Chair rail, wainscoting, and shadow boxes, also called picture frame boxes, are simple woodworking projects the do-it-yourselfer can accomplish with common hand and power tools. They can improve the value and look of your interior spaces especially foyers, dining rooms, living rooms, and staircases.
Shadow boxes are a common architectural feature that is produced by applying rectangles or parallelograms of small trim over painted walls. This gives the appearance of wainscoting without adding layers plywood or medium density fiberboard or MDF for short. In almost all cases, there is some sort of chair rail or trim to create the appearance of solid wainscot and also for aesthetics. The chair rail is usually set at a height between 32 and 36 inches, but I will talk more about that later.
The most common moldings used for shadow boxes are either base cap or panel moldings. Some of these moldings have a lip on the bottom edge which is used to cover or overlap the paneling or baseboard they are applied over. There are various styles of both types of molding, so it is best to look at what’s available at lumber yards or home centers. Simple is usually better. Typically the boxes are constructed as a single unit then attached to the wall with nails and construction adhesive. The flat, thicker edge is used for the outside of the shadow box. Use standard miters for all joints. When installing along a staircase wall, you will need to measure the angles,; it’s best to layout the shape of the parallelograms in pencil on the wall to make sure you have correct lengths and angles.
The most important step in installing shadow boxes is determining the number and spacing of the boxes. Measurements are taken from corner to corner on blank walls, or corner to any openings, or between openings. Once this measurement is found, you should allow 4 to 6 inches on each end of the wall, and slightly less between panels in the wall, 3 inches is usually a good number, but this will vary slightly from wall to wall.
It is likely that no two walls will be the same in the room, so you need to try to keep the panels fairly close in size. The height of the boxes will all be the same, but the widths will vary slightly. All the boxes should be the same size in a wall section, but the ends can be smaller if this helps make them match other walls in the room. Be mindful of the location of outlet covers and try to adjust your design to miss them. They can be placed inside or outside the boxes.
For a wall 14 feet long, come in off each corner 6 inches. This will leave 13 feet of shadow box space.
Set the width of the shadow boxes at 16 inches, divide 156 inches (13 feet multiplied by 12 inches/foot = 156 inches) to get 9.75.
Since you will more than one inch between boxes, (0.75 feet equals 9 inches) go down to 8 boxes. Multiply 8 by 16 inches to get 128 inches. Subtract this from the original 156 inches of shadow box space to get 28 inches left to divide between the boxes.
Now it gets a little tricky so it’s best to draw a little sketch to keep track of what is going on. You don’t need any space on either end because you allowed 6 inches in the beginning, so the 28 inches is divided by the 7 spaces in between the boxes. This gives you 4 inches between boxes. Not too bad.
For rooms that are not built to the exact foot, adjust your end distance to make the math easier. The distance from the top of the baseboard and the bottom of the chair rail should also be equal and this will determine the height of the shadow boxes.
When going under windows, try to maintain the distance used from the top of the baseboard and bottom of the rail. It will look fine, this is how it was done in the old days.
Building the Shadow Boxes
As stated earlier, it is best to construct the boxes before hand and then attach them to the wall with finish nails and construction adhesive. The reason for this is that in most cases you will not hit a stud on the sides of the boxes, so don’t even try.
When building the boxes, nail the corners together using 4 penny finish nails and carpenter’s glue on the miter cuts. Set and fill the nails with wood filler or painter’s putty. It is also a good idea to paint the boxes the finish color or at least prime them. This will save a lot of time, especially if you plan on painting the boxes a different color than the wall. This will mean all you have to do is touch up where you named them into the studs.
Use a stud finder or tap the wall to locate the studs. Apply a thin bead of adhesive to the back of the shadow box and nail where you can using 6 or 8 penny finish nails. Set and fill the nails. You can also tack the box into the drywall to keep it tight to the surface until the adhesive dries. Be careful when working around receptacles and walls where you think there are pipes.
To determine the height of the chair rail, measure the height of the ceiling and divide it by three. The general rule is that the chair rail should be about 1/3 of the way up from the floor, usually between 32 and 36 inches for an 8 foot ceiling. You can also slide a chair up to the wall and mark where it would hit the wall. Once you've determined the height, use your tape measure and level to make a level line along the whole length of the room. Floors are not always level, so using a level to set your line will ensure that your chair rail will be straight. You should also flip your level over after drawing a line so that it will even out if your level is slightly off. Even if a 4-foot level is out 1/32 of an inch, your line will be 3/8 of an inch higher or lower if you work your way around a 12’ by 12’ room. (It would take 12 lengths of a 4-foot level to mark the perimeter of a 12 by 12 room; 12 times 1/32” equals 3/8”)
Use the techniques stated in my Factoid “How to Install Wood Trim for the Do-It-Yourselfer” https://knoji.com/installing-wood-trim-for-the-do-it-yourselfer-tips-and-techniques/
Coping the miters of the inside corners works best for installing chair rail. You can also install a built-up chair rail by installing a flat double-edged molding as a base and then another chair rail on top of that. Do some research in woodworking magazines or online to find out what you think looks best.
Wainscoting can be ornate or simple, but the installation process is the same. Apply the layer of paneling on the wall first. This can be flat MDF, bead board, or raised panels. For the bead board or MDF, install 1 by 4 pine or ¾ inch MDF cut to width over the seams of the panels. Use the technique described in the shadow box layout to determine where the stiles, vertical pieces, will be placed. The rails, the top and bottom pieces, go the length of the room. You will need to remove the baseboard and install the lower rail in place of the baseboard. This is because the panel will stick out past the edge of the baseboard as well as the ¾ inch thick rail. Use cove molding or quarter-round to cover the inside edge of the rails and stiles. You will need a different type of cap, usually a small paneling cap or sill with a rounded front is nailed on the top of the top rail. A piece of molding is installed below the cap, such as solid crown or other similar profile. The top of the wainscot will be the same height as that of a chair rail.
Cherry Wainscot Raised Panels
Hopefully this article will answer some questions on how to install so great looking woodwork for your home.