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  1. Home
  2. /Stair glossary

Stair Glossary — Staircase terms from A to Z

Key staircase terms explained simply.

Note: Content currently available in German.

Topics in the stair glossary

The glossary is sorted alphabetically. To help you get started, we have grouped the most important entries by topic here.

Construction types

Construction types and their characteristics

  • Housed Stringer Stair (Classic Variant)
  • Saddled Stringer Stair
  • Folded-Plate Stair
  • Landing
  • Clad Stair
  • Concrete Stair

Woods and materials

Wood species, lamination, and surface options

  • Oak
  • Beech
  • Ash
  • Maple
  • Solid Wood Stair (Full Construction)
  • Glued Laminated Timber (Glulam Tread)

Geometry and dimensions

Going, rise, and tread components

  • Tread Depth (Going)
  • Tread Width — Historical Term
  • Projection Depth
  • Rise (Step Height)
  • Tread
  • Riser

Safety and standards

DIN, fall protection, and accessibility

  • Fall Protection
  • Balustrade
  • Accessibility
  • Accessible Stair
  • Building Approval
  • Building Codes and Regulations

Details and extras

Lighting, surface treatments, special forms

  • Stair Lighting
  • Staining
  • Bishop's Cap
  • Outdoor Stair

Planning and measurement

Preparation, measurement, and build phases

  • Site Measurement
  • Temporary Stair
  • Construction Protection
  • Comfort Rule
  • Levelling Stair
  • Folding Space

For in-depth overviews visit our main pages Stairs and Stair Treads.

A–Z · 231 terms

A

Accessibility

Staircase design without barriers for people with disabilities.

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Accessible Stair

Staircases meeting standards for people with disabilities.

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Alternating-Tread Stair

Staircase with alternately halved treads for minimal space.

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Ash

Hardest native wood — extremely durable and elastic.

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B

Baluster (Railing Spindle)

Vertical infill element between the handrail and the lower rail of a railing.

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Balustrade

Row of small columns as a classic, decorative railing form.

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Baroque Staircase

Representative stair form of the 17th and 18th centuries.

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Bearing Point

Points where stair loads are transferred into the building structure.

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Beech

Hard timber with uniform grain and warm colour tone.

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Bishop's Cap

Decorative edge trim on a staircase.

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Blind Stringer

Decorative stringer without primary load-bearing function.

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Block Step

Solid step made from a single piece of material.

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Bolt Stair (Structural-Bolt Staircase)

Apparently floating staircase with bolted treads.

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Bottom Newel Post

Lower railing post — also called the starting post — at the foot of the staircase; anchors the handrail at tread 1.

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Brinell Hardness

Standardised test method for determining wood hardness.

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Brushing

Mechanical surface texturing of wood for a rustic feel.

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Building Approval

Official approval for construction products and methods.

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Building Classes

Categorisation of buildings by height and area.

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Building Codes and Regulations

Legal regulations governing staircase construction.

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C

Cable Railing

Railing infill of horizontal bars or cables.

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CAD-CAM in Stair Construction

Integrated chain from digital stair design to CNC production.

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Cantilever Stair

Staircase with treads projecting freely from the wall.

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Ceiling Opening

Opening in the floor slab for the staircase passage.

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Centre-Stringer Stair

Staircase with a single central load-bearing beam.

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Cherry

Elegant timber with a warm, reddish-brown tone.

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Child Safety on Stairs (Overview)

Umbrella term for child-protective measures — gates, riser protection, railing spacing, safety strips.

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Clad Stair

Structural stair clad with finished treads of timber, stone or tiles.

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Clear Height

Free passage height above a staircase.

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Clear Step Gap

Vertical gap between a tread surface and the underside of the step above.

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Clearance Profile

Space to be kept clear above and beside the stair flight.

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Closed Stair

Staircase with risers between all treads.

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CNC Production in Stair Construction

Computer-controlled manufacturing of stair components on processing centres.

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Comfort Rule

Historical comfort formula for stairs: going minus rise equals 12 cm.

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Computer-Aided Stair Planning (CAD)

Digital stair design using specialised CAD software.

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Concrete Stair

Staircase made of reinforced concrete — precast or cast in situ.

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Construction Protection

Protective covering for staircases during the building phase.

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Corten Steel

Weathering steel with a characteristic rust patina.

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CPL Laminate

Abrasion-resistant laminate for stair surfaces.

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Curved Stair

Staircase with a gently sweeping flight.

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Curved Staircase with Stairwell Opening

Curved staircase with a central opening instead of a solid spindle.

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Custom Manufacturing

Staircase individually manufactured to the exact dimensions of the installation site.

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D

Dimension Limits

Maximum and minimum dimensions for stairs per DIN 18065.

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DIN 18040

German standard for accessible construction.

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DIN 18065

The principal German standard for building stairs.

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DIN 18334

German standard for carpentry and timber construction, including staircases.

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DIN 68368

Standard for hardwood lumber used in stair construction.

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DIN EN 15644

European standard for bespoke handcrafted wooden staircases.

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Double Bolt

Double bolts for load transfer without wall fixing.

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Double Quarter-Turn Stair (two 90° turns)

Continuous flight with two 90° changes of direction — standard U- or Z-shape.

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Durability Class

Classification of the natural resistance of wood to decay.

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E

EN 13501

European standard for fire-protection classification of building materials.

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Energy Expenditure in Stair Climbing

Climbing stairs requires significantly more energy than walking on level ground.

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Escape Stair

Staircase forming part of the escape route in an emergency.

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European Technical Assessment (ETA)

Europe-wide approval for non-standardised construction products.

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F

Fall Height

Vertical drop distance at open stair sides and landings.

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Fall Protection

Collective term for all protective devices against falls on stairs.

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Finger Clearance

Minimum clearance between the handrail and adjacent building components.

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Fire Retardancy

Fire-resistance classes for staircase components.

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Fire-Resistance Class (Stair)

Classification of stairs by fire-resistance duration.

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Fire-Resistant Stair

Staircase with high fire-resistance duration (F90/F120).

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Fire-Retardant Stair

Staircase with moderate fire-resistance duration (F30/F60).

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Flat Stringer Staircase

Stringer staircase with slim, flat side stringers in timber or steel.

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Flat-Roof Access Hatch

Fold-away ladder for flat-roof access.

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Floor Space Requirement

Space required by a staircase in plan view.

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Folded-Plate Stair

Stair with treads and risers joined in a continuous Z-shape from one material.

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Folded-Plate Staircase on a Central Beam

Folded-plate staircase supported by a central beam beneath the steps.

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Folding Space

Space required for unfolding loft ladders.

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G

Galvanised

Corrosion protection for metal parts through a zinc coating.

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Garden Stair

Outdoor staircase for bridging differences in terrain.

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Glass Stair

Staircase with transparent safety-glass treads.

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Glued Laminated Timber (Glulam Tread)

Stair tread made from glued timber laminations.

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Granite

Extremely hard natural stone for interior and exterior stairs.

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Graphical Tread Flaring (Drawing Method)

Drawing-based method to set tread goings on curved staircases — one of two established approaches.

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Guarding

Collective term for all types of fall protection on staircases.

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H

Half-Mortised Staircase

Stringer staircase with step ends exposed on one side.

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Half-Turn Single-Flight Stair

Straight flight with a 180-degree turn in the middle.

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Half-Turn Stair

Staircase with a 180-degree turn in the flight.

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Handrail

Ergonomic grip element mounted on or beside the railing.

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Hardwax Oil

Combination of oil and wax for natural protection of timber staircases.

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Harp Stair

Staircase with a cable-like support structure on the open side.

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Headroom

Clear height above the stair flight.

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Heartwood

Inner, harder part of the tree trunk — preferred for stair treads.

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Helical Stair

Curved staircase with an open stairwell opening.

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Hevea (Rubberwood)

Sustainable hardwood from the rubber tree — an increasingly popular stair timber.

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Housed Stringer Stair (Classic Variant)

Stringer staircase whose treads are housed into vertical grooves in the side stringers — most traditional variant.

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HPL (High Pressure Laminate)

High-pressure laminate — extremely durable surface material for stair treads.

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I

Impact-Sound Insulation

Measures to reduce sound transmission when walking on stairs.

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Intermediate Landing

Landing between two stair flights.

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K

Knot Grade

Timber grading by number and size of knots.

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L

L-Shaped Staircase (Quarter-Turn with Landing)

Two straight flights joined at a right angle by an intermediate landing — compare to winder stairs without landing.

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Lacquering

Surface sealing through a closed lacquer film.

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Ladder Feet

Protective caps on the feet of loft ladders.

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Laminated Safety Glass (LSG)

Multi-layer safety glass for stair treads and railings.

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Landing

Horizontal platform interrupting the stair flight.

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Landing Stair

Multi-flight stair whose straight flights are connected by one or more landings.

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Landing Step

Topmost step of a stair flight — marks the transition from stair to upper floor level. Its top surface is flush with the finished floor of the storey above.

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Larch

Hardest native softwood with a reddish colour tone.

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Left-Turning Stair

Staircase turning counter-clockwise when ascending.

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Legal Requirements (Stair Construction)

Legal framework for the planning and construction of stairs.

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Levelling Stair

Stair bridging small height differences between levels.

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Liming

White pigmentation of wood pores for a pale vintage look.

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Lining Frame

Frame for loft ladders set into the ceiling.

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Loft Ladder (Attic Access Overview)

Umbrella term for fold-away ladders giving access to attics — includes folding, sliding and retractable variants.

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Lower Rails

Horizontal bars in the lower area of a railing.

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M

Maple

Light, fine-pored hardwood with uniform texture for modern staircases.

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Marking (Stair Construction)

Transferring the workshop drawing onto the actual workpiece.

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Mathematical Tread Flaring (Calculation Method)

Calculation-based method to determine tread goings on curved staircases — formula-driven alternative to graphical flaring.

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Mortise Depth

Depth at which treads are mortised into the stringer grooves.

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N

Natural Stone Stair

Staircase with treads of natural stone.

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Nesting Process (Wood Machining)

Material-optimised cutting of multiple workpieces from a single panel.

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Newel Pipe

Central load-bearing pipe of a spiral stair.

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Nosing Projection (Overlap)

Overhang of a tread beyond the step below.

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Notched Stringer Staircase

Stringer staircase with steps set into visible cutouts in the stringers.

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O

Oak

The most popular and versatile timber in stair construction.

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Oiling

Natural surface treatment that penetrates deep into the wood.

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Online Stair Configurator

Web-based planning tool for pre-configuring an individual staircase.

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Open Side

Open side of a staircase without wall connection.

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Open Stair

Staircase without risers between the treads.

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Open Stringer

The stringer on the open side of a staircase.

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Outdoor Stair

Weather-resistant staircase designed for exterior use.

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Overlay Renovation

Renovation method by applying new treads over the existing surface.

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P

Paddle Stair

Space-saving stair with alternately offset treads.

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Parapet Handrail

Handrail mounted on a solid parapet wall.

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Parapet Railing

Fall protection mounted on a solid parapet.

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Pitch Angle

Angle of the stair flight to the horizontal.

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Powder Coating

Hard-wearing surface treatment for metal parts.

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Projection Depth

Total depth of the staircase in plan view.

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Q

Quarter-Turn

Stair flight with a 90-degree turn.

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R

Railing

Lateral balustrade of a staircase providing fall protection and a walking aid.

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Railing Handrail

Handrail mounted on the balustrade system of the staircase.

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Railing Height

Prescribed minimum height of stair railings.

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Railing Infill

Infill element between handrail and stair construction.

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Railing Rail

Horizontal connecting element in the railing system.

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Railing-Supported Stair

Staircase whose railing performs a structural function.

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Renovation Tread

Pre-fabricated, thin tread specifically for overlaying existing stairs.

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Required Stair

Staircase prescribed by building regulations as an escape route.

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Retractable Loft Ladder (Telescoping)

Extendable telescoping ladder — one sub-variant of loft ladders, used when space is tight.

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Right-Turning Stair

Staircase turning clockwise when ascending.

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Rise (Step Height)

Vertical distance between two successive steps.

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Rise-Run Triangle

Right-angled triangle representing the rise-going ratio graphically.

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Rise-to-Going Ratio

Ratio of step height to step depth.

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Riser

Vertical step element in closed staircases.

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Rotation per Step

Turning angle of each individual step in spiral stairs.

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Run Length

Horizontal length of a stair flight in plan.

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S

Saddled Stringer Stair

Stringer stair whose treads sit on top of the stringer.

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Scissor Ladder

Concertina-style loft ladder with scissor mechanisms between steps — extends and retracts vertically, ideal for attics where space for folding ladders is limited.

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Secondary Stair

Non-required stair serving ancillary areas — no building-code escape-route function, lighter dimensional rules.

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Self-Supporting Stair

Staircase without visible substructure, appearing to float in space.

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Single Quarter-Turn Stair (one 90° turn)

Single flight with exactly one 90° change of direction — standard L-shape.

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Sinus Stair Formula

Trigonometric formula for optimal rise-going ratios.

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Site Measurement

Precise measurement of building conditions for perfectly fitting staircases.

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Slide-In Stringer Staircase

Stringer staircase with treads slid laterally into the stringers.

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Slip Resistance

Slip safety of stair surfaces, classified per DIN 51130.

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Smoked Oak

Oak timber darkened to deep brown through ammonia fumigation.

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Solid Wood Stair (Full Construction)

Complete staircase — stringers, treads and risers made entirely from solid timber.

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Solid Wood Tread (Step Board)

Individual step board made from through-and-through solid timber, used on concrete or steel substructures.

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Space-Saving Stair

Compact staircase with reduced dimensions.

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Special Staircases

Staircases with unconventional construction beyond standard forms.

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Spiral Stair

Spirally curved staircase with a central load-bearing spindle.

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Staining

Colouring wood while preserving the visible grain.

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Stainless Steel

Corrosion-resistant steel for railings, handrails and connections.

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Stair Elevation (Workshop Drawing)

Scaled technical drawing of a staircase prior to production.

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Stair Enclosure

Building-code term for the space containing the staircase.

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Stair Flight

Continuous section of a staircase between two levels.

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Stair Formula

Overarching term for the calculation rules for comfortable stairs.

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Stair Lighting

Adequate illumination of staircases for accident prevention.

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Stair Nosing Profile

Protective profile on the front edge of stair treads.

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Stair Planning Process

Systematic process from site survey to production-ready drawings.

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Stair Renovation

Visual and functional renewal of an existing staircase.

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Stair Tolerances

Permissible deviations for rise, going and tread surface.

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Stair Width

Clear distance between handrails (or handrail and wall) — determines walking space. DIN 18065 requires at least 80 cm for required residential stairs.

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Stairs for Non-Residential Buildings (public / commercial)

Staircases in public, commercial or multi-family buildings — DIN 18065 strict minimum requirements apply.

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Stairs for Residential Buildings (up to 2 flats)

Staircases inside residential buildings with up to two apartments — DIN 18065 relaxed requirements.

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Stairs Within Apartments

Connecting stairs within a single dwelling unit.

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Stairwell

Enclosed building section housing the staircase.

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Stairwell Void

Free air space in the centre of a stair installation.

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Starting Step

First and lowest step of a stair flight.

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Steel Stair

Staircase with a steel support structure.

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Steep Staircase

Particularly steep staircase with minimal footprint, often as a secondary stair.

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Step Covering

Surface material applied to a stair tread.

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Step Length

Average stride length used as the basis of the rise-going ratio.

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Step-Ratio Formula

Rule of thumb for comfortable stairs: 2 × rise + going ≈ 63 cm.

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Storey Height

Height difference between two storeys.

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Storey Stair

Staircase connecting two storeys.

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Straight Single-Flight Stair

Stair flight without direction change or landing.

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Stringer Beam

Load-bearing beam beneath the treads.

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Stringer End Assembly

Construction of the stringer ends with newel posts and fittings.

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Stringer Stair

Stair type with one or two stringer beams as the support structure.

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Stringer Staircase (Umbrella Term)

Umbrella term for stairs carried between two lateral stringers — includes housed, saddled and freestanding variants.

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Stringer Support Systems

Connection solutions transferring stringer loads to ceilings and landings.

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Stringer Tie Rod

Tensioning screw fixing treads into the stringer mortises.

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Stringers

Lateral load-bearing components of a staircase.

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Structural Sizing of Stair Components

Load calculation proving the load-bearing capacity of individual stair elements.

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Support Bolt

Connecting elements between treads in bolt staircases.

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Suspended Stair

Staircase with treads hung from a structural handrail.

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System Stair

Modular, pre-fabricated staircase from a kit system.

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T

Telescopic Handrail

Moving handrail for folding and scissor ladders.

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Temporary Stair

Provisional staircase on construction sites.

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Thermally Modified Timber

Timber made durable through heat treatment.

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Three-Flight Staircase

Staircase composed of three straight flights with two intermediate landings.

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Toothed Stringer

Stringer with tooth-shaped cut-outs used on saddled staircases.

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Top Newel Post

Upper railing post — also called the landing post — at the head of the staircase; connects handrail to landing.

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Top Step

The uppermost step of a stair flight — also known as the exit step — where the handrail meets the landing.

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Tread

Horizontal, walkable part of a stair step.

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Tread Depth (Going)

Horizontal depth of a step, measured on the walking line.

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Tread Dimensions — Going and Length

Modern DIN 18065 base dimensions of the bounding rectangle of a tread (going × length).

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Tread Flaring — Overview for Curved Stairs

Umbrella concept for adjusting tread goings on curved flights — see graphical and mathematical methods below.

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Tread Grooves

Slip-resistant or decorative grooves routed into the tread surface.

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Tread Nosing (Leading Edge)

The front edge of a tread in the direction of travel.

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Tread Protection

Protective cover for treads during the construction phase.

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Tread Surface

Horizontal walkable top of a step — the going plus the overlap above the riser below. Together they form the safely usable tread area required by DIN 18065.

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Tread Thickness

Material thickness of a stair tread.

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Tread Width — Historical Term

Obsolete term for tread dimensions; superseded by separate going and tread length per DIN 18065.

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U

U-Shaped (Half-Turn) Staircase

Staircase with two parallel flights offset by a 180° change of direction.

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U-Shaped Stair

Two-flight staircase with an intermediate landing and 180° direction change — space-saving U-shape in plan.

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U-Value

Thermal transmittance coefficient of building components.

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Usable Stair Width

Clear width of a stair flight available for walking.

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V

Veneer

Thin timber face layer on a carrier material as an alternative to solid wood.

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W

Walking Line

Imaginary line representing a user's typical path along a staircase.

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Wall Handrail

Wall-mounted handrail without a freestanding railing — DIN 18040 requires 30 cm overhang and 50 mm finger clearance to the wall.

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Wall Stringer

The stringer on the wall side of a staircase.

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Walnut

Elegant, dark hardwood for representative staircases.

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Waxing

Traditional surface treatment with a silky-matt sheen.

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Winder Stair

Staircase with direction change via wedge-shaped steps.

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Winder Step

Wedge-shaped step in winding stair sections.

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Winder Tread

Wedge-shaped tread in winding stair sections.

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Winding

Direction change in the stair flight through wedge-shaped steps.

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Wood Moisture Content

Residual moisture in timber after technical drying.

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Workshop vs. On-Site Fabrication

Comparison of industrial prefabrication and on-site craftsmanship.

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Wreath Piece

Curved element of a handrail or stringer to resolve changes of direction.

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3D Planning & Visualization

Three-dimensional rendering of a planned staircase for clients and production.

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