1
100 mm sphere rule
A test for guarding in buildings children under five may use: a 100 mm sphere must not be able to pass through any opening, to avoid children being trapped.
Also called: sphere test, 4 inch gap rule
2
2R + G rule
A comfort rule of thumb for stairs: twice the rise plus the going should come to between 550 mm and 700 mm. ADK refers to it as the normal relationship.
Also called: twice the rise plus the going
3
32 mm system
A cabinet-making convention of drilling rows of small holes at 32 mm spacing so shelves, hinges and runners can be fixed at standard positions.
Also called: system drilling, Euro drilling
A
Architrave
The moulded trim that frames the opening around a door or window and covers the gap between the lining and the wall finish.
Also called: casing (US), door trim, window casing
Astragal
A small half-round moulding. Sources disagree on whether it is a small torus, a bead, or the strip that covers the gap between a pair of doors, so always draw it.
Also called: bead (small), baguette (very small)
B
Balancer
A veneer or sheet on the back of a panel with similar properties to the face, applied to stop the panel bowing as humidity changes.
Also called: backer veneer, balancing veneer, counter-veneer
Baluster
A vertical bar or post between a stair's handrail and its base rail or string, forming the infill that stops people falling through.
Also called: spindle, banister (loose)
Balustrade
The complete barrier of handrail, posts and infill at the open side of a stair, landing or balcony.
Also called: balustrading, guarding
Bead
A narrow half-round moulding, often used as an edge detail or to hide a joint; several together make reeding.
Also called: beading, reed (multiple beads)
Bolection
A raised moulding that stands proud of the surrounding frame and overlaps the joint between a frame and an inset panel.
Also called: bolection moulding
Bullnose
A rounded top front edge on skirting or trim; simpler than an ogee or torus and common in modern schemes.
Also called: pencil round, round edge
Butt hinge
A traditional hinge with two flat leaves joined by a pin, fitted into rebates on the door edge and frame.
Also called: leaf hinge
C
Carcase
The basic box of a cabinet, made of sides, top, bottom and back, before doors, drawers and shelves are added.
Also called: carcass, cabinet box
Cavetto
A concave moulding about a quarter of a circle, the hollow counterpart of the ovolo.
Also called: cove (concave quarter round)
Centre-to-centre
The distance between the centres of a handle's fixing holes, which is how handles are sized; the handle's overall length is longer.
Also called: c/c, c-c, hole centres
Chain of custody
The documented trail that follows certified timber from forest to finished product so a 'certified' claim can be passed on. It must be maintained by each business in the chain, including the maker.
Also called: CoC, FSC claim, PEFC claim
Chamfer
A flat angled cut that removes the sharp corner of a piece; a stop chamfer ends part way along so the original square section remains at the ends.
Also called: bevel, stop chamfer (stopped before the end)
Concealed hinge
A cabinet door hinge that sits in a round hole bored in the back of the door and cannot be seen when closed, with adjustment in three directions.
Also called: cup hinge, Euro hinge, 35 mm hinge
Cornice
A projecting moulding at the top of a wall where it meets the ceiling, which can be plaster, timber or other material. In classical terms, the uppermost part of an entablature.
Also called: crown moulding (US), crown molding
Coving
A simple concave moulding at the wall and ceiling junction, usually plain rather than stepped, in plaster, plasterboard or polystyrene.
Also called: cove moulding
Cyma reversa
An S-shaped double curve with the convex part above the concave part, which is the form most people mean when they say ogee in joinery.
Also called: ogee (loose), reverse ogee, cyma recta (the opposite S-curve)
D
Dado rail
A horizontal moulding fixed part way up a wall, traditionally to protect the plaster from chair backs and to mark the top of the lower wall treatment.
Also called: chair rail (US), chair moulding
Declaration of Performance
The manufacturer's statement of a construction product's declared performance (for example its Euroclass), which accompanies CE or UKCA marked boards.
Also called: DoP
Doorset
A door leaf supplied or certified together with its frame, seals and ironmongery as one tested unit.
Also called: door set, door assembly
E
Edge banding
A thin strip of veneer, PVC or ABS applied to the raw edge of a board and trimmed flush.
Also called: edge tape, ABS edge
Effective clear width
The usable width through an open door, measured at right angles to the wall from the door stop on the closing side to the nearest obstruction on the hinge side.
Also called: clear opening width, ECW
Euroclass
The European system for rating how a building product reacts to fire, from A1 (non-combustible) to F, with extra letters for smoke (s1 to s3) and flaming droplets (d0 to d2).
Also called: reaction to fire class, BS EN 13501-1 class
F
FD30S
A fire door that withstands fire for 30 minutes (integrity) when tested to BS 476-22; the S suffix means it also limits smoke leakage at room temperature. In the European system the equivalent notation is E30 with an Sa classification.
Also called: FD30, E30 Sa, EI30
Fielded panel
A panel whose centre is raised above its edges, with the raised area (the field) surrounded by a bevelled or shaped border that fits into the frame.
Also called: raised and fielded panel, raised panel
Fire resistance
How long a whole element, such as a door or wall, keeps flames, hot gases and heat from passing through, measured in minutes.
Also called: integrity, insulation (EI)
Fluting
A pattern of parallel concave grooves cut into a surface, originally on classical columns and now common on panels, doors and furniture fronts.
Also called: fluted panel
FR MDF
MDF treated for improved reaction to fire, often tested to a Euroclass B or C, supplied with a Declaration of Performance.
Also called: fire-retardant MDF
G
Going
The horizontal distance from the front edge of one tread to the front edge of the next, which is not the same as the width of the tread board.
Also called: tread depth (loosely), unit going
H
Handrail
The rail you grip as you climb a stair. ADK sets its top at 900 to 1000 mm above the pitch line or floor.
Also called: banister (loosely)
Hanging rail
The tube or bar on which clothes hang in a wardrobe, with its support spacing and finish being the main specification choices.
Also called: wardrobe rail, clothes rail
Hardwax oil
A finish of natural oils and waxes that soaks into timber, leaving a low-sheen, repairable surface instead of a hard film.
Also called: hard wax oil
I
Intumescent seal
A strip fitted in the door or frame that swells when heated to close the gap around a fire door. BWF's position is that it should be fitted on every fire door.
Also called: intumescent strip, fire seal
J
Janka hardness
A measure of how hard a timber is, based on the force needed to push a standard steel ball half its width into the wood; it indicates denting resistance, not stability or durability.
Also called: Janka rating
Jib door
A door finished flush with the wall surface and without architraves, often panelled or papered to disappear into the wall.
Also called: hidden door, concealed door, secret door
L
Lipping
A thin strip of solid timber glued to the edge of a board to protect it, hide the core or give a solid look.
Also called: solid edge, edge lipping
M
Manifestation
Markings or other visual features on large areas of clear glazing so that people notice it. ADK asks for marking at two heights, using a logo at least 150 mm high or bands at least 50 mm high.
Also called: glass door marking
MDF
A board made from wood fibres bonded with resin under heat and pressure, giving a smooth, even surface that takes paint well.
Also called: medium density fibreboard
MDF.H
The EN 622-5 type of MDF made for humid interior conditions, usually sold as moisture-resistant (MR). It is not suitable for outdoors.
Also called: MR MDF, moisture-resistant MDF
Moisture content
The weight of water in a piece of timber as a percentage of its oven-dry weight; joinery should be near the humidity it will live in to avoid movement.
Also called: MC, timber moisture
Moulding
A shaped strip of timber, plaster or other material used to decorate or finish a junction or edge, defined by the cross-section (profile) cut into it.
Also called: molding (US), trim, millwork (US)
N
Natural durability
A timber's built-in resistance to decay fungi and insects, graded from very durable to not durable in BS EN 350.
Also called: durability class, BS EN 350 class
Newel
The main upright post at the foot, top or turn of a stair that carries the handrail and often the string.
Also called: newel post
Nominal size
The size a piece of timber is sold as before planing, which is larger than the finished size. A '25 x 75' board may finish nearer 20 x 70 mm.
Also called: sawn size
Nosing
The rounded or projecting front edge of a stair tread or similar step; also used for the rounded front edge of a shelf or counter.
Also called: stair nosing, bullnose step
O
Ogee
In joinery usage, a double-curved S-shaped profile; in strict classical terms it can mean either of the two cyma forms, so a drawing is safer than the word.
Also called: OG profile
Overlay
How a door sits relative to its carcase: overlay doors cover the front edge, inset doors sit flush inside the opening. The hinge type depends on which you choose.
Also called: inset, full overlay, half overlay
Ovolo
A convex moulding shaped like roughly a quarter of a circle or ellipse, often used on panel edges and the sides of a cornice.
Also called: quarter round (convex)
P
Picture rail
A horizontal moulding fixed high on the wall, usually near the cornice, from which pictures are hung on hooks so the plaster is not drilled.
Also called: picture moulding
Pitch
The angle of a stair measured from the horizontal; the pitch line is an imaginary line joining the nosings of the treads. For a private stair the maximum pitch is 42 degrees.
Also called: pitch line, angle of stair
Pivot door
A door hung from pivots at the top and bottom, set in from the edge, instead of side hinges, which allows very large leaves.
Also called: pivoting door
Plinth
The recessed base under a run of cabinets or a wardrobe, which gives toe space and lets the floor be scribed against it.
Also called: kick board, toe kick (US)
Plinth block
A square block at the foot of a door architrave that takes the skirting so the two do not have to meet at a mitre; a corner block does the same at the top corners.
Also called: corner block, architrave block, bullseye block
Pocket door
A door that slides on a track into a hollow within the wall rather than swinging, saving swing space but needing a deeper wall build-up.
Also called: sliding pocket door, cavity slider
Profile
The shape you would see if the moulding were sawn across its length. Two mouldings with the same name can have different profiles, so a drawing beats a name.
Also called: section, moulding section
Q
Quarter sawn
Timber cut so the growth rings run roughly at right angles to the face, which gives straighter grain, better stability and ray figure in oak.
Also called: quartersawn, rift (related)
Quirk
A small V or U shaped groove next to a bead or edge that separates it from the face and gives a crisp shadow line.
Also called: quirk bead
R
Rail and stile
The framing of a panel: stiles are the vertical members and rails the horizontal ones, with the panel set into grooves between them.
Also called: frame and panel, stile and rail
Reeding
A decorative pattern of parallel convex ridges, the opposite of fluting. Reeded panels are sold in timber and veneered boards.
Also called: reeded panel
Rift sawn
Timber cut with the rings at about 30 to 60 degrees to the face, giving a straight, even grain without the ray flecks of quarter-sawn oak.
Also called: rift cut
Rise
The vertical height from the top of one step to the top of the next.
Also called: riser height, unit rise
Running match
A veneer layout term whose meaning differs between sources: some use it for leaves laid in sequence without regard to appearance, others as a separate method from balance match. A specification should define it rather than use the word.
Also called: random match (contested)
Rw
A single-number rating of how much airborne sound a door, wall or window blocks in a laboratory test, in decibels; higher means better.
Also called: weighted sound reduction index, Rw dB
S
Safety glazing
Glass that meets the impact class required by building regulations where people might fall against it, such as in doors, side panels and low windows. Class 3 of BS EN 12600 (or Class C of BS 6206) is the general criterion.
Also called: critical location glazing
Scotia
A deep concave moulding made of two arcs of different radius, so it looks hollowed out and throws a strong shadow.
Also called: cove (loosely)
Scribe
To shape the edge of a panel or board so it follows an uneven wall, floor or ceiling; a scribe strip is a deliberately oversized piece cut to fit.
Also called: scribing, scribe strip
Shadow gap
A deliberate recessed gap, usually 6-12 mm, at a junction such as skirting to wall, that hides the irregularities of the wall and reads as a clean dark line.
Also called: reveal, reveal bead, shadow line
Shaker panel
A plain flat panel set within a square-edged frame without raised fields or mouldings.
Also called: Shaker style, recessed panel
Sheen
How shiny a finish is, measured in gloss units at 60 degrees; matt is low, high gloss is high. The same colour looks different at different sheens.
Also called: gloss level, gloss units (GU)
Skirting board
The board fixed along the bottom of a wall where it meets the floor, covering the junction and protecting the wall from knocks and cleaning.
Also called: skirting, baseboard (US), base moulding (US)
String
The sloping board along the side of a stair that supports or houses the treads and risers; a closed string covers them, an open string is cut to show them.
Also called: stringer, stair carriage
T
Through-and-through
A way of cutting a log by sawing straight through it into parallel boards, giving a mix of plain-sawn and quarter-sawn grain.
Also called: live sawn, slab sawn
Torus
A bold convex rounded moulding, often a half-round or near half-round, used at the base of columns and as a skirting profile.
Also called: tore
Two-pack lacquer
A hard-wearing lacquer that cures through a chemical reaction after a hardener is mixed in; widely used on furniture and joinery.
Also called: 2K polyurethane, 2K PU, catalysed lacquer
W
Wall lining
In Approved Document B, the surface of walls and ceilings, which must meet a reaction-to-fire class; the definition expressly excludes doors and frames, architraves, cover moulds, picture rails, skirtings, fireplace surrounds, mantle shelves and fitted furniture.
Also called: lining (ADB sense)