Drywall Installation
Drywall transforms your ADU from a construction zone into recognizable rooms. This multi-step process—hang, tape, mud, sand, prime—takes 1-2 weeks and creates significant dust. The quality of your drywall finish directly affects your final paint appearance, so it's worth understanding the different finish levels.
Quick Summary
Time needed
1-2 weeks
Cost range
$3-$5 per sq ft
Professional
Drywall contractor
Why Drywall Quality Matters
Drywall is the visible surface of nearly every interior wall and ceiling. Poor drywall work results in visible seams, bumps, and imperfections that paint won't hide. Quality issues become especially apparent in:
- Raking light: Morning/evening sunlight reveals every imperfection
- Flat paint: Shows more imperfections than eggshell or semi-gloss
- Darker colors: More reflective, highlighting surface irregularities
- High ceilings: Overhead seams are highly visible
The Drywall Process: Step by Step
Hanging (Day 1-2)
Drywall sheets are cut to size and fastened to studs and ceiling joists:
- • Standard sheets: 4'x8' or 4'x12' (longer = fewer seams)
- • Ceiling first: Hang ceiling before walls
- • Stagger seams: Avoid continuous vertical seams
- • Screws vs. nails: Screws preferred (less popping over time)
- • Moisture resistant: Green board for bathroom walls near tub/shower
Pro tip: Ceilings are hardest—consider paying for professional hanging even if you DIY the finishing.
Taping (Day 2-3)
Paper or mesh tape covers all seams and corners:
- • Paper tape: Traditional, stronger for corners, requires bedding coat
- • Mesh tape: Self-adhesive, good for flat seams, less durable corners
- • Inside corners: Pre-creased paper tape
- • Outside corners: Metal or plastic corner bead
- • Bedding: First coat of joint compound applied under/over tape
Mudding - First Coat (Day 3-4)
Joint compound ("mud") is applied over tape to fill and smooth seams:
- • All-purpose compound: Good for first coat, easier to sand
- • Setting compound: Dries chemically, faster but harder to sand
- • First coat: Fill tape edges, embed tape fully, cover screw heads
- • Width: Feather 4-6 inches on each side of seam
- • Dry time: 24 hours minimum between coats
Mudding - Second and Third Coats (Days 5-8)
Additional coats build up and feather the joints:
- • Second coat: Wider feathering (8-10 inches), fill low spots
- • Third coat: Even wider (12+ inches), final smoothing
- • Topping compound: Preferred for final coat, smoother finish
- • Light sanding: Between coats to knock down high spots
- • Check with light: Use raking light to find imperfections
Quality note: More coats = better finish. Budget work uses 2 coats; quality work uses 3+. This is where Level 4 vs Level 5 finish quality shows.
Sanding (Day 8-9)
Final sanding creates a smooth surface ready for primer:
- • Grit: 120-150 grit sandpaper or sanding screens
- • Pole sander: For walls and ceilings, easier on your body
- • Technique: Light pressure, circular motions, don't over-sand
- • Edge work: Hand sand corners and edges carefully
- • Dust: Extreme amounts—seal off other areas, wear N95 mask
Dust warning: Drywall dust gets everywhere. Seal HVAC vents, close doors to finished spaces, and plan for thorough cleaning afterward.
Priming (Day 10-11)
Primer seals the drywall and provides a uniform surface for paint:
- • Drywall primer: PVA primer seals porous paper and mud
- • Full coverage: Entire surface, not just mudded areas
- • High-build primer: For Level 5 finish, fills tiny imperfections
- • Light sanding: 220 grit after primer if doing Level 5
- • Spot prime: Touch up any missed spots before paint
Understanding Drywall Finish Levels
The Gypsum Association defines finish levels 0-5. Most residential work is Level 4 or 5:
Level 4 (Standard Residential)
Three coats of joint compound on seams and corners, sanded smooth. Good for most walls with flat or eggshell paint. May show some imperfections under harsh lighting.
Best for: Standard walls, textured ceilings, areas with medium lighting
Level 5 (Premium Finish)
Level 4 plus a skim coat of joint compound over entire surface, providing uniform texture and porosity. Essential for critical lighting conditions or high-gloss paint.
Best for: Areas with harsh lighting, dark/glossy paint, smooth-wall premium finishes. Adds $0.50-$1.00/sq ft.
Recommendation: For ADUs, Level 4 is usually sufficient for walls, but consider Level 5 for ceilings (especially if you have skylights or large windows) and any areas where you plan to use flat or dark paint.
Drywall Cost Breakdown
For a 500 sq ft ADU with approximately 1,500 sq ft of wall/ceiling surface:
Common Drywall Problems to Avoid
Nail/Screw Pops
Fasteners backing out of framing, creating bumps under paint. Caused by lumber shrinkage or improper fastening. Fix by driving new screw nearby and patching.
Visible Seams
Joints showing through paint, especially under raking light. Caused by insufficient coats, narrow feathering, or inadequate sanding. May require re-mudding.
Cracking
Cracks along seams or at corners. Often caused by building movement or insufficient tape/compound. Repair by re-taping or using flexible compound.
Photographing (Flashing)
Mudded areas appearing different from paper face after painting. Caused by skipping primer or different porosity. Always use full-coverage primer.
Frequently Asked Questions
Can I do drywall myself?
DIY drywall is possible but challenging. Hanging is physically demanding, especially ceilings. Finishing requires skill developed over many projects—amateur finishing often looks amateur. Consider DIY hanging with professional finishing, or DIY small projects to learn before tackling an entire ADU.
How long before I can paint after drywall?
Joint compound should cure 24 hours between coats and be fully dry before priming (typically 24-48 hours after final coat depending on humidity). Primer can usually be topcoated within 24 hours. Total time from final sanding to paint: 2-3 days minimum.
Should I add texture to hide imperfections?
Light texture (orange peel, knockdown) can hide minor imperfections and is popular in some regions. Heavy texture (popcorn) is dated and harder to clean/repair. Smooth walls are currently preferred by most designers but require better finishing work. Choose based on your aesthetic preference, not to hide poor workmanship.
What about moisture-resistant drywall in bathrooms?
Use moisture-resistant drywall (green board or purple board) on bathroom walls not in the shower/tub area. Inside showers/tubs, use cement board (Durock, Hardiebacker) as a tile backer—regular drywall will fail. Never use standard drywall in wet areas.
Ready for the Next Step?
With drywall complete and primed, you're ready for the exciting finish phase: paint, flooring, trim, and all the details that make your ADU feel like home.