Maintenance script at 20:15, 23 March 2026

2026-03-23T20:15:39Z

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'''Surface preparation''' is the process of cleaning, repairing, and priming surfaces before painting. Professional painters agree that '''80% of a paint job's quality comes from preparation''' — cutting corners on prep leads to [[Paint Peeling|peeling]], [[Paint Bubbling|bubbling]], poor adhesion, and premature failure.

== Why Prep Matters ==

Paint is only as good as the surface beneath it. No amount of premium paint can compensate for:
* '''Dirt and grease''' — paint won't bond to contaminated surfaces
* '''Loose or flaking paint''' — new paint peels with the old
* '''Holes, cracks, and damage''' — imperfections telegraph through new paint
* '''Glossy surfaces''' — smooth, shiny surfaces reject new paint
* '''Moisture''' — trapped moisture causes [[Paint Bubbling|bubbling]] and [[Paint Peeling|peeling]]

== The Prep Process ==

=== Step 1: Clean ===

{| class="wikitable" style="width: 100%;"
|-
! Surface !! Cleaning Method !! Notes
|-
| General interior walls || Damp cloth or dry Swiffer || Remove dust, cobwebs, fingerprints
|-
| Kitchen walls || TSP solution (trisodium phosphate) || Cuts grease and cooking film
|-
| Bathroom walls || Mildew remover, then rinse || Kill mold/mildew before painting
|-
| Smoker's home || TSP wash, then shellac [[Paint Primer|primer]] || Nicotine bleeds through latex paint
|-
| [[Exterior Painting|Exterior surfaces]] || Power wash (1,500-2,500 PSI) || Allow 48-72 hours drying after
|-
| New drywall || Wipe with damp cloth || Remove joint compound dust
|-
| Previously glossy surfaces || TSP wash or liquid deglosser || Creates tooth for paint adhesion
|}

=== Step 2: Repair ===

==== [[Drywall Repair]] ====
* '''Nail holes''': Fill with lightweight spackle, let dry, sand smooth
* '''Small holes (up to 1/2")''': Apply spackle in thin layers, building up
* '''Medium holes (1/2" - 4")''': Use self-adhesive mesh patch + joint compound
* '''Large holes (4"+)''': Cut drywall patch, install with backing boards, tape and mud
* '''Cracks''': Widen slightly with utility knife, fill with flexible joint compound
* '''Nail pops''': Drive new screw 2" above or below, countersink, fill both holes
* '''Skim coating''': Apply thin layer of joint compound to severely damaged areas

==== Wood Repair ====
* Fill nail holes with wood filler (stainable if staining, any type if painting)
* Repair splits and cracks with wood epoxy for strength
* Replace rotted sections — do not paint over rot
* Glue loose joints and molding
* Fill gaps between trim and wall with [[Caulking|paintable caulk]]

=== Step 3: [[Sanding|Sand]] ===

{| class="wikitable"
|-
! Grit !! Use
|-
| '''60-80''' || Removing old paint, heavy material removal
|-
| '''100-120''' || Smoothing repairs, general prep
|-
| '''150''' || Standard sanding before painting
|-
| '''180-220''' || Between coats, fine finishing
|-
| '''320+''' || Ultra-fine finishing for [[Painting Cabinets|cabinets]] and furniture
|}

'''Sanding guidelines:'''
* Always sand '''with the grain''' on wood
* Use a [[Sanding|sanding sponge]] for contoured trim and molding
* Use a sanding block or pole sander for flat walls
* Feather edges where old paint meets bare surface
* Remove all sanding dust before painting — tack cloth or damp rag

=== Step 4: [[Caulking|Caulk]] ===

Apply '''paintable acrylic latex caulk''' to:
* Gaps between trim and walls
* Gaps between trim pieces (mitered corners)
* Cracks where different materials meet
* Around window and door frames

'''Technique:'''
# Cut caulk tube tip at 45° angle, small opening (1/8")
# Apply steady, even bead along the gap
# Smooth immediately with a wet finger or caulk tool
# Wipe excess with a damp rag
# Let dry before painting (1-2 hours for latex caulk)

'''Never caulk:'''
* Between baseboards and floors (this gap allows for expansion)
* Wood joints that need to flex seasonally
* Gaps over 1/4" wide (use backer rod first)

=== Step 5: [[Masking and Taping|Mask and Tape]] ===

* Apply painter's tape to ceiling lines, trim edges, and around fixtures
* Use '''FrogTape''' for the sharpest lines or '''3M ScotchBlue''' for general use
* Press tape edges firmly with a putty knife for a seal
* Apply tape to clean, dry surfaces only
* Extend drop cloths up to baseboards

=== Step 6: [[Paint Primer|Prime]] ===

{| class="wikitable" style="width: 100%;"
|-
! Situation !! Primer Type !! Why
|-
| New drywall || PVA drywall primer || Seals porous surface, even absorption
|-
| Bare wood || Oil-based or shellac primer || Seals grain, blocks tannin bleed
|-
| Stains (water, smoke, crayon) || Shellac-based (Zinsser BIN) || Only shellac reliably blocks all stains
|-
| Glossy surfaces || Bonding primer || Chemical adhesion to slick surfaces
|-
| Dramatic color change || Tinted primer (match final color) || Reduces finish coats needed
|-
| Metal surfaces || Rust-inhibiting primer || Prevents corrosion under paint
|-
| [[Painting Concrete|Concrete/masonry]] || Masonry primer || Handles alkalinity and porosity
|-
| Patched/repaired areas || Matching primer || Prevents "flashing" (sheen differences)
|}

== Prep Checklists by Surface ==

=== Interior Walls (Drywall) ===
# Wipe or dust walls
# Fill holes and cracks with spackle
# Sand repairs smooth (150-grit)
# Caulk gaps between trim and walls
# Wipe away dust
# Prime bare spots and repairs
# Tape and mask

=== Interior Trim (Wood) ===
# Clean/degrease
# Fill nail holes with wood filler
# Caulk gaps
# Sand entire surface (150-grit for adhesion)
# Wipe with tack cloth
# Prime bare wood and repairs
# Sand primer lightly (220-grit)

=== [[Exterior Painting|Exterior Siding]] ===
# Power wash
# Dry 48-72 hours
# Scrape [[Paint Peeling|loose paint]]
# Sand and feather edges (80-120 grit)
# Replace rotted wood
# Caulk all gaps around windows, doors, trim
# Prime bare wood and repairs with oil-based exterior primer

=== [[Painting Cabinets|Kitchen Cabinets]] ===
# Remove doors, drawers, hardware
# Label everything
# Degrease with TSP (critical — kitchen grease prevents adhesion)
# Sand (120-grit, then 150-grit)
# Fill grain with wood filler (optional, for ultra-smooth finish)
# Sand filler (220-grit)
# Apply bonding primer or shellac primer
# Sand primer (220-grit)

=== [[Painting Metal|Metal Surfaces]] ===
# Remove loose rust with wire brush or sandpaper
# Clean with mineral spirits to remove oil/grease
# Apply rust-converting primer to any remaining rust
# Apply metal-specific primer

== Frequently Asked Questions ==

=== How much time should I spend on prep vs. painting? ===

Plan for prep to take '''50-75% of total project time'''. For a typical room repaint with minor repairs, expect 3-4 hours of prep and 2-3 hours of painting. For extensive repairs, [[Paint Stripping|paint stripping]], or heavy damage, prep can take days while the actual painting takes hours. Professional painters understand this — it's why the best painters spend most of their time preparing surfaces. Rushing prep to start painting sooner always results in a worse finished product.

=== Can I skip priming if I use paint-and-primer-in-one? ===

'''Paint-and-primer combinations''' work well for routine repaints over similar colors on previously painted surfaces in good condition. However, you '''still need dedicated [[Paint Primer|primer]]''' for: new/bare drywall, bare wood, stain blocking, dramatic color changes, glossy surfaces, and any type of repair work. Paint-and-primer combos cannot match the sealing, adhesion, and stain-blocking properties of dedicated primers. When in doubt, prime separately.

=== Do I need to sand between coats of paint? ===

For walls, '''no''' — light [[Sanding|sanding]] between coats is unnecessary if you're using the same paint type and recoating within the recommended window. For [[Painting Trim|trim]], [[Painting Cabinets|cabinets]], and fine finish work, '''yes''' — lightly sanding between coats with 220-grit removes nibs, [[Brush Marks|brush marks]], and dust particles, creating a smoother foundation for the next coat. This is the difference between a good finish and a professional finish. Always remove sanding dust with a tack cloth before applying the next coat.

=== What happens if I skip surface preparation? ===

Skipping prep leads to '''poor adhesion''' (paint won't stick properly and will [[Paint Peeling|peel]] within months), '''uneven coverage''' (patched areas and different surface textures absorb paint differently, creating visible inconsistency), '''stain bleed-through''' (water stains, smoke damage, and tannin reappear through the new paint), and '''a rough or bumpy finish''' (dust, debris, and unfilled imperfections telegraph through the paint). You'll eventually need to strip everything and start over — costing more than doing it right the first time.

[[Category:Surface Preparation]]
[[Category:Painting Techniques]]
[[Category:DIY Painting]]

Surface Preparation - Revision history

Maintenance script at 20:15, 23 March 2026