Simple Shadow Box Detail
Make an ordinary room look extraordinary just by adding some basic trim molding under new or existing chair rail.
One of the great things about finish carpentry is that you can make an ordinary room look extraordinary just by adding some basic trim molding. Adding simple shadow boxing under new or existing chair rail is an easy way to dress up a room. Shadow boxing is generally made up of 1 1/4 in. base cap molding “picture framed” to create a box on the wall. For the proper look, the base cap should be installed with the “chunky” side on the outside edges of each box. I use 2 assumptions when laying a room out: 1.) The average box size will be somewhere around 30 in – 40 in. 2.) The space between boxes will be around 4 in. This size and spacing gives a nice balanced feel within the room. However any size box, molding, and spacing is acceptable as it’s based on preference.
My process for laying out the boxes to feel balanced is fairly simple. I think of a room in wall sections, or any flat wall space that runs horizontally until a vertical break (corner, window, door, etc). Upon entering the room I look for a wall section that will allow for only 2 boxes based on the 30 in. to 40 in. average size. I then find the center point of this wall section (in inches) by measuring the length and dividing by 2. This gives me a rough average box size for the room, call it “S” (hello Algebra!) “S” is key to determining how many boxes go on each wall section. All measurements should be in inches to prevent the extra step of converting foot to inches.
Next measure any wall section longer than the initial wall used to find the rough box size and divide it by “S”. This will determine how many shadow boxes are needed on that particular wall section, or “B”. Since you will most likely never end up with a perfect whole number of boxes, a little extra figuring is in order. Start by rounding UP to the nearest whole number of boxes needed. Take your total wall section measurement and divide by the number of boxes. This will give you “X”, which should be somewhere close to the rough box size (“S”) determined from above. Now, repeat the process by rounding DOWN. Whichever “X” number is closest to “S,” is what I go with.
Now, mark the wall section in equal lengths using “X.” These marks represent the center line between each shadow box. Assuming the space between each box to be 4 in, draw a vertical (or plumb) line 2 inches to the right and 2 inches to the left of each center line. These are the outside vertical edges of each shadow box.
I use this process for all wall sections that are longer than the original wall section used to find “S”. (Any wall section smaller, gets one box.) After all of the vertical lines are laid off, I cut a scribe block that measures 1/2 of the spacing between boxes – in this case 2 inches. I then scribe all perimeters of each wall section.
Now that all of the lines are marked, measure the base cap molding pieces using the box dimensions you have drawn on the wall. I apply a bead of paintable adhesive caulk to the back side of the molding pieces, paired with 1 1/4 inch – 18 gauge brad nails to secure them to the wall. You can attach each piece individually or pre assemble each box before mounting it to the wall.
TIP: Often times electrical outlets have not been laid off in anticipation of shadow boxing. This can be a problem if the molding is to intersect with an outlet. The easiest way to avoid this is to adjust the size of the space between boxes to shift them slightly one way or another. When that option doesn’t work, I build a small box out of 3/4 inch material around the outlet. This provides a stop for the molding to die off into.
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