Pre-industrial plaster from the 1850s or earlier may be affected by shortcomings in the materials themselves, such as lime of uneven quality or sand that contains impurities. Historic plaster walls that have stood up well for decades can start to fail for a number of reasons. What we’ll explore here is an overview of these methods and materials to explain what’s possible with plaster repairs and how they can help you retain the solidity and beauty of three-coat plaster walls and ceilings. Though being handy comes into play here, too, repairs often gain as much from clever products specifically made to improve the results and assist the ad hoc plasterer. In contrast, flat plaster repairs are usually much smaller and more variable, with techniques adapted to the many kinds of damage and decay, from tiny cracks to large holes, and through hard-won experience. Skill and handed-down trade practices are the secret ingredients in traditional plaster, and they help make it a durable, original, and beautiful finish that old-house owners go to great lengths to keep. Need to tackle some plaster repair? Flat plastering is a time-honored, magical craft, the process of mixing dry powders and water into wet, plastic mortar, then spreading it over entire walls so that it creates a surface that is die-straight and alabaster smooth. If you are doing small patch-work, use a smaller bucket and mix by hand so that the plaster will set slower and give you time to work.Wall-lining textiles apply with adhesive like wallpaper and are ideal for covering multiple cracks and surface imperfections. Use the attachment for large jobs, where you will apply a lot of plaster in a short amount of time.
You must know that mixing the plaster with an attachment on your drill will cause the plaster to set much faster. An electric drill with a paddle attachment can save you a lot of time if you're mixing up large or multiple batches.Stir the mixture as you add in the plaster. If you add water to the plaster, you will have to apply pressure to mix the plaster at the bottom of the pail and you will over-mix the plaster and it will set too fast to work with. Always add the plaster mix to the water, not the other way around.Then, use a plunger or stirring rod to begin incorporating the dry plaster particles. Open a new bag of plaster mix and shake it into the bucket until it forms a mound above the surface of the water. Fill the bucket to the halfway mark with cool, clean water. Mix your plaster in a 5 or 7 gallon (18.9 or 26.5 L) (19-26L) bucket. Also a wall that is too dry causes the water to be absorbed out of the plaster and set before it has time to stick to the wall. Dust, soap, oil, tar and mold all cause the plaster not to adhere to the surface. You should always begin by cleaning your work surface, whether you’re resurfacing an old wall or plastering over brand new lath.
Spraying the wall with water will help the new plaster to adhere to the old wall. If it comes away caked with dust, it still needs some work. To test whether the wall is ready to accept new plaster, run your finger over the surface.Otherwise, there may be bumps and indentations on the finished wall. Make sure the wall and ceilings are plumb and flush before you start plastering.Repair any cracks in the wall before plastering it.Prime over stained areas to ensure the plaster will adhere properly.When you’re done, wipe the wall with a damp cloth to pick up what you loosened with the brush. Pay particular attention to the areas with heavy buildup, or where stripped layers of old plaster have left behind clumps. Scrub the wall from top to bottom with a dry stiff-bristled brush. Clean the wall to remove dust and debris.