“A house is made of walls and beams;
a home is built with love and dreams.”
unknown
One of the oddest things about the end of the drywall installation was saying good-bye to the profusion of wires, pipes, vents, brackets, adhesive fillets, flitch plates, and the myriad of little things that we will never see again if we are lucky. Watching me looking at the drywall and hearing my comments on the job, one of the guys reminded me that in a few days this, too, will be completely hidden. There are many layers to completing a house, and this one was a “biggie.”
Our drywall company was Seabreeze Drywall owned by J.D. Crawford, who has been “hanging rock” on the Outer Banks for many years. There were some choices to make in the types of drywall used, with a few compromises along the way. For the generator room, the workshop, and the mechanical room, Type X was specified because of its fire resistance. (Type X paperless was used in the mechanical and generator rooms.) The presence of crystallized water makes all wallboard fire retardant to some degree, but Type X is formulated by adding glass fibers which increase the resistance to fires, especially once the hydrates are spent and the gypsum is left in powder form. Type C drywall is also fire resistant and considered to be a better choice than Type X, depending on the thickness of the board and other factors. Given our remote location, using Type C drywall throughout the house would have been a wonderful safeguard against fire. Because of our ceiling heights and the standard sizes of Type C drywall, that choice became cost prohibitive, leaving us with Type X in critical areas and standard drywall in most of the house. We also used paperless drywall in the bottom of the elevator shaft and purple XP drywall as an increased moisture barrier in the bathrooms. As a precaution against "pops" and for added wall strength, all of the drywall was glued and screwed.
Although I had heard stories about rough drywall guys, I found our two crews to be great folks. The first crew: Scrounge, Bubba, and Roland, came to cut and hang the “rock,” getting that big job done in just three days. That’s amazing, given the glue/screw appliaction, the size of the house and the height and angles of some of the ceilings. The second crew, Steve and Johnny, did the taping, mudding and sanding. Steve and Johnny are brothers who work well together and take tremendous pride in their craft. The impressive thing to me was that they both know a lot about the materials and the history of their trade. Steve explained to me that the bazooka, a mechanized tool that applies tape with “mud” and has a built in cutting tool, was originally made with left-over bazooka parts after World War II, hence the name and the appearance. When I asked Johnny if he knew anything about how long drywall had been used on the Outer Banks, he explained that a lot of knotty pine had been used through the years prior to drywall, because houses shifting in the winds and sand would cause plaster to crack. I wish that I had asked more questions, because this is a subject that is deeper than one might expect! Our specifications called for a Level 4 finish for drywall, which means that all joints and interior angles have tape embedded in joint compound, two separate coats of joint compound applied over all flat joints, and one separate coat of joint compound applied over interior angles. Fastener heads and accessories are covered with three separate coats of joint compound. All joint compound should be smooth and free of tool marks and ridges. It is recommended that the prepared surface be coated with a drywall primer prior to the application of final finishes. In our case, the painter will use a high solids primer prior to painting, which will complete this step for Level 4 and bring the finish up to a Level 5. Because the walls will have a slick finish rather than the textured “knock-down” finish common to this area, the extra care provided by Steve and Johnny will make a big difference.
The many uses of gypsum would make a terrific category on a game show for people who know a lot about unusual topics. Gypsum is used as fertilizer, a soil conditioner, as a binder for fast-dry tennis court clay, a tofu coagulant, a calcium supplement, blackboard chalk, an ingredient in Portland cement, a medicinal component in Chinese medicine, in foot creams, hair products, and is well-known for both plaster and drywall. Gypsum is an amazing and plentiful resource, but whose idea was it, anyway?
The word gypsum is derived from the Greek word meaning "chalk" or "plaster". Gypsum is a common mineral found in sedimentary rock formations in a crystalline form known as calcium sulfate dihydrate. Gypsum is found in layers that were formed under salt water millions of years ago before the water evaporated and left the mineral behind. The oldest traces of plaster renders (likenesses) are 9,000 years old and were found in Anatolia and Syria. Five thousand years ago, the Egyptians burnt gypsum in open-air fires, then crushed it into powder, and finally mixed this powder with water to make jointing material for the blocks of their monuments, such as the magnificent Cheops Pyramid. The ancient Egyptians also created models of plaster taken directly from the human body. Because gypsum from the quarries of the Montmartre district of Paris has long furnished gypsum used for various purposes, this material has been called plaster of Paris.In 1775, the prominent French chemist Antoine-Laurent Lavoisier discovered the chemical formula for gypsum: CaSO4,2H2O. The discovery that gypsum consists of calcium sulphate and crystalline water paved the way for the industrial processing of gypsum. Plaster results from the calcination of gypsum, which partially dehydrates to produce a hemi-hydrate (CaSO4 , ½ H2O).
Modern gypsum board has as its predecessor a product called “Sackett Board,” a composite material that was made of layers of thin plaster placed between four plies of wool felt paper. This board was patented in 1894 by Augustine Sackett, the man considered to be the grandfather of the gypsum board manufacturing industry. A sheet of Sackett Board was approximately 1/4 inch thick and 36 inches square. It had open edges, which tended to erode and the felt paper did not provide for a satisfactory wall finish. However, it was an excellent base for the application of gypsum plaster and it soon became a replacement for wooden slat lath in many places. To demonstrate the potential of gypsum plaster, the Alabaster Company used a mixture of gypsum plaster and fiber to finish the exterior of the 1893 Chicago World Columbian Exposition, thus filling the largest single order of gypsum plaster that had ever been completed to that date. In 1894, Sackett patented his manufacturing process for Sackett Board and opened several production facilities over the next eight years. By 1901, he was producing nearly 5 million square feet of board annually. Sensing the promise for the material, a group of small gypsum producers combined to form the United States Gypsum Company. By the end of 1902, the company had a total of 37 operations in the United States. In 1907, the Canadian Gypsum Company was formed, providing access to gypsum deposits in Nova Scotia.In 1909, Sackett sold his company to USG, where he served as a director until he died in 1914. In 1910, a process for wrapping the board edges was created, followed by the elimination of the two inner layers of felt paper, the replacement of the exterior felt facing with a paper-based covering, and the production of board in standard 4-foot widths. By 1916, Sackett Board had evolved into a ready-to-finish panel, and within a year, the production of the original product was discontinued. The demand for gypsum board accelerated during World War I. The first call-up of U.S. troops in 1917 created an urgent need for temporary military housing, both at home and overseas. The military used a variety of building materials to meet this need; however, a barracks fire led military specifiers to prefer gypsum board as a naturally fire-resistant material. Even so, wallboard use for residential housing was slow to gain popularity. After World War II, various industries seemed to simultaneously discover U.S. Gypsum Company and their amazing product, which they called "drywall" for obvious reasons. After the war, many builders were reluctant to return to the time consuming task of plastering walls, when the quicker completion of housing with the use of wallboard was more efficient and definitely more profitable…and homeowners liked it! Through the years, drywall has continued to evolve as the many uses and modifications of gypsum become apparent. From an inauspicious beginning as a basic building material, gypsum board has become the preferred interior finish material in North America. The ability of the basic gypsum mineral to adapt to a variety of circumstances has allowed it to be recast and reformulated over many centuries into a variety of different materials. Adaptive uses for gypsum are still being sought and its future as a building material remains bright. Very interesting!
