How to Clean Walls Before Painting

Painting walls can seem like a simple task, but proper wall preparation is crucial for achieving an attractive and long-lasting paint job. Cleaning walls thoroughly prior to painting removes dirt, grease, and other contaminants that can cause paint failure down the road. Follow these steps for cleaning walls properly before you break out the paint.

Gather Your Cleaning Supplies

To clean walls effectively before painting, you’ll need:

  • Bucket
  • Mild detergent or degreasing cleaner
  • Clean rags
  • Sponges
  • Nylon scrub brush
  • Scraper (for removing loose paint)
  • Sandpaper
  • Drop cloths
  • Ladder

Avoid using abrasive cleansers or anything acidic when cleaning, as these can damage drywall and plaster. A mild detergent, all-purpose cleaner, or degreaser will get walls clean without being too harsh.

Wash the Walls

Fill your bucket with warm water and add a small amount of mild detergent, degreaser, or all-purpose cleaner. Dip your sponge or rag into the solution, wring out excess water, and wipe down the walls starting at the top and working your way down.

Change out the water frequently so you’re always using a clean solution. Pay close attention to cleaning greasy areas around light switches, near the top of walls where hands touch, and around door frames.

For grimy areas, allow the cleaning solution to soak for a few minutes before scrubbing. Use a nylon scrub brush for textured walls. Rinse the walls with a damp sponge after cleaning.

Let the walls fully dry before moving on to spot repairs and sanding. Running fans and opening windows can help speed drying time.

Repair Wall Damage

Inspect the walls closely and make any needed repairs before painting. Here are some common issues to look out for:

  • Holes or cracks: Fill small holes with spackle or drywall putty using a putty knife. For cracks, remove any loose paint first then apply joint compound over the crack with a putty knife. Allow repairs to dry fully then sand until smooth.
  • Loose paint: Use a scraper to remove any paint that is blistered, cracked or peeling away from the wall. Feather surrounding areas by sanding.
  • Nail/screw pops: Reset protruding nails by gently tapping them back into the wall using a hammer and nail set. Fill over the holes with spackle, allow to dry, then sand.

Make sure any sanded areas are cleaned to remove dust before painting. Wipe with a tack cloth after sanding for the smoothest results.

Sand Away Rough Spots

Lightly sanding walls prior to painting removes gloss, roughness, and any leftover dried drips or splatters from the previous paint job. Use fine grit sandpaper (120-220 grit) and sand in the direction of the wall texture.

Be sure to smooth any repairs you made so they’re flush with the rest of the wall. Wipe away all dust with a dry cloth once sanding is complete.

Clean Away Dust

Paint adheres best to a dust-free surface, so removing all traces of dust is key after cleaning and sanding.

Use a dry microfiber cloth or tack cloth to wipe away dust from the walls, baseboards, trim, and any other nearby surfaces. Vacuum the walls as an extra step to ensure no specks are left behind.

Change vacuum bags after use to prevent kicked-up dust from resettling.

Set Up Your Workspace

Before opening any paint cans, use drop cloths to cover floors and furniture. Tape down the edges of drop cloths to keep them in place.

Clear furniture or other items away from the immediate work area. Use painter’s tape and drop cloths to mask off any areas you don’t want painted, like baseboards, window frames, or light fixtures.

Ventilate the Room

Once your workspace is prepped, open windows and doors to allow for plenty of fresh air circulation while painting. Running fans helps dissipate fumes as well.

If possible, shut down central heating and air to avoid spreading paint vapors throughout the home.

Now You’re Ready to Paint!

With clean, dust-free walls and proper ventilation in place, you can move on to priming and painting confidently, knowing that thorough surface preparation will help your fresh coat of paint adhere smoothly and last beautifully. Don’t forget to use high-quality applicator tools like high-density rollers and quality nylon or polyester brushes.

Taking the time to properly clean and prepare your walls prior to painting makes all the difference for a professional looking, durable finish. Just follow these key steps—washing, repairing damage, sanding, removing dust, and ventilating the area—and you’ll avoid peeling, wrinkling, or yellowing paint down the road.

FAQs About Cleaning Walls Before Painting

Here are answers to some frequently asked questions about getting walls properly prepped for painting:

How do I clean greasy walls before painting?

Mix an alkaline-based degreaser or tsp substitute with water according to package directions. Apply to greasy areas and let soak 5-10 minutes before scrubbing with a stiff nylon brush and rinsing clean. Repeat as needed until grease is fully removed.

What is the best way to clean walls before painting?

Wash walls with a mild detergent and warm water using a sponge or rag. Rinse thoroughly then allow to fully dry before painting. Spot clean any extra dirty areas using the washing method.

Should walls be cleaned before painting?

Yes, it is important to properly clean walls before painting to remove any dirt, grease, soap scum, or other grime that could interfere with paint adhesion. Always clean walls prior to painting for best results.

How do you prepare flaking paint for painting?

Use a paint scraper to remove any loose, cracking or peeling paint. Sand rough edges smooth. Wipe away dust, then spot prime any bare areas with an appropriate primer before applying new paint.

Do walls need to be primed before painting?

If walls were properly prepped and are in good condition with intact paint, priming may not be absolutely necessary. But primer still provides extra adhesion and uniformity, making it a good idea for most paint jobs.

How long do you have to wait to paint after cleaning walls?

Allow cleaned walls to dry fully before painting. This could take 4-8 hours or longer depending on climate conditions. Accelerate drying by opening windows and using circulating fans. Walls should not feel cool or damp before painting.

Do walls need to be washed before painting?

Yes, washing walls before painting helps remove surface grease, dirt and other contaminants that could impede paint bonding. Use a diluted mild detergent and rinse walls thoroughly after washing. Allow walls to fully dry before painting.

Do you have to sand walls before painting?

Lightly sanding provides the best surface for paint to adhere to. Sanding also eliminates gloss, roughness and flaws. Use fine 120-220 grit sandpaper and be sure to wipe away dust before painting.

Is TSP necessary for cleaning walls before painting?

While TSP (trisodium phosphate) is an effective heavy-duty degreaser and cleaner, it is quite caustic and requires careful safety precautions. A milder detergent or all-purpose cleaner can usually get walls clean enough for painting without the risks of TSP.


Preparing your walls properly before painting is a key step that makes all the difference in achieving a smooth, professional looking finish. By thoroughly washing, repairing, sanding, and dusting the surface beforehand, you ensure that paint adheres tightly and evenly with no peeling or chipping down the road. Don’t skip corners when prepping – take the time to clean meticulously, smooth flaws, eliminate gloss, remove all dust and set up tarps. Following these best practices for cleaning walls before painting will lead to greater ease of application and a durable, lasting paint job.