Description
Casing Flat Stock: Square Door Trim With Nothing to Argue About
Walk through almost any recently built or recently renovated home in Waterloo Region and the trim around the openings will most likely be plain and square. That is not laziness. Flat casing has become the default because it does its job without asking for attention, and this stock, 5/8 inch thick by 3-1/2 inches wide in 8 foot lengths, is the version most projects reach for.
Where the square look comes from
The unornamented board has a long pedigree. Craftsman and arts and crafts interiors built their whole trim vocabulary from flat boards of differing widths, stacked and layered so that proportion, not carving, carried the design. What reads today as contemporary minimalism is in large part craftsman trim logic, stripped back further and painted white.
That history is useful when you are matching a house rather than following a trend. Flat stock is at home in a century home with simple original mouldings, in a mid century bungalow and in a new build alike, because it never announces a period of its own.
Square corners and how they change the work
Most casing must be mitred at the corners, because a shaped profile only meets its neighbour convincingly at forty five degrees. Flat stock is the exception. Because the face is a single plane, square door trim can be butted square, with the head piece running across the top and the legs meeting it underneath in a simple butt joint.
That opens up the layered craftsman approach, where the head is cut wider than the legs or extended slightly past them to form a small projection. It also makes the trim more tolerant of a wall that has moved, since a butt joint does not open into a visible wedge the way a mitre does. Mitred corners remain perfectly correct on flat casing, and many installers still prefer them, so the choice is one of style rather than necessity.
Pairing with flat stock baseboard
A square casing belongs with a square base. Where flat stock baseboard runs into the side of this casing at floor level, the two flat faces meet cleanly and the joint needs no scribing or shaping, which is one of the reasons the pairing has become standard practice. Keeping the base taller than the casing is wide preserves the proportion that makes the combination look deliberate.
As with any casing, this trim covers the gap between the jamb and the drywall, with a reveal of about a quarter inch normally left along the jamb edge. On a flat profile that reveal is the only shadow line the trim has, which makes keeping it consistent all the way around the opening genuinely important. The moulding is primed and is normally painted after installation.
Fitting advice
We recommend professional installation. Plain trim hides nothing: an uneven reveal, a proud joint or a wall that leans will be plainly visible on a flat face, where a shaped profile might have disguised it. An installer will shim, scribe and set the reveal so the simplicity looks effortless rather than approximate. Confirm the profile, the material and the quantities you need with our team before ordering, and let us know whether you plan to butt or mitre the corners.
Simple profiles are surprisingly hard to judge from a photograph, since thickness and edge treatment are exactly what the camera flattens, so look closely at the product image and come and see a length in daylight if you can. Casing Flat Stock is available for pickup in Kitchener and Cambridge, inventory on trim is limited, and shipping and financing are available. Bring your measurements to 107 Manitou Drive, Unit 13, and we will help you settle quantities for the whole project.
