Plastering Concrete Walls

At some point or another a homeowner may be faced with the task of plastering concrete walls--to change the appearance of the wall, make it resistant to moisture , eliminate unsightly cracking or to add texture. Plastering kitchen, bathroom  or concrete living room walls is easy and the finished wall will be able to withstand abrasion.

Follow these instructions to learn how to plaster concrete walls in your home.  

Step 1: Prepare Your Concrete Walls

Before you begin to plaster your concrete walls you need to remove peeling paint and flaking bits of old plaster. Your walls should be free of paint, oil and dust so the plaster can bond properly.

Caulk cracks and kill any mold on the walls. Use a wire brush to clean stains left by the mold or mortar joints.  

Step 2: Apply a Layer of Dash

The texture of the concrete walls should be sufficiently rough so the plaster will adhere to it. To help achieve this, you need to make dash by mixing 1 part cement to 1½ parts coarse sand and add enough water so the mixture has a runny consistency. Apply a coat of the mixture to your concrete wall before plastering it and allow it to dry for a day. For a flat finish apply a layer of dash that is almost liquid in consistency.  

Step 3: Mix the Plaster

Mix your plaster according to the manufacturer's instructions, preferably in an area away from drying winds and direct sun. You will probably need to add some plaster sand to your all purpose plaster and mix it with water--making sure you use the batch within about 2 hours. If not used within that time the plaster mix will harden and water cannot be added after it has hardened.  

Step 4: Apply the Plaster

Apply a base coat of plaster over the layer of dash with a steel trowel. The layer should be somewhere from 10 to 15 mm thick. Apply it in small strokes, making sure it is level and uniform. If you want a flat wall, smooth the plaster out. Leave it rough if you prefer a textured look.

If you want to apply a single coat of plaster, make sure it is no thicker than 10 to 15 mm. Remember the thickness of the top coat should be 5 to 10mm.  

Step 5: Care of Your Plastered Walls

After you have successfully applied plaster, it is imperative you protect your walls from the sun and wind. You can do this by covering them with a plastic sheet the size of the walls or by using several pieces of sheets joined together for larger walls. Keep your walls moist for a minimum of 7 days for the plaster to set properly. 

After your plastered concrete walls have dried, you can paint them, apply wallpaper or simply drill holes into them to hang pictures.