Venetian plaster is a modern term that describes an ancient method of applying a stuccoed surface coating for walls. Venetian plaster (sometimes known as lime plaster) is essentially a putty made from fired limestone or marble dust mixed with water. As the surface is burnished after application, it develops a finish that has the look of genuine marble.
Traditionally, a Venetian plaster surface achieved its effect through the use of unique materials applied by a skilled craftsman. Fortunately, newer products have made it possible for do-it-yourselfers to create similar results in just a few steps and with no special training. Even better, today's products contain acrylic polymers that produce a more durable and long-lasting surface. With Venetian plaster, you get what you pay for in terms of quality. Bargain products are little more than thick paint, but the best Venetian plaster contains genuine marble dust mixed into an acrylic base.
You can find Venetian plaster in home centers and paint stores. It is sold in one-gallon cans, just like paint. Some products are sold already tinted, while others require that you or your dealer add universal colorants to achieve the color you want. The latter approach offers far more color choices.
One of the nice things about applying Venetian plaster is that you really do not need to buy many tools and materials to handle the job. The most basic Venetian plaster finish requires only a steel trowel and the plaster material. New drywall requires a preliminary coat of primer or flat wall paint, so you may also need an array of basic painting supplies.
Equipment / Tools
- Steel trowel or 4- to 6-inch drywall knife
- Work gloves
- Eye protection
- Paint tray
- 400 to 600 grit sandpaper
- Venetian plaster
- Drop cloth
- Painting primer
- Roller cover
- Universal colorants
- Topcoat or paste wax
Practice Your Skills
Venetian plaster is different from paint, and knowing how to paint a room does not automatically make you competent with Venetian plaster. A little time spent practicing with this new material will help you gain confidence and skill.
A good way to practice is to buy a couple of sheets of drywall, and then apply some plaster with a trowel, trying out different strokes and different angles. Experiment creating different amounts of texture on the surface.
If you are adding your own tint to the plaster, mix small batches with different quantities of colorants, taking notes as you do, until you find just the right mix.
Prepare the Room
Clear the room as much as possible, and spread a drop cloth on the floor. You can apply Venetian plaster to most walls and ceilings, but the surface should be flat and smooth. If there are any cracks or holes, fill and sand them first. Wash off any dirt and grease. The surfaces should be first primed or covered with flat paint before you apply Venetian plaster.
- Glossy paint surfaces can be plastered over, provided that you first sand the surface lightly to remove the sheen. Read the instruction on the can of Venetian plaster carefully for any additional preparation requirements.
- Steel trowels and drywall knives can have sharp corners that can leave lines and scratch marks in the plaster. To avoid this problem, round over the corners of the tools with 100-grit sandpaper.
- You may want to wear gloves when mixing and applying the plaster, as it can irritate the skin.
- Wear eye protection if you are spreading the Venetian plaster overhead.
- Mix the Venetian plaster thoroughly before each use.
Apply the First Coat
Open the can of Venetian plaster and, if necessary, add the tint. Mix the ingredients thoroughly.
Starting at a corner of the room, apply the plaster to the surface using a flexible steel trowel or a 4- to 6-inch-wide drywall knife. Apply a thin coat of plaster while holding the trowel at a 15- to 30-degree angle to the wall. Spread the plaster with strokes that vary in length and angle.
Don't worry about covering every square inch evenly. Let some of the original wall surface show through in spots, but keep the surface reasonably smooth. Clean off the trowel from time to time to keep dried plaster from getting into your finish.
Let the plaster dry thoroughly (about four hours) before applying the next coat.
Apply the Second Coat
Use the same color of Venetian plaster for the second coat. Holding the trowel or drywall knife at a 60- to 90-degree angle, apply another thin layer of plaster. Use overlapping (X-shaped) long and short strokes. Cover the surface thoroughly, filling voids and removing high spots.
Let the plaster dry for at least 24 hours before moving on to the finish treatment.
Burnish the Finish
The final steps of a Venetian plaster job involves burnishing the surface, and perhaps applying a topcoat.
To burnish, rub the surface with very fine sandpaper (400- or 600-grit) using a circular motion. Clean the surface with a damp cloth. You can create a more polished look by rubbing the surface with the flat side of a clean trowel or putty knife.
Apply a Top Coat (Optional)
As an optional final step, you can apply a topcoat to add durability to the surface. This is particularly recommended for rooms with high moisture (such as bathrooms) and areas with high traffic. If you decide to use a topcoat, be sure to choose a product that is specifically recommended for whatever brand of plaster you used. The topcoat is usually applied with a trowel soon after the plaster has dried. Keep in mind that the topcoat may darken the color a bit.
Once dry, you can burnish the surface again with the flat side of a clean trowel or putty knife.
You can also create a good sheen and add protection to the surface by using paste wax for the topcoat. Apply a thin coat of wax with a trowel, and then burnish the surface by rubbing it with the side of the trowel.