How to Parge Concrete Walls
- 1). Remove mortar drips or clumps. Scrape this dried mortar away using a hammer and chisel. Some loose sections can also be scraped away with a putty knife.
- 2). Sweep away dust, sand and debris using a stiff wire brush.
- 3). Wash the walls using a garden hose and a mild detergent (like dish soap). Parging mix can adhere better to walls that are free of dirt and other contaminants.
- 4). Purchase a parging mix from your local hardware store. While most parging mixes contain only Portland cement, sand and lime, it can be difficult for novice installers to mix these ingredients in the correct proportions to ensure a successful installation. Parging mixes take the guesswork out of mixing, and can greatly reduce the risk of problems with your finished walls.
- 5). Blend your parging mix with water according to the instructions on the package. When properly blended, the mixture should form a thick paste, and should not be overly wet or runny.
- 6). Apply the mixture to the walls using a trowel. This first layer should not be thicker than 3/8". You can use your trowel to smooth out the parging or create a textured appearance as desired.
- 7). Scratch the surface with a plasterer's rake or broom to create a rough texture. Allow the wall to dry for 24 hours before applying a second coat of no more than 3/8". Skip this step if you are happy with the appearance of the wall after only one coat.
- 8). Mist the wall with water periodically over the next 5 days. This will help the parging to dry more slowly, which can reduce the risk of cracking or flaking over time.
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