A chipped plaster wall can be anxiety-evoking for homeowners, but it doesn't need to be that way. Plaster chips can be easily repaired by using the right materials and techniques. Keep reading for more information on plaster repair:
Tools and materials needed
Powdered Plaster of Paris
Metal-bladed putty knife
Electric drill with ¼-inch masonry drill bit
Drill mixing attachment
Tube of construction adhesive
1. Inspect the lath for soundness - before repairing the wall, you will need to inspect the lath in the vicinity of the chip. Lath are the underlying thin strips of wood that form the base of support for the plaster. It's important to make sure they are structurally-sound with no signs of rotting or loosening. If you discover problems with any segments of the lath, they will need to be cut-out and replaced with new strips of wood before proceeding.
2. Attach the surrounding plaster to the lath - whenever a chip or other breach of integrity occurs in a plaster wall, the surrounding plaster is prone to separate from the lath. This must be corrected before attempting to repair a chip; otherwise, the plaster wall will possibly break and fall away from the lath, thus resulting in an even bigger area of damage.
To correct this problem, the existing plaster will need to be glued to the lath. Begin by drilling ¼- inch holes around the edge of the damaged area; drill each hole approximately 2 inches apart from each other and 1 inch from the edge of the chip. Be sure to use a masonry bit for best results with the hard plaster.
Once the holes are drilled, remove plaster dust and debris with a wet/dry vacuum; place the suction attachment directly over the holes to suck-up as much loose material as possible. Next, cut the tip of the construction adhesive tube to a diameter just less than ¼-inch, and insert the tip into the holes you just drilled. Gently squirt construction adhesive into each hole until you see it appear from under the edge of the plaster and push out onto the lath. Provide adequate time for the adhesive to dry before moving on to the next step.
3. Mix the plaster - after the surrounding plaster is firmly secured to the lath, you are ready to mix the new batch of plaster. To mix, add about one quart of clean tap water to a five-gallon bucket and pour in about 2 cups of Plaster of Paris. Use a drill mixing attachment to make mixing simpler and faster.
If the mixture appears to be too dry, add about ½-cup of water at a time and stir; if the mixture is too wet, add one cup of Plaster of Paris at a time and continue to stir. The desired consistency is similar to peanut butter and will not fall off an overturned trowel when mixed correctly.
4. Apply the plaster - with the trowel, begin taking small scoops of plaster and pushing them into the chipped area; be sure to work plaster into the surrounding areas and into nearby gaps or spaces. In addition, don't forget to cover the holes you drilled in step 2 with plaster. Smooth out the plaster using a putty knife or trowel blade, but don't worry if you still have a few minor rough spots. Allow the plaster to dry completely before proceeding.
5. Knock-off rough spots - once the plaster has dried, use a putty knife to scrape off the roughest spots. Keep the blade at a low angle relative to the wall and be careful not to gouge into the plaster as you scrape.
6. Apply joint compound - use a putty knife to apply a thin layer of joint compound to the top of the scraped plaster. The layer should be thin enough so you can still see the dried plaster beneath the compound. Smooth it out as much as possible with the putty knife, then use a slightly damp sponge to smooth the compound further and blend the edges. Allow the compound to dry completely, then paint over the area to complete the repair.