How to Prepare Walls for Painting: Repair, Clean, and Prime Like a Pro

Introduction

Here's the truth professional painters know: wall preparation matters more than the paint itself. We've seen countless Bay Area homeowners apply expensive premium paint over poorly prepped walls—walls with grease residue, unfilled holes, dusty surfaces, or unprimed repairs. The result? The paint looks terrible, fails prematurely, or shows every flaw that proper prep would have hidden.

At Lamorinda Painting, we've been prepping and painting Bay Area walls since 2003. We're based in Lafayette and serve Lamorinda, the East Bay, and the greater Bay Area. We know that wall preparation is tedious, time-consuming, and unsexy work that nobody wants to do. It's also the single biggest factor determining whether your paint job looks professional or amateurish.

Proper preparation can take longer than the actual painting—especially in older Bay Area homes where walls have decades of patching, repairs, texturing mismatches, and multiple layers of paint. But skip or rush this work, and you'll see every shortcut in the finished result.

In this guide, you'll learn the complete professional wall preparation process—how to repair damage, clean surfaces properly, prime correctly, and create the smooth, clean substrate that makes paint look stunning. And if you'd prefer to hire professionals who do this work expertly every day, we're always happy to provide a free estimate.

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Why Wall Preparation Matters More Than You Think

Before we dive into the how-to, understand what poor preparation costs you.

What Happens When You Skip Preparation

According to Sherwin-Williams application guidelines, inadequate surface prep causes:

Paint adhesion failure: Paint peels or bubbles off dirty, greasy, or powdery surfaces.

Visible imperfections: Holes, cracks, and repairs show through paint, sometimes more obviously than before painting.

Uneven appearance: Glossy spots from old stains, dull spots from repairs, and color variation from inconsistent priming create a blotchy finish.

Premature wear: Paint on improperly prepped surfaces wears faster, requiring repainting sooner.

Wasted materials: Poor prep often requires additional coats of expensive paint trying to hide problems that proper prep would have solved.

What Proper Preparation Delivers

According to Benjamin Moore technical guidance, thorough surface prep ensures:

• Maximum paint adhesion and longevity
• Uniform appearance with consistent sheen and color
• Smooth finish that looks professional
• Fewer coats of finish paint required
• Results that last 5-7+ years instead of 2-3 years

In Bay Area homes, particularly older properties in Lafayette, Orinda, Oakland, and Berkeley with decades of patches and repairs, proper prep can be the difference between a beautiful result and an obvious amateur job.

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Step 1: Assessment and Planning

Before you touch anything, assess your walls thoroughly.

Wall Condition Assessment

Walk through each room and identify:

Surface type: Drywall, plaster, wood paneling, textured ceiling, previously painted, wallpapered, etc.

Damage to repair: Holes from removed fixtures, nail pops, cracks (especially in older plaster), water damage, loose or peeling paint.

Texture issues: Mismatched texture from previous repairs, knockdown or orange peel texture that needs addressing, textured ceilings you might remove.

Stains and discoloration: Water stains, smoke damage, grease (especially kitchens), marker or crayon (kids' rooms), bleeding wood knots.

Surface contamination: Grease, dust, cobwebs, mildew (bathrooms), nicotine residue (older homes).

Material Planning

Based on your assessment, gather materials. According to PPG's preparation guidance, you'll likely need:

Repair materials:

• Spackling paste for small holes
• Joint compound for larger repairs and skim coating
• Drywall tape (paper or mesh) for cracks
• Sandpaper (80-grit, 120-grit, 220-grit)
• Caulk for gaps around trim

Cleaning materials:

• TSP (trisodium phosphate) or TSP substitute
• Degreaser for kitchens
• Mildew cleaner for bathrooms
• Clean rags and sponges
• Vacuum with brush attachment

Priming materials:

• Primer appropriate to your situation (discussed below)
• Primer for stains if needed

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Step 2: Cleaning Walls Thoroughly

Clean walls before any repair or painting work. This seems obvious but is frequently skipped or done inadequately.

Why Cleaning Matters

According to Behr's surface preparation guides, paint doesn't adhere properly to:

• Greasy surfaces (cooking residue, hand oils)
• Dusty surfaces (common in Bay Area homes, especially inland areas)
• Mildew or mold (bathrooms, poorly ventilated rooms)
• Nicotine or smoke residue (older homes)

Even seemingly clean walls accumulate invisible oils from hands touching walls, cooking vapors, and general airborne contamination.

The Professional Cleaning Process

Step 1: Dust removal Use a vacuum with brush attachment to remove loose dust, cobwebs, and debris from walls and ceiling. Pay attention to corners, baseboards, and crown molding.

Step 2: Wash walls Mix TSP or TSP substitute according to package directions (typically 1/4 cup per gallon of water). Wear gloves—TSP is caustic. Wash walls from bottom to top using a sponge or cloth, working in 3-4 foot sections.

According to This Old House cleaning recommendations, washing from bottom up prevents streaking from dirty water running down clean wall.

Step 3: Rinse thoroughly Wipe walls with clean water to remove cleaning solution residue. TSP left on walls can interfere with paint adhesion.

Step 4: Dry completely Allow walls to dry 24 hours before proceeding. Don't paint over damp walls.

Special Cleaning Situations

Kitchen grease: Use dedicated degreaser (like Krud Kutter) before TSP washing. Grease is paint's enemy—it must be completely removed.

Bathroom mildew: Clean with mildew-killing solution (bleach solution or commercial mildew cleaner) before TSP. According to Dunn-Edwards bathroom prep guidance, painting over mildew causes paint failure.

Smoke/nicotine residue: Requires heavy-duty cleaning and stain-blocking primer. In severe cases, consider professional cleaning before painting.

Bay Area dust (particularly inland): Our dry climate creates significant dust accumulation. Extra-thorough vacuuming and washing is essential in Walnut Creek, Concord, Antioch, and similar areas.

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Step 3: Repairing Damage

Now that walls are clean, repair all damage before priming or painting.

Small Holes and Nail Pops

According to Sherwin-Williams repair guidance:

Holes under 1/4 inch:

• Clean loose material from hole
• Apply lightweight spackling paste with putty knife
• Smooth flush with wall surface
• Allow to dry completely (2-4 hours)
• Sand smooth with 220-grit sandpaper
• Wipe dust with damp cloth

Holes 1/4 to 1 inch:

• Apply spackling or joint compound in thin layers
• Build up in 2-3 applications rather than one thick application
• Each layer must dry before applying next
• Sand smooth with 220-grit
• Prime repaired area before painting

Nail pops (nails pushing through drywall):

• Drive protruding nail deeper into stud
• Add new drywall screw 2 inches above or below original nail
• Apply joint compound over both, feathering edges
• Sand smooth when dry

Larger Holes and Damaged Areas

Holes 1-6 inches: According to Benjamin Moore's drywall repair guidance:

• Cut damaged area into clean square or rectangle
• Cut drywall patch to fit opening
• Secure patch with drywall clips or wood backing
• Tape seams with drywall tape
• Apply joint compound in 3 coats, feathering each coat wider
• Sand smooth with 120-grit, then 220-grit
• Prime entire repaired area

Holes larger than 6 inches: Consider hiring a drywall professional. Large repairs require skill to blend seamlessly.

Cracks (Especially in Older Homes)

Bay Area's older homes—particularly plaster homes in Lafayette, Orinda, Berkeley, and Oakland—develop cracks from settling, seismic movement, and age.

Hairline cracks:

• Widen crack slightly with putty knife or can opener to create V-shaped groove
• Fill with spackling or flexible caulk
• Smooth flush with wall
• Sand lightly when dry

Wider cracks (1/8 inch+):

• Use mesh drywall tape over crack
• Apply joint compound over tape
• Feather edges 6-8 inches beyond crack
• Apply 2-3 coats, sanding between coats
• Prime before painting

Recurring cracks: If cracks reappear after repair, you may have structural movement. Consider fiberglass mesh tape and flexible caulk, or consult a structural engineer for serious cases.

Texture Matching

One of the hardest prep challenges: matching existing wall texture on repairs.

According to Family Handyman's texturing advice:

• Identify your texture type (smooth, orange peel, knockdown, skip trowel, etc.)
• Practice on scrap drywall before attempting wall
• For orange peel: use thinned joint compound in spray texture gun
• For knockdown: apply joint compound, allow partial drying, then knock down with trowel
• For smooth walls: skim coat repair with joint compound, feather edges thin, sand perfectly smooth

In Bay Area homes, many 1970s-1980s houses have orange peel or knockdown texture. Matching this requires practice. If you can't match it, consider hiring a professional for this step.

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Step 4: Sanding

Sanding creates the smooth surface that makes paint look flawless.

What to Sand

According to PPG surface preparation guidance, sand:

• All repaired areas until flush and smooth
• Glossy previously painted surfaces to create "tooth" for new paint
• Any bumps, drips, or imperfections from previous paint jobs
• Edges where old paint is peeling to feather the edge

Sanding Technique

Repair areas: Start with 120-grit to level, finish with 220-grit to smooth Previously painted glossy surfaces: 150-grit to scuff surface Final smoothing: 220-grit for perfect finish

Important: Wear a dust mask. Sanding creates fine dust that shouldn't be inhaled. In older Bay Area homes (pre-1978), be aware of potential lead paint—testing is wise before heavy sanding.

After sanding: Vacuum walls and wipe with slightly damp cloth to remove all dust. Dust left on walls creates bumps under new paint.

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Step 5: Priming

Primer is not optional. It's a separate product that solves specific problems paint can't solve alone.

When Primer Is Mandatory

According to Sherwin-Williams and Benjamin Moore priming guides, you must prime:

• All repaired areas (spackling, joint compound, new drywall)
• Bare wood or MDF
• Stained areas (water, smoke, grease, marker, tannin bleeding)
• Dark colors you're painting over with lighter colors
• Dramatic color changes (red to white, dark blue to beige, etc.)
• Glossy surfaces you've sanded
• Previously unpainted drywall

Types of Primer and When to Use Each

PVA Primer (Polyvinyl Acetate):

• For new, unpainted drywall only
• Seals porous drywall so finish paint doesn't soak in
• Not for repairs, stains, or color changes
• Example: Sherwin-Williams ProBlock, Benjamin Moore Super Hide

Stain-Blocking Primer:

• For water stains, smoke damage, grease, marker, crayon, tannin bleeding
• Oil-based (strongest) or shellac-based (also very strong)
• Seals stains so they don't bleed through finish paint
• Example: Kilz Original (oil), BIN (shellac), Kilz 2 (water-based)

High-Build Primer:

• For filling minor imperfections and creating uniformly smooth surface
• Thicker than standard primer
• Good for skim-coated areas and textured surfaces you're smoothing
• Example: Sherwin-Williams PrepRite ProBlock

Bonding Primer:

• For glossy surfaces, tile, glass, or slick surfaces paint doesn't normally stick to
• Creates mechanical bond through special adhesion chemistry
• Example: Sherwin-Williams Extreme Bond, Benjamin Moore Stix

Tinted Primer:

• Primer tinted toward finish color
• Reduces coats needed for dramatic color changes
• Example: Have primer tinted to 50% of finish color when going from white to dark color

Priming Technique

According to Behr's primer application guidance:

Spot priming (repairs and stains only):

• Prime repaired areas and stains first
• Feather primer edges beyond repair by 2-3 inches
• Allow to dry completely
• Lightly sand edges of spot-primed areas to blend

Whole-wall priming (new drywall, dramatic color change):

• Apply primer as you would paint
• Use roller for large areas, brush for edges and details
• One coat usually sufficient
• Allow to dry per manufacturer instructions (usually 1-4 hours)
• Lightly sand any drips or rough spots

Bay Area note: In coastal areas with higher humidity (Richmond, El Cerrito), allow extra drying time for primers. Inland areas (Walnut Creek, Concord) allow faster drying.

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Step 6: Final Inspection and Touch-Up

Before painting, inspect your prep work critically.

What to Look For

• Feel the walls: Run your hand over repairs. Feel any bumps or ridges? Sand them.
• Look at angles: View walls from different angles and in different light. Shadows reveal imperfections you might miss straight-on.
• Check primer coverage: Any stains bleeding through? Missed spots? Apply second coat of primer where needed.
• Inspect texture: Do repairs blend with surrounding wall? If not, apply texture or additional skim coat.

According to This Old House quality standards, professionals often spend 60-70% of project time on prep and only 30-40% on actual painting. That ratio should tell you something about what matters.

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Special Prep Situations in Bay Area Homes

Our regional housing stock creates specific prep challenges.

Older Plaster Walls (Pre-1950s Homes)

Common in Lafayette, Orinda, Oakland, Berkeley, and San Francisco.

Challenges: Cracks from age and settling, loose or crumbling plaster, texture differences

Prep approach:

• Test for soundness (tap wall—hollow sound indicates loose plaster)
• Repair loose areas with plaster repair products or consider skim coating over entire wall
• Use flexible caulk in cracks that may move
• Prime with high-quality primer to seal old plaster

Textured Walls and Ceilings (1970s-1980s Homes)

Common throughout East Bay in homes from this era.

Challenges: Matching texture, repairing without obvious patches

Prep approach:

• Match texture type exactly (practice first)
• Consider removing texture entirely and skim coating smooth for modern look
• If texture is extreme, hire professional—this is skilled work

Previously Wallpapered Walls

Common in older homes where wallpaper was fashionable.

Challenges: Adhesive residue, torn drywall paper, texture from old seams

Prep approach:

• Remove all wallpaper first (separate process)
• Clean adhesive residue with TSP
• Skim coat if drywall paper is damaged
• Prime with stain-blocking primer to seal any remaining adhesive

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Common Wall Prep Mistakes to Avoid

These errors ruin otherwise good paint jobs.

Mistake #1: Insufficient Cleaning

You wipe walls with a dry cloth and call it clean. Grease and oils remain, paint doesn't adhere properly, and you see adhesion problems within a year.

Solution: Use proper cleaner (TSP) and wash thoroughly. It's tedious but essential.

Mistake #2: Rushing Repairs

You fill holes and paint the same day. Spackling/joint compound hasn't fully dried and cured. Repairs shrink after painting, creating depressions, or worse, crack.

Solution: Allow full drying time per product instructions. For joint compound, this often means 24 hours between coats.

Mistake #3: Not Priming Repairs

You assume paint will cover repairs. It doesn't. Repaired areas look dull and flat compared to surrounding wall ("flashing").

Solution: Always prime repaired areas before finish painting. Primer seals porous repair materials so finish paint sheen is uniform.

Mistake #4: Inadequate Sanding

You sand repairs lightly and think they're smooth. Under paint and proper lighting, every ridge and bump shows clearly.

Solution: Sand thoroughly until repairs are completely flush and smooth. Check with hand feel and angled light.

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When to Hire Professional Painters

Wall prep is skill-intensive. Some situations call for professionals.

Signs You Should Hire a Pro

• Extensive damage requiring multiple large repairs
• Texture matching you can't execute
• Plaster walls in older homes requiring specialized knowledge
• Lead paint concerns (pre-1978 homes)
• You value time more than DIY cost savings
• You want guaranteed flawless results

At Lamorinda Painting, wall preparation is where we add the most value. We've been prepping Bay Area walls since 2003—walls in older plaster homes, walls with decades of patches, walls with texture mismatches. We know how to make imperfect walls look perfect under fresh paint.

We're fully licensed and insured, and we handle everything from minor repairs to extensive skim coating and texture matching. Your satisfaction is our top priority, and estimates are always free. If you're in Lafayette, Lamorinda, or anywhere in the East Bay, contact us today for a free estimate.

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Frequently Asked Questions

Q: Do I really need to prime before painting?

Yes, in most situations. You must prime repaired areas (spackling, joint compound), stained areas, bare wood, dramatic color changes, and glossy surfaces. The only time you can skip primer is when repainting a clean, previously painted surface in a similar color with quality paint. Even then, spot-priming repairs is mandatory. Primer costs are modest but prevent numerous paint problems.

Q: How long does wall preparation take?

For a typical bedroom (12' x 14') with moderate wall condition, expect 4-8 hours of prep work: cleaning (1-2 hours), repairs (1-2 hours including drying time), sanding (1-2 hours), and priming (1-2 hours). Rooms with extensive damage take longer. Professional painters often spend more time on prep than painting—it's that important for quality results.

Q: Can I paint over small holes without filling them?

No. Paint doesn't fill holes—it just coats them, making them slightly less visible but still noticeable. Holes must be filled with spackling or joint compound, allowed to dry, sanded smooth, and primed before painting. Skipping this step always results in visible imperfections. There are no shortcuts.

Q: What's the difference between spackling and joint compound?

Spackling paste is premixed, dries quickly (2-4 hours), and works well for small holes and minor repairs. Joint compound (also called mud) comes in powder or premixed form, dries slower (24 hours), shrinks less, sands smoother, and works better for larger repairs and skim coating. For small nail holes, use spackling. For anything larger or requiring multiple coats, use joint compound.

Q: Do I need to sand walls before painting?

You need to sand repaired areas to make them flush and smooth. Previously painted walls in good condition don't require full sanding, but glossy surfaces should be lightly scuffed with 150-grit to create tooth for new paint. Any bumps, drips, or imperfections should be sanded smooth. Always sand primer lightly before finish paint for best results.

Q: How do I prep walls that have been smoked in?

Smoke and nicotine residue requires thorough cleaning with TSP or dedicated smoke residue cleaner, followed by oil-based or shellac-based stain-blocking primer (Kilz Original or BIN). Water-based primer won't seal smoke stains adequately. In severe cases, consider professional cleaning before painting. After sealing with stain-blocking primer, finish with any quality paint.

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Conclusion

Wall preparation determines whether your paint job looks professional or amateurish. Clean walls thoroughly, repair all damage properly, prime appropriately, and you create the perfect canvas for beautiful, long-lasting paint results. Cut corners on prep, and your expensive premium paint won't save you—flaws will show, adhesion will fail, and you'll repaint sooner than you should.

Remember the professional ratio: 60-70% prep, 30-40% painting. If you're spending more time painting than prepping, you're probably not prepping thoroughly enough.

At Lamorinda Painting, we've been preparing Bay Area walls expertly since 2003. We're based in Lafayette and serve Lamorinda, the East Bay, and the greater Bay Area. We know that proper preparation is what separates good paint jobs from great ones.

Contact us today for a free estimate. Your satisfaction is our top priority.

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Internal Links:

• Interior Painting Services
• Best Interior Paint Brands
• Drywall Repair Services

External Links:

• Sherwin-Williams Surface Preparation Guide
• Benjamin Moore How to Prime Surfaces

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Images Needed:

• Proper wall cleaning technique
• Filling holes with spackling paste
• Sanding repaired area smooth
• Spot-priming repairs before painting
• Before/after of properly prepped wall