How to Cope Baseboard Inside Corners
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Coping baseboard is a functional skill melding function and artistic craftsmanship. Learning how to cope baseboard the right way creates the perfect corner every time. This technique outlined below is perfect for corners that are both square and not square–as many are! An airtight seam is a subtle finish to a room you take for granted.
Compare a finely coped inside corner to a gappy one. When you look at a shoddy corner you either:
- think it looks sloppy or
- take out your caulk gun and (if the baseboard is painted) start thinking about dreaded painting.
If it is stained baseboard you are stuck with option #1 or get a new piece and try out your skills with the following directions.
Tools needed for this project:
- Miter saw
- Quick-grip clamps or C clamps
- Jigsaw or coping saw
- Dremel, assorted shaped files (I recommend at least one flat, circular and triangular), or 100 grit sandpaper
Start off right by coping against a perfectly level, secured perpendicular butted end.
Before you start make sure butted edge baseboard you are coping against is true. Normally drywall is hung horizontally so the bottom edge curves inwards towards the wall.
You can see the little horizontal shadow of drywall curve as it starts to curve inwards.
When baseboard is attached a nail gun can make a baseboard suck into that void. A small shim or a protruding drywall screw set at the level point will keep the baseboard true. This way you are not accounting for an angle, with this particular baseboard, on the bottom three inches where it is supposed to be coped straight. Not only is a angled baseboard harder to cope, you’ll have a gap at the top of the baseboard.
You don’t want to have to deal with a baseboard at this angle or the gap at the top.
Make a 45 degree angle cut.
Pull out your chop saw and set it at a 45-degree angle.
Next, cut where the outside edge is shorter than the backside edge.
That beautiful curvy white edge is the secret to making a precise cope.
Why?
The result of the angle cut is the EXACT line you want to cut along with a jigsaw or a coping saw.
You don’t have to mark it if it is easy enough to see, like it is on this pre primed MDF baseboard. If is more difficult, like on a stained wood, pinpoint the edge with pencil. Make that edge easy to see and pencil is easy enough to wipe off later if there is any excess.
Start coping.
You don’t want to just make the final cut perpendicular. It should be angled slightly backwards a few degrees so that the length of the board is right on the coped edge.
The one place you DO want a perpendicular cut is along the top edge where the coped edge meets the butted piece.
An angle right there would create an unfortunate gap.
Next break out your tool of choice: a jigsaw or a coping saw. You may enjoy wielding a power tool, making quick work of the cut. However a coping saw–which is manually powered–is much more forgiving when you are first starting out on this project.
Coping saw.
Use the coping saw to cut along the guide at an angle.
The one exception to this step: you already have your miter saw out–adjust it back to a 20 degree angle or so and use it to cope the straight part of the base.
I also used a spacer to get a better cut from the blade.
Depending on the curve on the baseboard you may not be able to cope the line in one effort. You don’t want to manhandle the coping blade by bending it. Instead, back it out and approach it from a different angle.
Dry fit the cope.
The coped edge may need small adjustments. If it is just a hair too long you can easily break out file, a dremel (DAMN CAREFULLY!), or some 100 grit sandpaper.
Personally, I like using a handful of files–flat, triangular and a couple different sized circular files.
Each file has its own use for straightaways (flat file), curves (circular file), or angular shapes (triangle file).
Here I am using the larger circular file.
…and the smaller circular file.
Trimming down is easy because the leading edge is cut backwards leaving a small surface area at the corner.
Compare this against a miter cut where there is a huge amount of surface area along the cut edge. Small adjustments are easily made on a coped edge in comparison to a miter cut.
If you get a little too carried away with the file or dremel you can always go back to step two and cut another 45 degree angle. This is why you should leave the baseboard a little longer than necessary if you are coping in place and cut the opposite end down to size after your dry fit is complete.
No matter which tool you choose to make the final cope, take some scrap baseboard and practice a few cuts before taking on a larger piece. Or start out on the inside of closets before committing to more obvious locations.
Ahhh. Perfection!
Extra tips.
If you don’t feel too confident about sawing right along the guideline you can always saw a little long then file it down slowly, but surely towards the leading edge.
Don’t get greedy if you opt to use the miter saw to cut the straightaway. You may have noticed in the final picture above, I was attempting to use the miter saw to cut the straight part, stopped the saw, and the saw dipped. Instead, I should have kept the blade moving continuously down and up so that it did not lurch downward, like I did in the good sample photo above.
It really is easy to adjust a coped baseboard. As you can see from the backside view, you only have to file down a little of the leading edge to perfect the joint.
Worst case scenario: if your practice inside corners are becoming your worst nightmare consider going with a simpler style baseboard. A flat 1″ x 4″ baseboard is a classic and modern. Coping is 100% doable with a simple chop of a miter saw.
