The Traditional Height for Beadboard
If you have 8-foot standard ceilings in your home, Architectural Depot recommends cutting beadboard wainscoting into thirds and trimming off the extra five inches to a height of 27 inches. It suggests adding a top and bottom railing cap to the beadboard. A standard railing cap height is 6 inches, so the total height of the beadboard wainscoting and railing is 39 inches. Elite Trimworks recommends a similar total beadboard finished height of 38 inches.