Painting over a rough or textured surface requires careful preparation to achieve a smooth, professional finish. Simply applying new paint won't hide existing texture or imperfections; it will often accentuate them. The key is to address the surface roughness before you paint.
If you're dealing with a heavily textured wall and want a smooth result, a common and effective method involves applying a technique called skim coating.
Preparing the Surface
Before tackling the roughness, you need to prepare the wall:
- Clean: Wash the wall thoroughly to remove dirt, grime, and grease. A simple solution of soap and water works well. Allow it to dry completely.
- Repair: Fix any cracks, holes, or peeling paint. Scrape away loose paint and fill imperfections with appropriate patching compound. Sand smooth once dry.
Addressing Rough Texture: The Skim Coat Method
If the "roughness" is due to an intentional texture or simply a very uneven surface, applying a skim coat is the recommended approach, especially if you desire a smooth finish.
As the reference states: "If you want to paint over a textured wall without keeping the texture, add a skim coat before painting to achieve a smoother finish. Skim coating is the process of spreading a thin layer of drywall joint compound over the walls to fill in valleys and bumps in the texture."
Here’s a breakdown of the process:
- Mix Joint Compound: Prepare drywall joint compound (also known as mud). You can use premixed or powder varieties. If using powder, mix it to a smooth, lump-free consistency, similar to peanut butter or thick pudding.
- Apply Thin Layers: Using a wide drywall knife or trowel (e.g., 10 or 12-inch), scoop a small amount of compound onto the blade. Start at the top of the wall and spread a very thin layer over the surface, holding the knife at a slight angle to the wall. The goal is to fill in the low spots and lightly cover the high points.
- Feather Edges: Work your way across the wall, overlapping your strokes slightly. Try to keep the layers as thin and smooth as possible.
- Allow to Dry: Let the first coat dry completely. This can take several hours depending on humidity and thickness. The compound will turn lighter in color when dry.
- Inspect and Repeat: Once dry, inspect the wall. You will likely still see some texture or unevenness. Apply a second (or even a third) thin coat if necessary to achieve the desired level of smoothness. Allow each coat to dry fully before applying the next.
Sanding and Priming
After the final skim coat is completely dry:
- Sand Smooth: Use fine-grit sandpaper (e.g., 150-grit or higher) or a pole sander to gently sand the entire surface. This removes any knife marks, ridges, or small bumps, creating a smooth finish. Wear a dust mask and protect the area from dust.
- Clean Dust: Wipe down the walls with a damp cloth or use a vacuum with a brush attachment to remove all sanding dust.
- Prime: Apply a high-quality primer designed for previously repaired or textured surfaces. Primer seals the joint compound, helps the paint adhere better, and ensures a uniform finish.
Painting
Once the primer is dry according to the manufacturer's instructions, you can proceed with painting the wall with your desired color and finish. Two coats of paint are usually recommended for best coverage and durability.
By taking the time to properly prepare the surface and address the roughness, particularly by using the skim coating technique for textured walls, you will achieve a much smoother and more professional-looking painted finish.
