Mitered Baseboard Install: Cutting 44° and 46° Corners in a Rental

Installing baseboard in a rental room, a Vancouver carpenter works with primed pine 1×4, three quarter inch by three and a half inch. Flat stock like this he would usually cut square and butt into the corners, but here he miters the inside corners to show different information. Outside corners are mitered either way.

Checking the corners

Before measuring, he cuts a couple of spare pieces at 45 degrees and holds them in the corners to judge how square each one is. One corner is badly out of square, yet a 45 turned out not to be that bad there. He often cuts inside corners at 44 degrees and outside corners at 46. On an inside corner the tape and mud are built up, and on an outside corner the wall is built out, so the angles differ from 90 degrees in opposite directions.

Measuring and cutting

He measures from the inside corner, noting that mitered inside corners are a little easier to measure and mark. He warns to check the tape is not butting into a coved or built-up bottom corner, since tape and mud can build up about an inch above the floor. He checks the primed pine for paint flaws and uses the nicer side. The longest point of a cut is at the top, so he makes sure the board reaches it. To fine-tune a cut he holds the board against the fence and slides it a tiny amount by hand. He adds a small chamfer to the end of the board, marks the saw for it so every cut matches, and notes that it stops an ugly butt end. He says the saw blade needs replacing, and that cutting from the other side risks blowout. He also says moving trim around a finished room is why trim carpenters ding walls.

Gluing and nailing

He pushes the piece down before nailing and finds studs by trial, nailing into the bottom plate where he knows there is wood. Glue goes on the miters, sometimes spread over the whole face to avoid a starved joint, with a wet cloth at his belt. He says Weld Bond dries clear. He does not nail the corners first, since they can still be adjusted, and leaves good-looking joints un-nailed because nails can pull a corner in and open it. He reminds viewers that brad nails hitting a nail can spike out, and that it is good to know what is behind the wall, such as pipes.

Problem spots

Where a corner was not square he trimmed the back of a piece and used an angle grinder with a flap disc to notch one end. Where there may be nothing to nail to, he uses carpenter's helper filler, and caulking as an adhesive instead of PL because it wipes clean. He says installers on steel stud used caulking since brad nails only grab temporarily. An overhanging miter is sanded while the glue is wet, so the dust turns into filler. A final outside corner opened up, so he glued it, worked in sawdust and nailed the joint, expecting a couple of coats of paint to hide it.