Cutting chair rail corners with a miter saw requires precision to achieve seamless joints that enhance your room's aesthetic. The technique varies based on whether you're dealing with an inside or outside corner, or simply butting against a frame.
Using your miter saw, cut the first piece of moulding. For optimal results and a professional finish, understanding the correct angles is crucial.
Understanding Chair Rail Corner Types
When approaching chair rail installation, you'll primarily encounter two types of corners:
- Inside Corners: Where two walls meet, forming an inward angle (typically 90 degrees).
- Outside Corners: Where two walls meet, forming an outward angle (typically 90 degrees).
Essential Miter Saw Settings for Chair Rail
The miter saw angle settings are critical for cutting chair rail effectively. Here's a breakdown of the common cuts and the specific guidance from the provided reference:
| Corner Type | Miter Saw Angle Setting (Each Piece) | Notes & Guidance from Reference |
|---|---|---|
| Outside Corner | 45 degrees | For all outside corners, cut at a 45-degree angle. This creates a clean, outward-facing joint when the two pieces meet. |
| Inside Corner (Mitered) | 45 degrees | While the reference states "you will be using 90-degree angles for inside corners," this typically refers to the wall angle itself. For a mitered joint on a 90-degree inside corner, each piece of chair rail is cut at a 45-degree angle. However, for inside corner joints, we recommend coping over mitering, as this results in a cleaner, smoother seam. This is a strong recommendation for a superior finish. |
| Butt Joint (Against Frame) | 90 degrees (straight cut) | Used for those that butt against door or window frames. A straight 90-degree cut ensures a flush fit against the flat surface. |
Cutting Inside Chair Rail Corners
Inside corners are where walls meet at an inward angle. While traditional mitering is possible, coping is often preferred for a more durable and seamless finish.
The Mitered Approach (Standard)
For a traditional mitered inside corner on a standard 90-degree wall, you will cut two pieces of chair rail, each at a 45-degree angle.
- First Piece: Set your miter saw to a 45-degree angle (e.g., 45 degrees to the left for the right-hand piece). Make the cut.
- Second Piece: Set your miter saw to the opposite 45-degree angle (e.g., 45 degrees to the right for the left-hand piece). Make the cut.
- When joined, these two 45-degree cuts will form a 90-degree corner. The main challenge with mitered inside corners is that slight imperfections in the wall angle or house settling can cause gaps to appear over time.
The Recommended Coped Approach
As highlighted by the reference, for inside corner joints, we recommend coping over mitering, as this results in a cleaner, smoother seam. Coping involves cutting a profile into one piece of chair rail that perfectly matches the profile of the adjacent piece.
- First Piece (Butt Cut): Cut the first piece of chair rail with a straight 90-degree (butt) cut, allowing it to butt directly into the corner of the wall.
- Second Piece (Cope Cut):
- Cut the second piece with an initial 45-degree miter cut, as if you were going to miter the joint.
- Using a coping saw (or jigsaw for rough cut, then coping saw for fine work), carefully cut along the exposed profile created by the 45-degree miter. You are essentially removing the back portion of the trim, leaving only the face profile.
- This "coped" edge will then fit snugly against the face of the first piece, creating a joint that hides minor wall imperfections and is less prone to gapping over time.
Cutting Outside Chair Rail Corners
Outside corners are where walls meet at an outward angle. These are typically cut with mitered joints for a clean, finished look.
- Measure: Measure the length of the wall section leading up to the outside corner.
- Angle Setup: Set your miter saw to a 45-degree angle.
- First Piece: Position the chair rail so the longer point of the miter cut will be on the outside edge of the trim (the part facing into the room). Make your cut.
- Second Piece: Repeat the process for the second piece, ensuring the 45-degree cut is mirrored, so the two pieces will fit together perfectly to form a 90-degree outside corner. Remember, cut at a 45-degree angle for all outside corners.
Cutting Against Door or Window Frames (Butt Joints)
For sections of chair rail that terminate against a door casing or window frame, a simple butt joint is used.
- Measure: Measure the exact distance from the last joint to the edge of the frame.
- Cut: Set your miter saw to a 90-degree angle (a straight cut). Make the cut cleanly.
- This creates a flush, neat finish against the flat surface of the frame.
Practical Tips for Perfect Chair Rail Corners
- Test Cuts: Always make test cuts on scrap pieces of chair rail to verify your miter saw settings and ensure the angles are correct before cutting your actual pieces.
- Dry Fit: Before permanent installation, dry-fit your cut pieces to check for gaps or misalignments. Minor adjustments can be made with sandpaper or a block plane.
- Cut Slightly Long: It's often better to cut pieces slightly long and trim them down in small increments until you achieve a perfect fit. You can always take more off, but you can't add it back.
- Account for Wall Imperfections: Walls are rarely perfectly square. For mitered joints, use an angle finder to measure the exact wall angle and divide it by two for your miter saw setting. However, coping largely negates issues from imperfect inside wall angles.
- Safety First: Always wear safety glasses and follow all safety guidelines for your miter saw.
By following these techniques, especially considering the benefits of coping for inside corners as recommended, you can achieve professional-looking chair rail installations.
