Installing Baseboard and Chair Rail using Coped Joints

by luke on April 26, 2013

Baseboard and Chair Rail: Using a Coping Saw

Dogfish Head IPAFinish work is often the most rewarding part of the any project. Although there is often frustration with any carpentry project, if you use the correct techniques and have the right tools available you’ll do fine. Expect to make mis-cuts, and to use your (planned) scrap to practice making coped joints.

Our suggested beer pairing (upon successful completion) is a 6 pack of Dogfish Head 60min IPA, Americas Favorite IPA.

What you will need:

  1. Miter saw- power (60+ tooth blade) or hand saw is OK as long as you can make clean 45 degree cuts
  2. Coping saw- with an extra blade (blade should cut on the “push” stroke. This will reduce chipping of finish or enamel when coping.)
  3. Level(s)- Depending on how long your runs are could be 10”- 6ft
  4. A work table for making coped joints
  5. 120 grit sand paper (optional)
  6. Glue (outside corners)
  7. Wood filler (for nail holes)
  8. Tape measure
  9. Pencils
  10. Finish nails/brads (Outside corners: 18ga 1 1/4″. General fastening: 15ga 2″ are common)

What will be nice to have:

  1. 10” Sliding Miter Saw w/stand
  2. Table Saw
  3. Random orbit sander w/ 180 grit
  4. Finish Nailer/Brad Gun with 1 ¾  – 2 ½ inch nails for attaching trim to walls.

Getting Started

Once you begin, you’ll be making a lot of trips between your work/cutting area and your installation area. You’ll definitely want to minimize walking distance as much as possible.

Coping joints has been a standard practice of finish carpenters for hundreds of years, it seems that with the invention of the “box store” and the availability of miter saws, standard practice has become two 45-degree angles paired together. This method is easy, saves time, and to an extent…works great. However, there are several advantages to coping vs simply mitering.

  • Coping your inside corners will help compensate for material expansion and contraction. It also allows for some variation in the angle of the wall.
  • The ability to cope either piece around the other allows you to consider the angle of the viewer. By coping the correct piece you are able to limit the ability to look squarely at the joint. Our depth perception will not even notice a 1/16” separation. Whereas a “head on” view of a joint will easily show the separation as well as a telltale shadow. Always consider ways to decrease exposure and hide the joint as much as possible.

Running your first pieces:

Area1

Coping Pieces

You can begin by running your straight pieces, even those these are “straight” I like to use a 2-degree miter to each end to compensate for any unevenness in the corner. It is with these straight pieces your coped pieces will join. On this project my straight pieces will be the 2 opposite short walls of the sink and toilet.
Note: The most common viewing positions in this room will be from either long end of the room, facing the other end. By running the two opposite short walls as my straight pieces, I have decreased the “exposure” of the actual joints.

Making Cuts:

Mitering Trim

This is where you’d expect things to get really complicated… so take a deep breath, remember the 60 min IPA will be waiting, and stay with me!

Whenever possible you will want to cut the piece in the same orientation that it will lay attached to the wall. This practice is the easiest way to ensure your miters will be at the correct angle.

Using your miter saw, holding your piece in the correct orientation, make a 45-degree cut (as pictured above). This will leave you with a very clear line to cut with your coping saw.

Making the Copes:

Coping1

To make a coped joint in a corner (90-degrees) you will be joining a straight piece (that is already in place) with one that you will be coping, like a puzzle piece. When slid together the two will fit perfectly, even if the corner is not a perfect 90-degrees.

Using your coping saw follow the “line” you just created in the profile of molding that was created by the 45-degree cut. Be sure to hold your coping saw at a 3+ degree back bevel so the profile of your molding comes to a slight point. (allows for a tight fit).

Coping Trim

Sanding Coped Cut

Once your cut is finished you may want to “tune it up” using a piece of 120 grit sandpaper to make any final tweaks to your joint. You can use a scrap piece of the same molding to check and make sure it fits tightly.

Be careful not to round the front edge of the cope. A rounded edge will cause a shadow and the appearance of an ill fit!

Cutting To Length:

Marking in Place

Marking in Place

Next you will need to cut the piece to the correct length. The ideal way to do this is to bring the piece to your installation area, dry fit the piece, and mark your measurement.

This also allows you to check your coped joint before you make the final cut to length. Often, I will used a 2-degree bevel to allow my baseboard to meet my door casing as tightly as possible.

If you are working in a confined space, or where you have to make coped cuts on both ends of a piece (advanced technique) you will need to be able to use your measuring tape to help you figure out the length of your finished piece. To increase the accuracy of your measurement when you transfer it on to your work piece, you can use the “burn 1” technique as illustrated below.

Burning an Inch:

Measuring: Burn an Inch

Often, a bent or jammed tape measure hook can leave you with a piece that is just barely too short. If you want to get the most accurate measurement out of your tape, try “burning an inch.”

Instead of hooking your tape on the piece to pull a measurement you hold the one inch mark on your cope cut line, and in return add 1” to your overall measurement to compensate for the inch you are loosing when you burn 1”.

Finished product:

Finished Base and Chair Rail

You’ll use the same techniques on the chair rail as on your baseboard.  All outside corners should be glued. 18ga brads are great for keeping those miters tight while the glue dries.

With any luck the only thing you’ll need filler or caulking for would be the nail holes and top of the baseboard where it meets the wall.

All pieces should be secured with 1 ¼-1 ½ inch finish nails (larger nails may be needed depending on profile of moldings and thickness of wallboard…but we’ll tackle fastener length another time.)

Now it’s time for that IPA!

-Nick Michaud

 

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