Step 41 of 44Systems & Interior Phase

Interior Paint & Finishes

This is where your ADU transforms from a construction project into a beautiful living space. Interior finishes—paint, flooring, baseboards, trim, and doors—define the look and feel of your unit. Plan on 2-3 weeks for this phase, and budget carefully since finishes can range from economical to premium.

Quick Summary

Time needed

2-3 weeks

Cost range

$5,000-$15,000

Professionals

Painter, flooring installer

The Right Order for Interior Finishes

Installation sequence matters. Following the right order prevents damage and rework:

  1. 1
    Prime walls and ceilings

    Already done after drywall (covered in previous step)

  2. 2
    Paint ceilings first

    Easier to cut in walls later; drips don't matter yet

  3. 3
    Paint walls

    Two coats typically; don't need to cut in at floor yet

  4. 4
    Install flooring

    After painting to prevent damage; leave expansion gap at walls

  5. 5
    Install baseboards and trim

    Covers flooring expansion gap; goes over painted walls

  6. 6
    Install interior doors

    After flooring so clearance is correct

  7. 7
    Paint/caulk trim and doors

    Final paint touches, caulk gaps for clean finish

Interior Paint Guide

Paint Sheen Selection

Different sheens suit different areas:

  • Flat/Matte: Best hide for imperfections, hardest to clean. Use on ceilings.
  • Eggshell: Slight sheen, cleanable, hides minor imperfections. Best for living areas, bedrooms.
  • Satin: More sheen, very cleanable. Good for hallways, kids' areas, kitchens.
  • Semi-gloss: Highly durable and cleanable. Use in bathrooms, kitchens, on trim.
  • High-gloss: Very shiny, shows every flaw. Use only on doors/trim for dramatic look.

Paint Quality and Coverage

Quality paint costs more upfront but saves in the long run:

  • Budget paint ($25-35/gallon): Requires 3+ coats, fades faster, harder to touch up
  • Mid-grade ($40-55/gallon): Good coverage in 2 coats, decent durability
  • Premium ($55-80/gallon): One-coat coverage possible, best durability, easiest touch-ups

Math tip: Premium paint at $70/gallon covering 400 sq ft in one coat costs $0.175/sq ft. Budget paint at $30/gallon needing three coats costs $0.225/sq ft plus extra labor. Premium often wins on total cost.

Color Selection Tips

  • Light colors: Make small ADUs feel larger and brighter
  • Warm whites: More inviting than stark white (try off-whites with warm undertones)
  • Consistent palette: Use 2-3 coordinating colors throughout for cohesion
  • Test samples: Paint 12"x12" squares on walls; colors look different at scale
  • Consider lighting: North-facing rooms look cooler; south-facing look warmer

Flooring Options Compared

Luxury Vinyl Plank (LVP)

Most Popular for ADUs

Waterproof, durable, affordable, and available in realistic wood looks. Easy DIY installation.

Cost installed

$3-$6 per sq ft

Best for

Entire ADU including bathrooms

WaterproofScratch resistantDIY friendly15-25 year lifespan

Engineered Hardwood

Real wood top layer over plywood core. More dimensionally stable than solid hardwood, can be refinished 1-2 times. Premium look and feel.

Cost installed

$6-$12 per sq ft

Best for

Living areas, bedrooms (not bathrooms)

Real woodRefinishablePremium feel25-50 year lifespan

Laminate Flooring

Photographic wood image over fiberboard core. Budget-friendly but not waterproof (water-resistant options exist). Can look artificial in bright light.

Cost installed

$2-$5 per sq ft

Best for

Budget projects, dry areas only

Budget friendlyDIY friendlyNot waterproof10-20 year lifespan

Tile (Porcelain or Ceramic)

Waterproof and extremely durable. Cold underfoot (consider radiant heat). Higher installation cost due to labor intensity.

Cost installed

$8-$15 per sq ft

Best for

Bathrooms, possibly kitchens

WaterproofExtremely durableCold underfoot50+ year lifespan

ADU recommendation: LVP throughout (including bathroom) is the most practical choice for most ADUs. It's waterproof, durable, looks great, and keeps costs reasonable. Consider engineered hardwood if you want a premium feel and have budget flexibility.

Baseboards and Trim

Trim covers expansion gaps and transitions while adding architectural detail:

Baseboard Options

  • MDF (painted): $0.50-$1.50/ft - Smooth, takes paint well, not moisture resistant
  • Primed pine: $1-$2/ft - Real wood, paintable, more durable than MDF
  • Stain-grade oak: $2-$5/ft - For stained (not painted) applications
  • PVC/vinyl: $1-$3/ft - Waterproof, good for bathrooms

Height matters: 3-1/4" is standard, 5-1/4" looks more substantial, 7-1/4" makes a statement.

Other Trim Elements

  • Door casing: Frames around interior doors (typically matches baseboards)
  • Window casing: Frames around windows (match door casing)
  • Crown molding: Optional ceiling trim (adds cost but elevates look)
  • Shoe molding: Small quarter-round at floor/baseboard junction

Interior Doors

ADUs typically need 3-6 interior doors: bedrooms, bathroom, closets, possibly utility.

Door TypeCost (prehung)Notes
Hollow core$80-$150Lightest, least sound blocking, most affordable
Solid core$150-$300Better sound blocking, substantial feel
Solid wood$300-$800+Premium, can be stained, heaviest
Barn/sliding$200-$500Space-saving, trendy look, less privacy

ADU tip: Use solid core doors for bedrooms and bathrooms (better sound privacy), hollow core for closets. Barn doors look great but don't seal well for bathrooms unless you add privacy features.

Interior Finishes Cost Summary

Estimated costs for a 500 sq ft ADU:

Paint (walls, ceilings, trim)$1,500-$3,500
Flooring (LVP throughout)$1,500-$3,000
Baseboards and trim$800-$1,500
Interior doors (4-5 doors)$800-$2,000
Door hardware$150-$400
Total Range$4,750-$10,400

Note: Engineered hardwood flooring would add $1,500-$3,000 to these estimates.

Frequently Asked Questions

Can I paint and install flooring myself?

Painting is one of the most DIY-friendly projects—with proper prep, most homeowners can achieve good results. LVP and laminate flooring are also DIY-friendly (click-lock installation). Tile and hardwood are more challenging and typically benefit from professional installation. Trim work requires precise cuts and coping skills.

What's the best flooring for rental ADUs?

LVP is ideal for rentals—it's waterproof (handles spills and pet accidents), scratch resistant, easy to clean, and affordable to replace if damaged. Choose a middle-grade product ($3-5/sq ft) with a thick wear layer (12+ mil) for best durability. Avoid carpet (stains, allergens) and light-colored grout (staining).

How do I choose paint colors for a small space?

Light, neutral colors make small ADUs feel larger. Stick to warm whites, light grays, or soft warm neutrals. Use the same color throughout (or limit to 2-3 coordinating colors) for visual flow. Add interest through furniture and accessories rather than wall colors. Test samples in your actual space—lighting dramatically affects color.

Should baseboards match door trim?

Yes, using matching (or at least coordinating) baseboards and door/window casing creates a cohesive look. Most ADUs use the same profile and paint color for all trim. White or off-white trim is classic and works with any wall color. Matching trim to walls creates a modern, seamless look but requires more careful installation.

Ready for the Next Step?

With interior finishes complete, your ADU is starting to look like a real home. Next up is the kitchen installation—cabinetry, countertops, and appliances.

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