Have fun - How to repair damaged plaster walls

If you have all the necessary tools, your only expense is the cost of perlited plaster and ready-mix joint compound, both of which are affordable and in most hardware stores. Consisting of finely crushed gypsum rock and volcanic glass, perlited plaster is both lightweight and durable

Before Plastering: Excess moisture in the wall or room can affect the plastering, so make sure to fix any leaks or causes of moisture several weeks before plastering. The best temperature for plastering is between 55 degrees and 70 degrees. Keep the room at this temperature a least 24 hours before plastering to ensure that the walls are completely dry. The room must stay at this temperature during plastering and until the plaster has completely set. These repair tips apply only for plaster walls with lath backing and will not work for plaster board walls.

Similar steps are taken in repairing holes and cracks. Even the supporting wood frame area behind the plastered area, called the lath, can be easily repaired. Fixing holes without a lath is another easy job that just takes the right tools and a little skill.

Mixing: Follow manufacturer's instructions when mixing the plaster with water. Larger holes will need a thicker plaster mixture than smaller holes.

Safety First: When plastering, wear safety goggles, a long sleeve shirt and cotton work gloves for eye and skin protection. Wear a sanding respirator to prevent inhalation while breaking dried plaster or when mixing.

Repairing Holes

Tools and Materials You Need:

  • Cold chisel
  • Ball peen hammer
  • Utility knife
  • Paintbrush
  • Latex bonding agent (or spray bottle and water)
  • Regular formulation perlited plaster (sized for your repair job)
  • 10-inch wallboard knife
  • Spray bottle and water
  • Ready-mix joint compound
  • Sponge
  • Sandpaper
  • Interior primer

Chip Away Damaged Plaster: Remove the damaged plaster by using a cold chisel and a ball peen hammer to chip the damaged plaster off the wall. Be sure not to chip too hard or you will damage the lath, which is the wood structure that supports the plaster. Using a utility knife, smooth the inside edges of the hole.

Apply Latex Bonding Agent: To make sure the dry plaster and lath do not absorb too much moisture, use a brush to apply a latex bonding agent to the lath and exposed plaster. Ask your hardware store for the right bonding agent for plaster. If you do not have latex bonding agent, simply dampen the area well by spraying water with a spray bottle.

Apply and Scratch Plaster: Apply a layer of 3/8-inch thick plaster using a 10-inch wallboard knife. To help the second coat stick well, cross scratch the first coat of plaster as it begins to set.

Apply Second Layer: After letting the first coat dry for 24 hours, use a spray bottle to dampen the area with water. Distribute a second 3/8-inch thick layer of plaster over the hole and cross scratch as before. This layer must also dry for 24 hours.

Distribute Joint Compound: Apply the joint compound with a 10-inch wallboard knife after the second layer is dry. This final layer must be applied very thin to blend with the wall and must dry for 24 hours. Once completely dry, wipe the area with a damp sponge and sand until it is smooth.

Prime the Area: Paint the area with interior primer. After completely dry, the area can be finished with paint or wall covering.

Repairing Cracks

Tools and Materials You Need:

  • Utility knife
  • Spray bottle and water
  • -Bag of regular formulation perlited plaster (sized for your repair job)
  • 4-inch wallboard knife
  • Fine closed-coat sandpaper (150 grit)
  • Sponge
  • Interior primer

Smooth and Apply Plaster: Smooth cracked area with a utility knife, cutting away any jagged edges and dampen the area with a spray bottle and water. Apply a layer of plaster to the crack with a 4-inch wallboard knife, making sure it is even with the wall. Crack repairs usually need only 1 layer of plaster. Allow the area to dry for 24 hours .

Sand and Prime: Using a piece of fine closed-coat sandpaper (150 grit), sand the plastered area until it is smooth. Wipe the patch with a damp sponge and paint the area with interior primer, letting it dry completely. Finish the area by painting or covering with wallpaper.

Repairing Damaged Lath

Tools and Materials You Need:

  • Wood chisel (or mallet)
  • Metal lath (similar to heavy screen)
  • 6-inch piece of wire
  • Wooden dowel
  • Bag of regular formulation perlited plaster (sized for your repair job)
  • Wire cutters
  • Ready-mix joint compound
  • Closed-coat sandpaper (150 fine grit)

Insert Metal Lath in the Hole: If the lath behind the hole is damaged, cut the damaged wood out with a wood chisel or a mallet. Take a piece of metal lath, which is similar to heavy screen, and insert a wire loop at the center of the lath. Holding the wire tightly, push the metal lath into the hole and pull the wire so that the metal lath is pressed firmly against the inside of the hole.

Apply Plaster Over Lath: Twist the metal wire tightly around a wooden dowel making sure the dowel is pressed firmly against the wall. Apply a coat of plaster and cross scratch it as it begins to set.

Distribute Joint Compound: Once the area is dry, remove the wooden dowel and cut the wire with wire cutters. Apply your thin layer of joint compound and let it dry for 24 hours. The area can be painted or wallpapered after sanding and wiping down with a damp sponge.

Repairing a Hole without Lath

Tools and Materials You Need:

  • Wallboard saw
  • Gypsum lath (or 3/8-inch thick wallboard)
  • Power screw driver
  • Wallboard screws
  • Regular formulation perlited plaster
  • Trowel
  • Ready-mix joint compound
  • Spray bottle and water
  • 10-inch wallboard knife
  • Small-cell polyurethane sponge
  • Fine-closed sandpaper
  • Paintbrush
  • Interior primer

Install Wallboard Over the Hole: If there is a hole in your plaster without any lath behind the hole, you need to install a piece of wallboard or gypsum lath over the area without lath before plastering. Cut the wallboard or gypsum lath to fit the area without the lath. Fasten the corners of the gypsum lath or wallboard to the existing lath behind the plaster. Use a power screw driver and wallboard screws.

Apply Plaster: Using a trowel, apply plaster over the hole covering the patch and filling the entire hole. Let the area dry for 24 hours.

Apply Joint Compound: < Use a 10-inch wallboard knife to apply a thin layer of joint compound about 5 inches beyond the edge of the hole and let it dry for 24 hours. Wipe the area with a damp sponge and sand. Using a paintbrush, coat the area with a layer of interior primer and let it dry completely before painting or wallpapering.

Article from: http://doityourself.com