![]() While unattractive, cracks in your ceiling usually aren't a cause for alarm, unless they accompany other problems, such as blackened drywall or a known leak. If your ceilings are plastered, cracks are often. Filling cracks with joint tape and filler, visit my blog here http:// good quality scrim here http:// settlement cracks over doors in new houses are. During a season when you are neither heating or airconditining do daily ambient temperature fluctuations cause the pops? What part of the country are you in? Is the roof a truss roof? Are there cracks in the walls? What is the.Repairing Historic Flat Plaster- Walls and Ceilings. Repairing Historic Flat Plaster- Walls. Ceilings. Marylee Mac. Donald Plaster in a historic building is like a family album. The handwriting. of the artisans, the taste of the original occupants, and the evolving. From. modest farmhouses to great buildings, regardless of the ethnic origins. A versatile material, plaster could be applied over brick, stone, half- timber. It provided a durable surface that was easy to. Plaster could be treated in any number of ways: it could receive stenciling. This variety and the adaptability. Fig. 1). Historic plaster may first appear so fraught with problems that its. But there are practical and. I have walls composed of gypsum lath covered by a base and finish coat of plaster but the finish coat is textured (rough segregate exposed). I have cracks in walls and ceilings. They way I would like to fix this is to remove. ![]() First, three- coat plaster is unmatched. It resists fire and reduces sound transmission. Next, replacing plaster is expensive. A building owner needs to think. Of more concern to preservationists. America's earlier craftsmen. Plaster can also serve as. A very popular question to DIYdoctor is 'how can I fix things to plasterboard walls?'. There are a variety of fixing available just for this but what you cannot do is use ordinary wall plugs. The wallplugs do expand as you. Plaster in a historic building is like a family album. The handwriting of the artisans, the taste of the original occupants, and the evolving styles of decoration are embodied in the fabric of the building. Preventing Blisters. The best way to cure this problem is to prevent it before it happens. Trying to fix the bubbling by scraping and patching immediately after it occurs will not work. You will have to wait a couple of weeks. Specialising in: Ceilings and Walls, Cracks, Cornice, Roses, Renovation, Fixing & Flushing, Painting, Gyprock, Ornate Restoration and Demolition using high quality products from Boral Plasterboard. For both reasons. Fig. 2). The approaches described in this Brief stress repairs using wet plaster. Dry wall. repairs are not included here, but have been written about extensively. Finally, this Brief describes a replacement option. Thus, a veneer plaster system. Veneer systems include a coat or coats. This system. is generally better suited to historic preservation projects than dry. To repair plaster, a building owner must often enlist the help of a. Plastering is a skilled craft, requiring years of training. Fig. 3). While minor repairs can be undertaken by building. Historical Background. Plasterers in North America have relied on two materials to create their. Until the end of the 1. Lime plaster was made from four ingredients: lime. The lime came from ground- and- heated limestone. Manufacturing changes at the end of the 1. Gypsum and lime plasters. Not only did the basic plastering material change, but the method of. In early America, the windows, doors, and all. Fig. 4). Generally the woodwork was prime- painted before plastering. Obtaining. a plumb, level wall, while working against built- up moldings, must have. But sometime in the first half of the 1. Installing these grounds so that they were level. Woodwork was then nailed to the "grounds". Fig. 5). Evidence of plaster behind trim. Lime Plaster When building a house. As the lime absorbed the water, heat was given off. When the heat diminished, and the lime and water were thoroughly mixed. When lime putty, sand, water, and animal hair were mixed, the mixture. This mixture was applied in. But the best plaster. The first two coats made up the coarse stuff. The finish plaster, called. Compared to the 3/8- inch- thick layers of the scratch and brown coats. Additives were used for various. For example, fine white sand was mixed in for a "float. This finish was popular in the early 1. If the plasterer. Or marble dust was added to create a hard- finish white coat. Finally, a little. Paris, or "gauged stuff," was often added to the finish plaster. Although lime plaster was used in this country until the early 1. A plastered wall could take more than a. In addition, bagged quick. Around. 1. 90. 0, gypsum began to be used as a plastering material. Gypsum Plaster Gypsum begins to. It sets in minutes and completely. Historically, gypsum made a more rigid plaster. However it is difficult to tell. Despite these desirable working characteristics, gypsum plaster was. Lime plasters had often been. They could survive occasional wind- driven moisture or water winking. Gypsum plaster needed protection from water. Furring. strips had to be used against masonry walls to create a dead air space. This prevented moisture transfer. In rehabilitation and restoration projects, one should rely on the plasterer's. In general, gypsum. Different types of aggregate. Today, if fiber is required. Lime putty, mixed with about 3. Lath Lath provided a means of holding. Wooden lath was nailed at right angles directly. Three types of lath can be found on historic buildings (Fig. Wood Lath. Wood lath is usually made up of narrow, thin strips of wood. The plasterer applies a slight pressure to push. The plaster slumps down on the inside. These keys hold the plaster in place. Metal Lath. Metal lath, patented in England in 1. United States toward the end of the 1. The. steel making up the metal lath contained many more spaces than wood lath. These spaces increased the number of keys; metal lath was. Rock Lath. A third lath system commonly used was rock lath (also called. In use as early as 1. Some rock. lath was textured or perforated to provide a key for wet plaster. A special. paper with gypsum crystals in it provides the key for rock lath used today. Rock lath was the most economical of the three lathing systems. Lathers. or carpenters could prepare a room more quickly. By the late 1. 93. Common Plaster Problems When plaster dries, it is a relatively rigid material which should last. However, there are conditions that cause plaster. Fig. 7). These include: Structural Problems Poor Workmanship Improper Curing Moisture Structural Problems Overloading. Stresses within a wall, or acting on the house as a whole, can create. Appearing as diagonal lines in a wall, stress cracks usually. Builders of now- historic houses had no codes to help them size the structural. The weight of the roof, the second and third stories. Even when houses were built properly, later remodeling. Occasionally, load- bearing. Deflection. or wood "creep" (deflection that occurs over time) can create cracks in. Overloading and structural movement (especially when combined with rotting. The plaster loses its key. When the mechanical bond with. If repairs are not. Settlement/Vibration. Cracks in walls can also result when houses settle. Houses built on clay soils are especially vulnerable. Many types of clay. In the dry season, water. During the. rainy season, the clay swells. Thus, a building can be riding on an unstable. Diagonal cracks running in opposite directions suggest that house. Similar symptoms occur when there is a nearby source of vibration- blasting. Lath movement. Horizontal cracks are often caused by lath movement. Because it absorbs moisture from the air, wood lath expands and contracts. This can cause cracks to appear year after. Cracks can also appear between rock lath panels. A nail holding. the edge of a piece of lath may rust or loosen, or structural movement. Heavy loads. in a storage area above a rock- lath ceiling can also cause ceiling cracks. Errors in initial building construction such as improper bracing, poor. Poor Workmanship In addition to. Poorly proportioned mix. The proper proportioning and mixing of materials. A bad mix can cause problems. Until recently, proportions. A plasterer may have skimped. Over sanding can cause the plaster to weaken or. Fig. 8). Plaster made from a poorly proportioned mix may be more. Incompatible base coats and finish coats. Use of perlite as an aggregate. Perlite is a lightweight aggregate used in the. It performs well in cold weather and has a. But if a smooth lime finish coat was. To prevent. this, a plasterer had to add fine silica sand or finely crushed perlite. Improper plaster application. The finish coat is subject to "chip cracking". Chip cracking looks. Another common problem is. Too much retardant. Retarding agents are added to slow down the rate. They have traditionally. If. the plasterer has used too much retardant, however, a gypsum plaster will. As a result, the. Inadequate plaster thickness. Plaster is applied in three coats over. In three- coat. work, the scratch coat and brown coat were sometimes applied on successive. Using rock lath allowed the. If a plasterer skimped on materials, the wall may not have sufficient. The minimum total thickness for plaster on gypsum board (rock lath) is. On metal lath the minimum thickness is 5/8 inch; and for. This minimum plaster thickness. Improper Curing Proper temperature. The ideal temperature for plaster to cure is between 5. Fahrenheit. However, historic houses were sometimes plastered before window. There was no way to control temperature and humidity. Dry outs, freezing, and sweat- routs. When temperatures were too hot. A plasterer would have to spray. If freezing occurred before. If the windows. were shut so that air could not circulate, the plaster was subject to. Since there is no cure for rotted plaster, the affected. Moisture Plaster applied to a masonry. When. salts from the masonry substrate come in contact with water, they migrate. The source of the moisture must be eliminated before replastering the. Sources of Water Damage. Moisture problems occur for several reasons. Interior plumbing leaks in older houses are common. Roofs may leak, causing. Gutters and downspouts may also leak, pouring rain water. In brick buildings, dampness at the foundation. Another common source of. When there is a paved area next to a masonry building. In both. cases water travels through the masonry and damages interior plaster. Coatings applied to the interior are not effective over the long run. The moisture problem must be stopped on the outside of the wall. Repairing Historic Plaster. Many of the problems described above may not be easy to remedy. If major structural problems are found to be the source of the plaster. Some repairs can. Minor. structural problems that will not endanger the building can generally. Cosmetic damages from minor building movement, holes, or bowed. However. it may be necessary to remove deteriorated plaster caused by rising damp. Repairs made to a wet base will. Canvassing Uneven Wall Surfaces. Uneven wall surfaces, caused by previous patching or by partial wallpaper. As long as the plaster is generally. Historically, canvassing covered. Filling Cracks Hairline cracks. They may be filled easily. Patching Materials, page 1. For cracks. that reopen with seasonal humidity change, a slightly different method. First the crack is widened slightly with a sharp, pointed tool. Then the crack is. For more persistent cracks, it may be necessary to bridge the. In this instance, a fiberglass mesh tape is pressed into. After the first application of a quick setting.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |