Coping or Mitering Baseboard Joints: Helping You Choose

Installing Baseboards 87302739
Installing Baseboards. Getty / Image Source

Home remodeling is fraught with choices that balance so perfectly in the middle that it can be hard to know which direction to tip. This is true especially when cutting baseboard inside corners. You can go either of two directions--coping or mitering--and both can seem equally valid:

  • Coping: Cut one baseboard straight at a right angle. Butt it against the wall. Using a coping saw to cope the second baseboard so that its butt-end conforms to the profile of the first baseboard.
  • Mitering: Miter one baseboard at a 45-degree angle. Butt it against the wall. Miter the second baseboard at a 45-degree angle. Butt it against the first baseboard's angle cut.

The interesting thing is that both methods provide exactly the same visual result. Which one is easier? Which produces more stable baseboards?

Experts Weigh In

Many home improvement experts recommend coping. As Taunton's Fine Homebuilding says, "...[M]ost professional carpenters prefer to cope." Carpenters on forums repeatedly recommend coping over mitering.

Why the allure? Gary Katz at This Is Carpentry provides insight; he has a fantastic step by step showing how to cope inside baseboard corners, plus he provides a convincing case for why you should cope. Katz says:

Wood swells and shrinks throughout the year, depending upon seasonal humidity. Coped joints don’t open nearly as much as miters. Cope joints are also faster to install than miters—the pieces of molding don’t have to be cut exactly the right length; in fact, coped material can be cut a little bit long.

Katz also mentions that coped joints never have to be caulked, which anyone--fine builder or otherwise--can tell you is a cheating way of covering up mistakes anywhere in your house, trim-related or not.

Another point to add is that mitered joints can open up even upon installation (not just over the course of years). This happens when you smack in those last two nails closest to the joint. Sometimes they will force the baseboards tighter to the wall, thus widening the joint.

When You Should or Should Not Miter Inside Corners

While all of those things are true, there are strong contextual cases to be made for mitering those inside baseboard corners. Not all conditions need to be present for you to miter your corners:

1. When You Do Not Have Wood Trim

With the onslaught of polyurethane and MDF products on the molding market, shrinkage is a moot point. Poly doesn't expand or contract, and MDF doesn't under normal conditions (but will mushroom up with direct water contact). In fact, even if you have natural wood baseboards such as hemlock, fir, or pine, you can control expansion and contraction by priming all sides of the trim, not just the front side.

2. You Find Miters Easier to Make Than Copes

If you have an electric miter saw, nothing can be easier than locking it to the 45-degree angle, pressing the baseboard against the fence, and sawing down to reveal a nice open angle. By contrast, copes are tricky and take practice. 

3. Miters Can Deal With Out of Square Walls

One argument for coping is that coped trim will accommodate corners that do not meet perfectly at right angles. This is true. But miters can also accommodate corners that are slightly plus or minus 90-degrees. Rather than cutting the trim to 45 degrees, cut it to fit.  Adding or subtracting just one degree can work miracles.

4. Wall Angle and Height Help Hide Imperfections

The visibility of crown moldings means you should step up your game a bit and either cope it or miter it to perfection. But baseboards, being at floor level, are far less visible. Not only that, the joint is slightly shadowed, since this is an inside corner.  

5. Mitering Is Faster

Most homeowners making mitered joints will be finished with the room by the time they have mastered the learning curve of coping joints. Katz says that "[C]oping inside corners is a sign of craftsmanship." True again. But to get true craftsmanship, you should hire a craftsman. Alternatively, you can make the commitment to prioritize fine craftsmanship over other things in your life--and in your house. Many of us need to expedite the trim project so that we can move onto basements that need finishing or house exteriors that need painting. Mitered joints are the quickest way to get this thing done.