Hang Drywall on Knee Walls
Complete your attic's wall surfaces with proper drywall installation on knee walls and partitions. Master the techniques for short walls and angled transitions.
Why Knee Wall Installation Matters
Knee walls are the short vertical walls that connect your floor to the sloped ceiling in an attic conversion. They define the usable living space and create the transition between the room and the unconditioned triangular attic areas behind them. Proper drywall installation on knee walls requires careful attention to the angled cuts where walls meet ceiling slopes - this joint is visible and must be crisp. Knee walls also often house outlets, switches, and HVAC registers that need precise cutouts. While easier than ceiling work, knee walls present unique challenges from their short height, multiple angles, and the need to work in tight spaces. Quality installation here contributes significantly to the finished room's appearance.
Tools & Materials Needed
Step-by-Step Guide
Plan Panel Layout
Determine the most efficient way to cover your knee walls:
- - Best for walls 4 feet or shorter
- - One panel can cover floor to ceiling
- - Fewer seams to tape
- - Easier to handle in tight spaces
- - Better for walls over 4 feet
- - Horizontal seams are easier to tape
- - More structural strength across studs
- - Standard approach for partition walls
Measure Knee Wall Dimensions
Knee walls often have varying heights - measure carefully:
- -Measure height at each stud location (heights may vary)
- -Use bevel gauge to capture the angle where wall meets ceiling
- -Note outlet, switch, and register locations
- -Mark stud locations on floor and ceiling for reference
- -Account for 1/2" gap at floor (baseboard will cover)
Tip: Make a cardboard template for angled cuts - test fit before cutting expensive drywall.
Cut Panels with Angled Tops
The angled cut where knee wall meets ceiling requires precision:
- Transfer bevel gauge angle to drywall panel
- Mark cut line with straightedge or chalk line
- Score face paper deeply with utility knife
- Snap panel along score line
- Cut back paper to release
- Smooth edge with rasp if needed
- Test fit before final installation
For complex angles: Use a roto-zip or drywall saw for curves or compound angles that can't be scored and snapped.
Cut Openings for Electrical
Mark and cut precise openings for outlets, switches, and registers:
- -Measure from fixed reference points (floor, corner, adjacent panel)
- -Use electrical box as template - trace outline
- -Cut 1/4" larger than box on all sides
- -Use drywall saw or roto-zip for cutouts
- -Test fit panel before fastening permanently
Install Wall Panels
Fasten panels systematically:
- Position panel tight against ceiling drywall
- Lift panel 1/2" off floor (use drywall foot lever)
- Check that edges fall on stud centers
- Drive screws at top corners to hold position
- Work down and across, fastening to each stud
- - Use 1-1/4" screws for 1/2" drywall
- - Space screws 12" apart in field
- - Space screws 8" apart at edges
- - Keep 3/8" from edges, 1" from corners
- - Dimple slightly below surface
Handle Wall-to-Ceiling Transition
Create clean joints where knee walls meet sloped ceilings:
- - Wall panel butts against ceiling panel
- - Leave 1/8" gap for tape and mud
- - Tape as inside corner during finishing
- - Flexible corner bead for odd angles
- - Install metal corner bead
- - Nail or crimp bead in place
- - Mud and feather for smooth edge
- - Use flexible bead for non-90° angles
Complete Partition Walls
Install drywall on full-height partition walls:
- -Run panels horizontally on walls over 4 feet
- -Install top row first, tight to ceiling
- -Bottom row lifts to butt against top row
- -Stagger vertical seams from row to row
- -Frame door openings with corner bead
Pro Tips
- -Use a drywall foot lever (or scraps under panel) to lift panels off floor while positioning
- -Cut panels on the floor or a cutting table - working overhead wastes energy
- -Pre-cut all pieces for a wall before starting installation - faster workflow
- -Have extra screws ready - you'll use more than expected on walls with many studs
Frequently Asked Questions
Should I install drywall horizontally or vertically on knee walls?▼
For typical knee walls (4-5 feet high), vertical installation often works best because one panel covers floor to ceiling transition with minimal cuts. Horizontal installation is preferred for walls over 4 feet where it reduces the number of seams. The key is minimizing seams and waste - sketch both layouts to see which works better for your specific wall dimensions.
How do I cut drywall for the angled top where knee wall meets ceiling?▼
Measure the angle using a bevel gauge or digital angle finder. For most roof pitches, use a T-bevel to transfer the angle to your drywall. Mark the cut line, then score with a utility knife and snap. For complex angles, make a cardboard template first. Leave 1/8 inch gap at the ceiling junction - it'll be covered by mud and tape.
What thickness drywall should I use on knee walls?▼
Use 1/2 inch drywall for knee walls (unlike ceilings which need 5/8 inch). Standard walls don't experience the same sagging forces as ceilings, so the lighter 1/2 inch panels work fine and are easier to handle in tight attic spaces. Use moisture-resistant drywall in bathrooms and near plumbing.
Do I need to drywall the back side of knee walls?▼
No, but you should cover the back side with something to protect the insulation and create an air barrier. Options include: rigid foam board (adds R-value), house wrap or building paper (air barrier), or drywall if you want a finished storage area. The back side faces unconditioned attic space behind the knee wall.