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
Same word, different thingarris
also arrised edge, eased edge, pencil round, chamfer, arris rail
Also a verb — to arris an edge is to ease it. And an ARRIS RAIL is the triangular-section rail in a close-boarded fence, which is a component and not an edge at all.
Australia
Close, not identicalarris
also arrised, pencil round, eased edge, arris rail
As the UK, and arris rail is equally standard in Australian fencing, so the component sense of the word travels alongside the edge sense.
United Statesyours
No local equivalentedge
also eased edge, chamfer, pencil edge, arris
Arris appears in stone and specification writing and rarely on site. The instruction is given as eased edge, pencil edge or chamfer — each of which names a specific profile rather than the general act.
Canada
No local equivalentedge
also eased edge, chamfer, bullnose
As the United States, with named profiles rather than a general term for easing.
The governing standard, by market
United Kingdom
BS 1186-3 / BS EN 1340
Workmanship in joinery including edge treatment, and concrete kerb units where the arris profile is part of the specification.
United States
ACI 117 / AWI Quality Standards
Tolerances for concrete construction including edge condition, and architectural woodwork edge profiles.
Calculators for this
Each works in either measurement system, and the terminology on the page follows whichever market you have selected.
Frequently asked questions
- Why ease an edge at all?
- Because a perfectly sharp edge is the weakest part of almost any material and the worst place for a coating. On CONCRETE and stone, a sharp arris is a thin wedge of material with no support behind it, so it spalls off at the first knock and takes a visible chip with it — which is why kerbs, steps and precast units are specified with a chamfer or a radius. On TIMBER, a sharp edge cannot hold paint: the film thins as it pulls away from the corner, so the coating fails at the arris first and lets water into the end grain behind it. That is the real reason joinery is arrised before priming, and it is why an edge sanded after painting has solved nothing. On METAL and glass it is a safety matter, and on tile it is what an edge profile exists to provide.
- What is the difference between arrising, chamfering and a bullnose?
- How much material comes off, and they are three specifications rather than three words. ARRISING or easing takes the sharpness off and nothing more — a pass with abrasive, leaving an edge that is no longer a blade but still reads as square. A PENCIL ROUND is a small consistent radius, roughly the radius of a pencil, and reads as a deliberately softened edge. A CHAMFER is a flat cut at an angle, usually 45 degrees, and reads as a bevel with two new arrises of its own. A BULLNOSE is a full half-round. Each looks different at a metre, each takes a different amount of time, and a drawing that says eased edge and gets a chamfer has received a visible design change.
- What is an arris rail, and why is it that shape?
- It is the horizontal rail in a close-boarded fence, and it is triangular in section — essentially a square section cut diagonally — with the flat face toward the boards and the apex toward the ground. The shape does two things. It sheds water: there is no upward-facing flat surface for rain to sit on, which is what rots a rectangular rail from the top. And it uses the material efficiently, giving depth where the bending happens while removing the material doing least work. It is one of the more elegant traditional sections, and it is why an arris rail is a stocked item in Britain and a fence rail is a plain rectangle almost everywhere else — different word, different shape, same job done less well.