Measurements in,
cut list out.

One wall, two days, and only one of them is work. A 12-foot interior wall of board and batten is a morning of measuring and cutting, an afternoon of nailing, then filler and caulk before you stop. Day two is sanding the filler and two coats of paint. What goes wrong is rushing the caulk. It needs to skin over before paint or it drags and you see every bead. If you are working the layout out on the wall as you go, add half a day and expect to waste a few pieces.

Primed MDF for anything that gets painted and stays dry. It is flat, it has no grain to telegraph through paint, and it is the cheapest of the three. Poplar if the wall is in a hallway or beside a door where it takes knocks — MDF dents and the dent stays. Pine only if you are staining, and even then knots bleed through paint no matter how many coats go on, so it wants a shellac-based primer first. Do not use MDF in a bathroom or a basement that has ever been damp. It swells at the bottom edge and never comes back.

A miter saw, a brad nailer, a 4-foot level, a tape, a caulk gun and a stud finder. That is the whole list. You can rent the saw and the nailer for a day for less than the wood costs. A hand saw and a miter box works and it is slower than people think. A wall with twenty battens is forty cuts. A laser level saves more time than anything else you can add, because it puts your rail line on the wall in one shot instead of walking a level across it.

Width and height in inches, to the sixteenth. Measure the width at the top, the middle and the bottom, and use the smallest one. Walls are not square, and the number that matters is the one your top rail has to fit into. Height is floor to ceiling at both ends. If there is a window in the wall, measure from the left edge of the wall to the left edge of the opening, plus the opening's own width and height. Everything after that is layout, and layout is arithmetic nobody should be doing on a phone at nine at night.

Three ways to do it and they are not the same job. Leave it and land the battens on top of it — fastest, and the battens sit proud of the baseboard by whatever the baseboard is thick, which reads unfinished unless the battens are thicker. Take it off and reinstall it over the bottom rail — the cleanest look, and the reason most finished walls you have seen look the way they do. Or run a flat bottom rail and no baseboard at all, which is the modern read and the easiest to paint. Pick before you cut. The batten length changes with the answer.

In the gaps, never on a batten. An outlet under a batten means cutting the batten around the box, adding an extension ring, and a plate sitting half on wood and half on drywall. Move the layout instead. Shift the field an inch or two and let the spacing absorb it. This is the most common reason a wall that looked right on paper looks wrong on the wall, and it is also why a pre-cut kit cannot help you. A kit assumes a clean rectangle.

No. Trim this light holds on construction adhesive and 18-gauge brad nails into drywall. Studs are worth finding for the top rail if you are putting a shelf ledge on it, and for nothing else. What matters more is nailing at an angle. Two brads toed in opposite directions hold better than four driven straight.

One gallon covers a normal accent wall with two coats, battens and all, with paint left over. The battens add surface but almost no square footage. A 12 by 8 wall is 96 square feet and twenty battens add maybe 25 more. Buy the gallon, not two quarts. Spray it if you own a sprayer; a 4-inch roller with a brush for the edges gets the same result in about three times the time.

Between $80 and $200 for a normal wall, depending on what you build it from and how tall it is. Primed MDF at the low end, poplar at the high end. Add a tube of adhesive, a tube of paintable caulk, a tub of filler and a gallon of paint. What people underestimate is not the wood. It is the second trip to the store, and the second trip happens because the cut list was wrong.