ASTM Is Not the Code
ASTM is undoubtedly the most recognized leader in standard setting organizations. However, due to the vast global reach and an all encompassing array of standards, the organization is not perfect. I have great respect for ASTM history and for those actively involved on its committees. For those not familiar with ASTM International, it is a voluntary consensus standards organization that covers everything from making barbed wire, testing windows, galvanic coatings and installing plaster.
Today, ASTM has gained even more clout as the model building codes moved from a prescriptive-based code to a more of a performance-based reference code. This basically means that the code went from a “how-to-do-it” code to more of a “result-based” code. Since the code dropped much of the “how-to” language, the governing body needed a replacement. While ASTM is not perfect, it was and is the obvious and logical option available. ASTM is not the code; it is a standard referenced by the code, which does give it considerable credibility and clout.
I have been to only a handful of ASTM meetings in the last 30 years. I first encountered what I discovered as a potential problem back in the mid-1990s, when I was asked to sit in on the committee meeting for ASTM C-926. This is the standard for application of Portland cement based plaster. Being a plasterer, it was interesting to watch the industry experts review items, openly discuss and alter the items in the standard based on group discussions. I was merely a spectator when an item came up for removal from ASTM C 926.
To be specific, the committee was removing the sentence, “Dry rodding the surface of the brown coat shall be permitted.” There was virtually no discussion, commentary or objection. The vote was upon them and dry rodding was about to be dropped from ASTM. I felt compelled to speak up, so I asked why they were removing it. The answer was that the language was archaic and dated. I was a bit set back as I knew the exact opposite was true. I challenged them by asking, “Can you define dry rodding for me?” The room went silent. It was apparent they could not define the term; I asked if I would be allowed to provide an explanation of dry rodding to the committee. Permission was granted.
Dry rodding is not prevalent with hand tool application but very common with machine pumping of the cement brown coat in three-coat plaster work. When the cement plaster brown coat is applied with a plaster pump, this leveling is done with a darby or rod, as described by ASTM. A rod is a straightedge used to fill and level. A darby is similar to a rod but has handles. During this leveling step, it is common practice to leave the inside angles and other strategic areas filled with plaster (or what we call “a little fat”). The float follows along about 15 to 20 minutes later when the plaster is dryer but not set. Workers float the wall to promote densification of the brown coat, per Section 18.104.22.168. They also will use the rod to “cut” an inside angle and shave any imperfections off the “dry” wall surface. This is dry rodding. It is a good practice and should be allowed as an option to the plasterer.
Removing the language could allow a person to use a strict interpretation of the standard and forbid touching the wall with a rod after initial rodding is complete. Essentially, hand cuffing the contractor could result in lower quality workmanship, which would be detrimental to everyone. I must have explained it well enough as “dry rodding” was allowed to remain in C-926.
I was a bit surprised at the lack of experience in the room. I am not suggesting that plasterers run the room, but shouldn’t the committee have some practical tradesmen in the group? Today, the trend seems to move even further away from hands-on experience. Are we relying too much on test data and disregarding indisputable empirical evidence? Losing the practical hands-on knowledge in these groups in favor of special interest agendas is a shame and disservice. Not all plasterers are qualified to offer advice but an argument could be made that neither is every single person in these committees an industry or trade expert.
I have been on both sides of this fence—a tradesman and consultant. I suspect the market will ultimately decide the end results. Ironically, I look up section 22.214.171.124 in ASTM C 926 every so often, just to see if dry rodding has finally been dropped. I know one day it will be.