How to Smooth out Bumpy Walls for Painting

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How to Smooth out Bumpy Walls for Painting

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Why Bumpy Walls Happen

Before we dive into the fix, it helps to understand what causes uneven walls. Common culprits include poorly applied drywall compound, leftover texture (like popcorn or orange peel finishes), water damage, or years of repainting without proper prep.

Identifying what kind of bumps you’re dealing with will help you choose the best smoothing method.

Tools and Materials You’ll Need

To get started, you’ll want to gather some basic tools and supplies. Here’s what you’ll likely need:

• Drop cloths or plastic sheeting (to protect your floors)
• Safety gear: dust mask, safety glasses, gloves
• Sanding pole or hand sander
• Various grit sandpaper (start with 80–100 grit, finish with 180–220 grit)
• Joint compound or wall patch
• Putty knife or drywall knife
• Primer (preferably high-build or drywall primer)
• Optional: electric drywall sander or skim coat roller for large areas

If you’re working in a dusty area or with older paint that might contain lead, be sure to wear a high-quality respirator. (You can check out my post on the [Best Painting Masks] for safe and effective options.)

Step 1: Prep the Room

Start by clearing the space as much as possible. Cover furniture and floors with drop cloths or plastic sheeting. Remove outlet covers, light switch plates, and any nails or screws from the wall. If the walls are dirty, wipe them down with a damp sponge or cloth and let them dry completely.

Step 2: Identify and Mark Problem Areas

Examine the wall from different angles under good lighting. Look for raised textures, dents, old tape seams, or ridges. Lightly mark those spots with a pencil so you can target them when sanding or applying joint compound.

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Step 3: Sand Down High Spots

Using a hand sander or sanding pole, begin sanding the bumps down with coarse-grit sandpaper (80–100 grit). For heavy texture or old paint drips, you may need to use a drywall scraper first. Be patient—this step can be messy and time-consuming, but it’s crucial for a smooth result.

If you’re dealing with a large area or multiple rooms, investing in an electric drywall sander can save time and reduce fatigue.

Step 4: Apply Joint Compound to Low Areas

Once the high spots are knocked down, it’s time to fill the low areas. Use joint compound (also called drywall mud) and a wide drywall knife to skim over dips and uneven sections. Apply thin, even coats, feathering the edges to blend with the surrounding wall.

Let the first coat dry completely—usually 12–24 hours depending on humidity—then sand it lightly with a finer grit (120–150). Repeat the process with a second coat if needed for a completely even surface.

Step 5: Skim Coat Entire Wall (Optional)

For walls with extensive texture or damage, you might want to skim coat the entire surface. This involves applying a thin layer of joint compound over the whole wall, then smoothing it with a wide drywall knife or skim coat roller. It’s a bit more advanced but gives you that ultra-smooth, like-new finish.

Let the skim coat dry thoroughly, then sand it with 180–220 grit sandpaper until it’s smooth to the touch.

Step 6: Clean the Dust

Before priming, use a shop vacuum or dry cloth to remove dust from the walls and surrounding surfaces. Fine drywall dust can interfere with primer adhesion, so be thorough here.

Step 7: Prime the Surface

Now that your walls are smooth, seal them with a good quality primer. A high-build or drywall-specific primer is ideal, especially if you used a lot of joint compound. This step helps even out surface porosity and creates the perfect base for paint.

Once the primer is dry, run your hand across the wall. If it feels smooth, you’re ready to paint. If you feel any rough patches, a light sanding followed by spot priming can fix that quickly.

Bonus Tip: Choose the Right Paint Sprayer

Now that your walls are prepped, you might be wondering how to apply paint for the best finish. A high-quality paint sprayer can give you that flawless look, especially on a freshly smoothed surface. If you’re thinking about going that route, don’t miss my post on the [Best Paint Sprayers] for trusted recommendations and setup tips.

Conclusion

Smoothing out bumpy walls might seem like a big job, but taking the time to do it right will dramatically improve the final appearance of your paint job.

From proper prep to sanding and skim coating, each step builds on the next to give you walls that look brand new. Combine that with the right primer and painting tools, and your freshly painted room will be the envy of everyone who sees it.

Have questions about sanding, skim coating, or prepping textured walls? Drop them in the comments or get in touch—I’m always happy to help fellow DIYers get great results.