You can wallpaper over painted walls, but proper preparation is key for a successful and long-lasting result. Here's a detailed guide:
1. Assess the Existing Paint
- Type of Paint: Emulsion paint is generally suitable for wallpapering over. Gloss or semi-gloss paint needs more rigorous preparation.
- Condition: Check for peeling, cracking, or flaking paint. These issues must be addressed before wallpapering.
2. Prepare the Walls
This is the most crucial step!
- Clean the Walls: Wash the walls with a mild detergent and water to remove any dirt, grease, or stains. Rinse thoroughly with clean water and allow to dry completely.
- Sand the Walls: Sanding is essential, especially if the paint is glossy or semi-gloss. Use a medium-grit sandpaper to create a slightly rough surface that the wallpaper adhesive can grip. Remove all sanding dust with a damp cloth.
- Repair Imperfections: Fill any holes, cracks, or dents with spackle or joint compound. Let it dry completely and then sand it smooth. Again, remove all sanding dust.
3. Priming (Recommended)
While not always necessary, priming offers significant benefits:
- Enhances Adhesion: Primer creates a more uniform and porous surface for the wallpaper adhesive to bond to.
- Seals the Surface: Primer prevents the paint from absorbing the wallpaper adhesive too quickly, giving you more time to position the wallpaper.
- Provides a Uniform Color: This prevents any color variations from the underlying paint from showing through the wallpaper, especially with thinner wallpapers. Use a primer specifically designed for wallpaper, or a PVA solution. Let the primer dry completely according to the manufacturer's instructions.
4. Size or Seal the Wall (Alternative to Primer)
If you're not using a primer, sizing the wall is beneficial.
- Wallpaper Size: Apply a coat of wallpaper size (a diluted wallpaper adhesive or a specially formulated sizing product) to the wall. This creates a slightly tacky surface that improves adhesion. Follow the manufacturer's instructions for application and drying time. Alternatively, a PVA solution can be used.
5. Wallpapering
- Follow Wallpaper Instructions: Each wallpaper has specific hanging instructions. Read and understand these before you begin.
- Apply Adhesive: Apply wallpaper paste evenly to the back of the wallpaper, following the manufacturer's instructions.
- Hang the Wallpaper: Carefully align the wallpaper with the wall and smooth it out using a smoothing tool or a clean, damp sponge. Work from the center outwards to remove any air bubbles.
- Trim Excess: Use a sharp utility knife to trim any excess wallpaper at the top and bottom.
- Clean Up: Wipe away any excess adhesive with a damp sponge.
Summary
Wallpapering over painted walls is achievable with proper preparation. Cleaning, sanding, repairing imperfections, and priming (or sizing) are crucial steps to ensure a smooth, long-lasting result. Always follow the wallpaper manufacturer's instructions.
