What it is called, by market
One concept, four markets. Where a name means something else locally, the card says so rather than leaving you to find out on site.
United Kingdom
Close, not identicaldado rail
also chair rail, dado, waist moulding
Named from the dado — in classical architecture the lower part of a wall treated as the pedestal of a column — so the rail marks the TOP of that zone rather than the back of a chair.
Australia
Same word, different thingdado rail
also chair rail, picture rail
Picture rail is a different moulding entirely, set much higher near the cornice and designed to hang pictures from. The two get conflated in conversation and never in a specification.
United Statesyours
Close, not identicalchair rail
also dado cap, chair molding
Named for the furniture it protects the wall from, which implies a height set by a chair back — typically lower than the classical dado line, and the reason the same room reads differently under the two conventions.
Canada
Close, not identicalchair rail
also dado rail, chair molding
As the United States, with dado rail understood and used more often than south of the border.
The governing standard, by market
United Kingdom
BS 1186-3
Timber for joinery: workmanship, including the fit of mouldings and the tolerance on their joints.
United States
WM series / WDMA I.S.4
Standard moulding profile numbers and the specification of wood mouldings.
Calculators for this
Each works in either measurement system, and the terminology on the page follows whichever market you have selected.
Frequently asked questions
- How high should it go, and why do the two names disagree?
- Because they descend from two different ideas of the thing. The classical DADO is the pedestal zone of a wall, and its proportions come from the order the room is imitating — which puts the rail somewhere around a fifth to a quarter of the wall height, so it rises in a tall room and drops in a low one. The American CHAIR RAIL is named for what it protects the plaster from, which fixes it at the height of a chair back regardless of the ceiling. In a standard modern room the two land close enough that nobody notices; in a tall Victorian room they are far apart, and a chair-rail height in a four-metre room reads as a mistake because the proportion is wrong even though the function is served. The practical rule is that the rail should relate to the openings in the room — ideally aligning with a window cill or a door rail — rather than to a number.
- Is a picture rail the same thing higher up?
- No, it is a different component with a working job. A picture rail is a moulding set near the top of the wall, usually just below the cornice, with a lipped profile shaped to take a hook — so pictures hang from cords rather than from nails driven into the plaster. That was the point of it: in a lath-and-plaster room, hanging from the rail avoids making holes in a surface that does not take them well, and it lets a picture be moved without repair. A dado rail has no such profile and will not hold a hook. Both are horizontal mouldings on a wall, and confusing them on an order produces a length of the wrong section that cannot do either job.
- How much does a room actually take, and why is it more than the perimeter?
- The run is the perimeter of the room minus the door openings, plus the length lost to mitres and plus what is spoiled in cutting. Two things push it past the obvious figure. Every external corner is mitred, and the long edge of a mitred piece is longer than the wall it covers by the depth of the moulding at each end — so a bay window with five short returns loses noticeably more than a plain wall of the same length. And the stock length is what actually governs: mouldings come in fixed lengths, and a wall a little longer than one stock length needs two, leaving an offcut usually too short to be the next wall. Ordering the bare perimeter plus a flat percentage tends to come up short in rooms with many corners and over-order in plain ones.