Install Baseboards
Complete the wall-to-floor transition with professionally installed baseboards. Learn cutting techniques for tight corners and clean joints in your converted attic.
Why Proper Baseboard Installation Matters
Baseboards are more than decorative - they cover the expansion gap between flooring and walls, protect wall surfaces from damage, and provide a finished transition that ties the room together. In attic conversions with knee walls and unique angles, properly installed baseboards make the difference between an obviously DIY space and a professionally finished room. Taking time to master coping and mitering techniques pays off in tight joints and a polished appearance.
Tools & Materials Needed
Step-by-Step Installation Guide
Measure and Plan
Thorough planning prevents material waste and ensures efficient installation:
- •Measure all walls and knee walls, recording each length
- •Note the type of corner at each transition (inside, outside, or butt joint)
- •Calculate total linear feet and add 15% for waste and mistakes
- •Plan which pieces will need special cuts for knee wall angles
- •Prime and paint baseboards before installation if using raw wood
Cut Outside Corners
Outside corners require precise 45-degree miter cuts:
- •Set miter saw to 45 degrees for standard outside corners
- •Cut first piece with blade angled to the left, second to the right
- •Dry-fit pieces at corner to check alignment before nailing
- •Use a bevel gauge if corner isn't exactly 90 degrees
- •Apply wood glue to both miter faces before nailing for stronger joint
Pro tip: For the tightest outside corners, cut pieces slightly long and shave them down rather than cutting short.
Cope Inside Corners
Coping creates tighter inside corners than mitering:
- •Cut the first piece square and install it tight to the corner
- •Cut the second piece at 45 degrees to expose the profile
- •Use coping saw to cut along the profile line, back-cutting slightly
- •Test fit and fine-tune with sandpaper or file
- •The coped piece should nest perfectly against the square-cut piece
Important: Practice coping on scrap pieces first. It takes time to master but produces far superior results.
Nail Baseboards in Place
Secure baseboards properly for long-lasting results:
- •Use 15 or 16-gauge finish nails, 2 inches long
- •Nail into studs near the top of the baseboard
- •Add a nail near the bottom into the bottom plate
- •Space nails every 16 inches at stud locations
- •Set nail heads slightly below surface with a nail set
Fill, Caulk, and Touch Up
Finish work makes baseboards look professional:
- •Fill all nail holes with color-matched wood putty
- •Let putty dry and sand smooth
- •Run a bead of paintable caulk along the top edge where baseboard meets wall
- •Smooth caulk with wet finger for clean line
- •Touch up paint over filled holes and caulked seams
Pro Tips
- ✓Start with the longest walls first, using full-length pieces where they'll be most visible
- ✓For knee walls, use a bevel gauge to capture the exact angle before cutting
- ✓Pre-drill near baseboard ends to prevent splitting, especially with MDF
- ✓Consider adding shoe molding along the floor for a more finished look
Frequently Asked Questions
What size baseboards should I use in an attic?▼
For attic conversions with lower ceilings, 3-1/4 to 4-inch baseboards often work best as they provide a finished look without overwhelming the space. If your attic has full-height walls, you can use taller 5-1/4 inch baseboards. Match the style to existing trim in your home for a cohesive look.
How do I install baseboards along angled knee walls?▼
For knee walls, install the baseboard along the floor line where the wall meets the floor. Use a bevel gauge to capture the wall angle for accurate cuts where the baseboard meets full-height walls. You can also add a small piece of quarter-round or shoe molding along the angled knee wall for a finished look.
Should I cope or miter inside corners?▼
Coping is the professional choice for inside corners because it creates tighter joints that won't gap as walls and trim expand and contract. Cut the first piece square to the wall, then cope the second piece to fit against it. Mitering inside corners often results in gaps that are difficult to hide.
Do I need to paint baseboards before or after installation?▼
Paint or prime baseboards before installation for easier coverage and less masking. After installation, fill nail holes, caulk the top edge, and do touch-up painting. Pre-primed MDF baseboards save time since you only need one topcoat after installation.