How to Install Quarter Round Molding
Quarter round covers the expansion gap and gives your flooring a finished, professional look. Use our calculator to estimate materials needed and costs.
📏 Quarter Round Calculator
Tip: Add up all wall lengths in the rooms receiving new trim
Molding Type
Finish Type
Include in Estimate
Materials Needed
Quick Summary
Time needed
3-4 hours
Cost
$50-150
Difficulty
Medium
Why Quarter Round Matters
That 1/4-inch expansion gap around your floor looks unfinished and collects dust. Quarter round (or shoe molding) covers the gap while still allowing the floor to move freely. It's the final touch that transforms an installation from "DIY" to "professional."
Critical Rule: Never nail quarter round to the floor. Always nail it to the baseboard or wall. The floor must remain free-floating to expand and contract. Nailing trim to the floor defeats the purpose of the expansion gap.
Materials and Tools Needed
Materials
- • Quarter round or shoe molding (measure linear feet needed)
- • Finish nails (1.5-inch to 2-inch, 18-gauge)
- • Wood filler or putty
- • Caulk (paintable if painting)
- • Paint or stain to match
Tools
- • Miter saw
- • Finish nailer (or hammer and nail set)
- • Tape measure
- • Pencil
- • Coping saw (for inside corners)
- • Caulk gun
Step-by-Step Installation
Step 1: Measure and Purchase Materials
Measure the perimeter of all rooms receiving quarter round. Add 10-15% for waste from cutting corners.
Buying Tip: Quarter round comes in 8-foot lengths typically. Buy prefinished if you want to skip painting. Match your baseboard color - white, oak, or paint-grade pine are most common.
Step 2: Cut Outside Corners
Outside corners (walls that stick out into the room) use 45-degree miter cuts that meet to form a 90-degree corner.
Miter Cut Process:
- 1. Measure wall length from corner to corner
- 2. Cut first piece with 45-degree right miter
- 3. Cut second piece with 45-degree left miter
- 4. Test fit - corners should meet perfectly at 90 degrees
- 5. Adjust if needed (walls aren't always exactly 90 degrees)
Step 3: Nail to Baseboard (Not Floor!)
This is the most important step. Nails must go into the baseboard or wall studs, never into the flooring.
Why Not the Floor? Floating floors expand and contract with humidity. Nailing trim to the floor anchors it in place, preventing movement and causing buckling or gaps. The floor must remain free-floating.
Nailing Technique:
- • Place quarter round against floor and baseboard
- • Angle nail gun or hammer slightly upward (about 30 degrees)
- • Nail every 12-18 inches
- • Aim for baseboard or wall, not down into floor
- • Use 1.5-inch to 2-inch finish nails (18-gauge)
- • Sink nails slightly below surface with nail set
Step 4: Fill Nail Holes and Gaps
Make nail holes disappear and create seamless-looking corners with filler and caulk.
- • Fill nail holes with wood filler or putty
- • Let dry completely (usually 30 minutes)
- • Sand smooth with fine-grit sandpaper
- • Caulk gap between quarter round and baseboard if visible
- • Smooth caulk with wet finger or tool
- • Let everything dry before painting
Frequently Asked Questions
Do I nail quarter round to the floor or baseboard?
Always nail quarter round to the baseboard or wall, NEVER to the floor. Flooring needs to expand and contract with humidity changes. If you nail trim to the floor, you prevent this movement and risk buckling or gaps. Angle nails slightly upward into the baseboard.
What's the difference between quarter round and shoe molding?
Quarter round has a perfect 90-degree arc (quarter of a circle). Shoe molding has an elongated profile - taller than it is wide. Shoe molding hugs the floor better when baseboards aren't perfectly flat. Functionally they're interchangeable. Quarter round is more common and usually cheaper.
How much quarter round do I need?
Measure the perimeter of all walls in the room (total of all wall lengths). Add 10-15% for waste from miter cuts and mistakes. Quarter round typically comes in 8-foot lengths, so divide your total by 8 to determine how many pieces to buy.
Ready for the Next Step?
With quarter round installed, it's time to clean your new floor thoroughly and prepare it for use.