Historic Sheetrock? You betcha!

Last week when I saw Kaitlin’s post called “Old Sheetrock?” over on Preservation in Pink, I sent the link off as quick as a wink to a friend of mine down on the Coast who just loves old sheetrock. In fact, he would be an old sheetrock collector if only those pesky homeowners didn’t object so strongly to having chunks of their walls cut out. Anyway, he promptly sent me a couple of pictures of a picture of a sheetrock label taken in situ in a house in Waveland.

While Kaitlin’s label says “USG Sheetrock” (USG stands for U.S. Gypsum), the Waveland label is for Universal Gypsum and Lime Co.’s Gypsolite Wallboard, but as my friend notes (and he’s not at all a nerd for noticing this), both products seem to be based on the same manufacturing process first patented on July 11, 1912. That’s way earlier than I ever knew sheetrock existed.

Click on either picture to make it larger and more readable.

Mississippi played a role in the history and manufacture of gypsum board/sheetrock. According to a pretty detailed company history of U.S. Gypsum, U.S. Gypsum started diversifying in the late 1920s and bought up a manufacturing plant for insulating board at Greenville, Mississippi, in 1930 (I believe this plant still operates):

Avery [chairman of the board] took advantage of the company’s strong cash position at the beginning of the Depression to purchase nearly a dozen building material firms weakened by the economic downturn. In 1930 US Gypsum bought into the insulation board business with the purchase of the Greenville Insulating Board Corporation of Greenville, Mississippi. Also in 1930, it bought into the metal-lath business with the purchase of the Youngstown Pressed Steel Company of Warren, Ohio, and the metal-lath division of Northwestern Expanded Metal Company. Avery also made US Gypsum, which had already been in the lime business for 15 years, a leading lime producer in 1930 with the acquisition of lime-producing firms such as the Farnam Cheshire Lime Company. Producers of mineral wool and asphalt roofing acquired in 1933, and asbestos-cement siding acquired in 1937, rounded out the Depression-era acquisitions. The company countered the downturn in new construction by exploiting the remodeling and industrial markets.

The firm was apparently pretty secretive about their manufacturing process, because the 1931 Sanborn map for Greenville shows the plant property blank with the note that access was denied. On the 1951 update to the Sanborn, they show the buildings, but still note that access was denied and that the site plan is based on plans in the office.

1950 Sanborn map showing U.S. Gypsum plant in Greenville, Mississippi

Well this has been a pleasantly nerdy post for me, and I’ve learned alot, but it’s interesting to me that there doesn’t seem to be a good scholarly look at the sheetrock/gypsum industry and its effect on the history of building. Seems like a good thesis or at least a journal article.

Next, I need to rustle up pictures of rock-lath I seem to recall taking in Waveland–rock-lath is a gypsum material with small holes in it was used in place of wood lath and took a skim-coat of plaster. Unfortunately, rock-lath has the same problem as sheetrock, which is that it can’t take water like good ol’ plaster can, so the rock-lath I saw was all moldy from the flooding and was in the process of being torn out.

Add to FacebookAdd to NewsvineAdd to DiggAdd to Del.icio.usAdd to StumbleuponAdd to RedditAdd to BlinklistAdd to TwitterAdd to TechnoratiAdd to Furl



Categories: Architectural Research, Greenville

14 replies

  1. Yeah, nerdy maybe, but that was a fun post! I didn’t know that sheetrock was that old either!

    The house into which I just moved has been sheetrocked over the plaster– all of the trim is now flush with the walls which looks somewhat strange. It also makes picture-hanging somewhat difficult.

    Like

  2. You wrote, “rock-lath is a gypsum material with small holes in it was used in place of wood lath and took a skim-coat of plaster. ” That is exactly what is on the walls of my 1925-era house on Drummond Street in Vicksburg. The plaster is at least 1/2 inches thick, so the total wall thickness (above the studs) is about 1 inch. It has held up well over the years, but there are a few cracks that open up in exactly the same places every few years.

    Beware that this older sheet rock may have asbestos fibers. Don’t sand or drill it.

    Like

  3. With holes on 4 inch square centres you don’t end up with as many keys as you do with wood or metal lath. Combined that with the fact that the plaster does not bind to the rock lath’s paper cover and you end up with a top coat that can fall off without much warning.

    Rock lath might have worked better with more holes, but then you begin to compromise the integrity of the board.

    Great post Mr. Malvaney!

    Like

  4. Thanks Mr. Rosell, and welcome to MissPres! That’s a good insight into the problems of rock-lath. It seems like it was a good idea except maybe in practice.

    Like

  5. i would like to know what a 1930/1940 lathe would be worth 32″swing appr.20ft long.it has cinncinati ohio the american tool co.21115 wrote on it. its a very large old lathe in running condition.

    Like

  6. “Unfortunately, rock-lath has the same problem as sheetrock, which is that it can’t take water like good ol’ plaster can, so the rock-lath I saw was all moldy from the flooding and was in the process of being torn out.”

    From my experience, moderate water leaks are harder on plaster (which turns into a pile of chalk and sand) than drywall (which can actually get sopping wet then regain most of its original strength when it dries, especially if the water can drain through the nail holes). Rock-lathe plaster is somewhere in between; it either survives with almost no damage, or it falls apart. Chronic low-level moisture is probably where real plaster has an edge, since the wood lathe is much less susceptible to mold. I’m not very familiar with the effects of flooding and I hope it stays that way. Maybe the “mold proof drywall” they have pushed on and off will prove to live up to its promise; it would be a bit closer to the best of all worlds.

    Thanks for the cool article!

    Like

    • Was the damaged plaster gypsum or lime based? If continuously exposed to water Gypsum mineral will dissolve. For hydrated lime to dissolve in water it would have to be exposed to an extreme amount of heat.

      I think both blue and green boards mold resistant clams are based on the chemical treatment of the paper binding the material rather than the gypsum itself. Since I think the manufacturing process is an industry secret I haven’t been able to find out.

      Some times in a situation where plaster appears to be molding on the surface, its really the residue paste of removed wallpaper that the spores are feasting upon.

      I never thought I would have so much fun discussing Sheetrock.

      Like

  7. I’m adopting a wait and see attitude about “mold-proof drywall.” I still expect it to develop some more-horrible problem, like kids who lick it grow up with mental problems, but maybe that’s just because I’m a pessimist :-)

    As for your point about holding up better in moderate water leaks, I’m afraid my only experience with rock-lath is on the Coast after Katrina, so combined perhaps we have a full experience with the stuff. The house I saw that had the rock lath had taken about 4 feet of water in the storm surge (not sitting flood water, but a surge that went in and then out again a few hours later). You could tell exactly how high the water had been because below was completely black and above was just fine. Meanwhile the plaster walls on regular wood lath had no mold at all, unless they had been locked up tight with wet furniture and such.

    Like

  8. Does anyone know anything about sheetrock used in 1950s houses that was installed in rectangles (about 2′ x 3′)?

    Like

    • That does strike me as familiar. Some early sheet gypsum products were smaller in size I understand so they could be handled by one person.

      Like

    • Upon further reflection your gypsum panels might be 32″ x 48″ as the panels were generally made to fit the 16″ on center standard. I think its about time for another post on gypsum lath and wall board!

      Like

    • What you might have is a gypsum plaster board as opposed to a “Sheetrock” or gypsum wall board. Gypsum plaster board is a solid 32″x36″ panel that is 3/8″ thick and engineered to accept plaster. Gypsum wall board is essentially the same but just produced in larger sheets and comes from the factory ready for paint or paper.

      Like

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: