How To Build A Wood Beam Ceiling

In most cases, the beams will run across the shortest dimension of the room to mimic exposed joists above, although they can run the other way, or they can run in both directions to create a boxed look. Usually, decorative beams are spaced fairly widely, say three or more feet apart. The width and depth of decorative beams should be proportional to the size of the room. The bigger the room and the higher the ceiling, the wider and deeper the beams. In rooms with 8 or 9-foot ceilings, beams that are about 5 inches wide and 3 inches or so deep are typical.

Get Started with Nailers

Once you have a layout you like, the first step is to attach a dimension lumber nailer at each beam location. Choose straight “2x” lumber for this. If you use 2x4 nailers, the width, plus two sides of ¾ inch finish material adds up to 5 inches. If you want wider beams, choose wider nailers. If you plan to have a frieze, that is, a board that runs along the wall at the ceiling intersection, end the nailers far enough away from the wall so you’ll be able to slip the frieze into place. If your beams will run the short dimension of the room, odds are that’s the same direction as the ceiling joists run. Let the layout of the ceiling joists dictate the layout of your beams.

Install the Sides and Bottoms of the Beams

The sides of ceiling beams are usually made from 1x3, 1x4, or 1x6 depending on the depth you want. You can use primed lumber or hardwood. If using hardwood, stain and finish it before installation. If the beam is to be painted, apply one finish coat before installation. The bottom material can be solid wood or plywood since the sides will hide the edges. You can make the bottoms of the beams two ways. Some people like to have the sides hang down, leaving a ¼ inch or so reveal below the bottom, while others want the bottom and the sides flush. Hanging down is a little easier, but it all comes down to preference. The simplest approach is to make the bottom of 1-by of the same width as the nailer; i.e. with a 2x4 nailer, use a 1x4 bottom.

If you want the sides to hang below the bottom, cut furring strips to attach to the bottom of the nailer. Say you are using 1x4 sides, a 1x4 bottom, and you want a ¼ inch reveal. The combined depth of the nailer (1 ½ inches), bottom piece (3/4 inch), and reveal (1/4 inch) equals 2 ½ inches. The 1x4 measures 3 ½ inches, so the furring will need to be 1 inch thick. Make sure the strips are narrower than the nailer by a ¼ inch or so and nail them to the 2-by nailer on the ceiling. Install the frieze if there is one, then cut the sides and bottom to length. Fasten one side to the nailer with 2-inch finish nails. Spread wood glue on one edge of the bottom, and with a helper to hold it in place, nail it to the installed side, again with 2-inch finish nails. If the bottom of the beam is to be flush, make sure you nail as close to that as you can. Once the glue dries, you’ll need to clean up any discrepancies with a sander. If there’s to be a reveal, hold the bottom tight to the furring on the nailer, but don’t nail it there until after you’ve nailed the sides to the bottom. Spread glue on the other edge of the bottom, hold the other side in place, and nail it to the bottom as well. You might need to clamp it here and there to get a tight joint. Wipe off any glue before it dries.

If you have access to a tablesaw, a better detail is to rabbet or dado the bottom edges of the sides so that the bottom piece fits into them. If the grooves are each ¼ inch deep, your bottom piece would have to be ½ inch wider than the nailer on the ceiling. If you want the sides of the beam to hang below the bottom, you can cut ¼ inch wide dadoes and make the bottom from ¼ inch plywood.

Add Trim Strips for a Final Touch

Most likely, the sides won’t meet the ceiling perfectly because ceilings are rarely perfectly flat. This gap gets hidden with a trim strip, which can be as simple as a piece of ¾ inch lattice or some cove molding. If the beams are really deep, you can even trim them out using a crown molding. No matter which approach you take, you will have created a fantastic ceiling that you’ll enjoy for years to come.