Plastering is a classic method of beautifying interior walls, providing a smooth and even finish. Many homeowners and professionals opt for plastering to create a polished look in their spaces. However, when it comes to certain types of surfaces, there may be questions as to whether plaster can be applied directly or if additional preparation is necessary. One such query often arises with backer board, a popular material used in construction and remodeling projects. In this article, we will explore the possibility of plastering on backer board and discuss the steps required for successful plaster application.
Understanding Backer Board:
Backer board, also known as cement board or cementitious backer unit (CBU), is a type of rigid panel made from a combination of cement and reinforcing fibers. It is commonly used as a substrate for ceramic or porcelain tiles in areas prone to moisture, such as bathrooms, kitchens, or laundry rooms. Backer board is highly durable, mold-resistant, and provides a stable surface for tile installation.
The short answer is yes, it is possible to plaster on backer board. However, certain considerations and preparatory steps must be taken to ensure a successful outcome. Plastering on backer board requires a slightly different approach compared to plastering on traditional sheetrock or plasterboard.
Preparing the Backer Board:
- Clean the Surface: Before plastering, ensure that the backer board surface is clean and free from debris, dust, and oil. Use a brush or vacuum cleaner to remove any loose particles that may hinder proper adhesion.
- Apply a Primer: Backer board is highly absorbent, so applying a primer or sealer is crucial to create a suitable surface for the plaster. Choose a primer specifically designed for cement-based materials, following the manufacturer’s instructions for application and drying times.
- Seal Joints and Corners: Backer board features joints and corners that should be sealed to prevent cracking or movement. Apply a joint compound recommended for use with backer board, embedding fiberglass mesh tape over joints and corners. Smooth out any excess compound and allow it to dry thoroughly as per product instructions.
The Plastering Process:
- Mixing the Plaster: Prepare the plaster mixture according to the manufacturer’s instructions. Ensure that the consistency is smooth and free from lumps. Use a mechanical mixer or mix by hand with a trowel to achieve the desired texture.
- Apply a Base Coat: Start by evenly spreading a base coat of plaster onto the primed backer board surface. Use the flat side of a trowel to create an even layer, roughly 1/8 to 1/4 inch thick. Maintain consistent pressure and avoid leaving lines or marks.
- Embedding Mesh: While the base coat is still wet, press a strip of fiberglass mesh into the plaster. This mesh acts as reinforcement, preventing cracks and improving the overall strength of the plaster layer.
- Apply Additional Coats: Once the base coat has dried and set, apply subsequent coats of plaster until the desired thickness is achieved. Use a trowel to smooth out each layer, ensuring even coverage and minimal imperfections. Allow each coat to dry before applying the next, following the manufacturer’s recommended drying times.
- Finishing Touches: Once the plaster has dried, use fine-grit sandpaper to smooth any rough spots or imperfections. The surface can then be primed and painted according to personal preference.
Benefits and Drawbacks:
Plastering on backer board offers several advantages. The use of backer board provides a stable and durable substrate, reducing the risk of cracks or unevenness in the plaster. Additionally, backer board is moisture-resistant, making it suitable for areas prone to high humidity.
However, it is essential to note that plastering on backer board may not replicate the exact appearance achieved on plasterboard. The texture and finish might differ slightly due to the inherent characteristics of backer board. Therefore, it is crucial to understand and accept these limitations before proceeding with plastering on this particular substrate.
While it is possible to plaster on backer board, proper preparation and execution are vital for a successful outcome. By following the necessary steps, such as cleaning, priming, and adequately applying plaster, homeowners and professionals can achieve a smooth and aesthetically pleasing finish. However, it is important to acknowledge the subtle differences in texture and appearance that may occur when using backer board instead of traditional plasterboard. With proper care and attention, plastering on backer board can provide long-lasting beauty to various interior spaces.