Here's how you can effectively plaster over a painted wall:
Preparation is Key
Before applying any plaster, thorough preparation is crucial for successful adhesion and a smooth finish.
Step 1: Remove Loose Paint
- Scrape: Use a scraper to remove any loose or flaking paint. This will create a stable surface for the plaster to adhere to.
Step 2: Sand the Surface
- Sand: Sand the wall down until the surface is smooth. This will improve adhesion by creating a slightly textured surface for the bonding agent to grip.
Step 3: Apply Bonding Agent
- Thistle Bond or PVA: Apply one coat of Thistle Bond or two coats of PVA to the wall. This is a crucial step to ensure the plaster sticks to the painted surface.
- Bonding Agent Type: Thistle Bond is a specialized bonding agent for plastering, while PVA is a more common alternative. Choose based on your availability and the severity of the painted surface.
- Application Technique: Apply the bonding agent evenly, ensuring complete coverage of the area you intend to plaster.
Step 4: Plastering
- Tacky Stage: Apply plaster while the bonding agent is still tacky. This is important for the plaster to properly bond with the surface.
Step-by-Step Guide
| Step | Action | Description |
|---|---|---|
| 1 | Scrape Loose Paint | Remove any peeling or loose paint with a scraper. |
| 2 | Sand the Wall | Sand the painted surface until it is smooth and provides a good key. |
| 3 | Apply Bonding Agent | Apply Thistle Bond or two coats of PVA to the prepared wall surface. |
| 4 | Plaster while Tacky | Apply the plaster while the bonding agent is still tacky to ensure adhesion. |
Tips for Success
- Clean the Wall: Before starting, ensure the wall is clean and free from dust or grease.
- Timing: Applying the plaster while the bonding agent is tacky is crucial for proper adhesion.
- Plaster Type: Choose a suitable plaster for your specific application.
- Professional Help: If you are unsure, consider consulting a professional plasterer for advice or to complete the job.
By following these steps, you can successfully plaster over a painted wall, achieving a smooth and durable surface.
