board is attached to the web edge of a flange, the open edge of the flange can deflect under the pressure of attachment of the following gypsum board. Friction between the tightly abutted board edges can then cause them to bind, preventing return of the second board to the surface plane of the first. A stepped or uneven joint surface results.
"This recommended application procedure is absolutely essential for good results in steel-framed veneer and drywall assemblies.”
Similar language and a helpful image (below) are also found in section 8.2 of the Gypsum Association’s GA-216-13, Application and Finishing of Gypsum Panel Products: "To provide a more level surface at joints, arrange gypsum panel product application so that the leading edge of each panel product is attached to the open or unsupported edge of the steel stud flange.”
Q: We’re doing a framing job that we originally bid using 20-gauge non-structural materials. The general contractor has required us to change the material to 12-gauge structural material. He’s willing to pay the difference in the cost of the material, but he wants us to better justify the increased amount we’re asking for the labor, which is much more intensive for the new material versus the lighter material we originally bid on using. How can we make our case that we deserve the requested upcharge?
A: I would expect estimating software to be the quickest and most efficient way to show the correct difference in labor for installing light gauge non-structural framing versus heavier gauge structural framing. However, I don’t happen to have such a software package on my computer, and I suspect not everyone in the business does either.
So I contacted a few gurus I occasionally turn to when unusual steel framing questions arise, and it turns out that this is one of those maddening quirks of the building materials world that apparently has yet to be worked out. My contact explains that in order to project numbers for potential market share, the steel framing community has resorted to calculating the weight of the materials (I guess the light gauge member with a deep web weighs roughly what a heavier gauge member with a shallower web weighs when either one will do the job) in order to include both structural and non-structural materials in the desired projections. That’s fine for estimating materials, but it doesn’t get us much closer to the difference in labor for 12 gauge steel versus 20 gauge.
So, the best I could come up with was to compare the costs associated with the daily output of the two materials. I chose 3 5/8 inch studs in both gauges spaced at 16 inches on center. According to RS Means (2014), the total daily cost for one carpenter to install 20-gauge framing, including material and overhead, is $832.13 for 481 square feet of work. The total daily cost for two carpenters to install 12-gauge framing, including materials and overhead, is $1,961.00 for 74 linear feet of work. The labor rates for the two are $0.76 per square foot and $9.90 a linear foot. In both cases, that works out to almost $46 an hour for labor. The irony that follows is that the higher the wall, the more square feet installed. The default stud height in RS Means is 12 feet, and at that height, it’s almost a wash. My only suggestion beyond this is to time the same carpenter doing the same area using both gauges and extrapolate the total difference. I invite the estimators among the readership to weigh in on this.
Lee G. Jones is AWCI’s director of technical services. Send your questions to firstname.lastname@example.org, or call him directly at (703) 538.1611.