Ricardo Brown St. Mary High School STAIRCASES Ricardo Brown St. Mary High School

Objectives. Students will be able to: Explain what is a staircase State three function of stairs Distinguish clearly between at least eight (8) different types of stairs On a diagram identify at least ten (10) different parts on a stair

STAIRS Stairs are the medium through which a person can travel from one horizontal level to another horizontal level although it connects two different horizontal levels.

STAIRCASE: A stair is a set of steps leading from one floor to the other. It is provided to afford the means of ascent and descent between various floors of the building. The room or enclosure of the building, in which the stair is located, is known as staircase. The opening or space occupied by the stair is known as a stairway. In a domestic building the stairs should be centrally located to provide easy access to all rooms. In public buildings, stairs should be located near the entrance. Stairs may be constructed by timber, bricks, stone, steel or reinforced cement concrete.

Staircases provide access and communication between floors in multi-storey buildings, and are a path by which fire can spread from one floor to another. Staircase, therefore, must be enclosed by fire resisting walls, floors, ceiling and doors. It is desirable that the linings to the walls and the ceilings are non- combustible and of low flame spread. Another important aspect in the design of stairs is the strength aspect. It must be designed to carry certain loads, which are similar to those used for the design of floor.

STAIRS TYPES Single flight straight stairs Double flight straight stairs Quarter turn newel Half turn newel Open well stairs Dog legged stairs Bifurcated stairs Circular stairs Spiral stairs Geometrical stairs

DOUBLE FLIGHT STRAIGHT STAIRS Here the stairs posses two landings while running straight in the complete flight. QUARTER TURN NEWEL In quarter turn newel the stairs run straight in a flight and after reaching the landing the stairs it turns to either left or right at ninety degree and its runs again till it reaches the consecutive horizontal level.

Types of Stairs Quarter Turn

Stair Types

Quarter Turn Stair B C D E A F G H K I J L N M

Quarter Turn Stair

HALF TURN NEWEL In half turn newel stairs the stairs runs straight and after reaching the landing it turns to left or right and then climbs up to next two to three steps and reaches a landing and these steps again turns in the direction from where the user was approaching reaching finally to the consecutive horizontal level. OPEN WELL STAIRS These are like normal doglegged stairs but the only difference is that after reaching the landing the stairs ends up with a railing instead of the wall.

DOG LEGGED STAIRS Dog legged stairs are the stairs in which the user climbs up to a flight turns at one eighty degree and then climb stairs in opposite direction BIFURCATED STAIRS In bifurcated stairs the stairs runs at a flight an as it reaches the landing the stairs runs from left and right side reaching the same horizontal level these stairs are provided generally in atrium of a building.

CIRCULAR STAIRS The stairs made in in a circular form are known as the circular staircase.

SPIRAL STAIRS Those stairs which are in spiral form is known as spiral staircase.

GEOMETRIC STAIRS Geometric

PARTS OF A STAIR CASE

Technical terms associated with the design and constructions of stairs TREAD: it is the upper horizontal portion of a step upon which the foot is placed while ascending or descending. RISER: it is the vertical portion of a step providing a support to the tread. FLIGHT: this is defined as an unbroken series of steps between landings. LANDING: it is the level platform at the top or bottom of a flight between the floors. A landing facilitates change of direction and provides an opportunity for taking rest during the use of the stair.

RISE: it is the vertical distance between two successive tread faces RISE: it is the vertical distance between two successive tread faces. GOING: it is the horizontal distance between two successive riser faces. STRINGS AND STRINGERS: these are the slopping members which support the steps in a stair. They run along the slope of the stair. NEWEL POST: newel post is a vertical member which is placed at the ends of flights to connect the ends of strings and hand rail.

BALUSTER: it is vertical member of wood, metal or other material supporting the hand rail. HAND RAIL: it is the surrounded or moulded member of wood or metal following generally the contour of the nosing line, and fixed on the top of balusters.

2 Flights 1 Flight Definition – Flights Between Landings Dogleg Closed Riser Straight Open Riser

Half Space Landing Change stair direction 180⁰ Landing width = width of stair (min 750mm) Used in Dogleg Stairs

Quarter Space Landing Change Stair Direction 90⁰ Landing Width & Length = Stair Width Forms Quarter Turn Stair (min 750mm)

Intermediate Landing Allows the Stair to continue in same direction Required where more than 18 Risers May be used to give a rest Width = Stair Width Length = Stair Width or greater

Quarter Space Landing

Parts of Stairs

Parts of Stairs

Parts of Stairs

Parts of Stairs

Parts of Stairs

Parts of Stairs

Parts of Stairs

Parts of Stairs

Parts of Stairs

Parts of Stairs

Parts of Stairs

Class exercise Make a neat sketch of a timber staircase and label the following parts: tread, riser, newel, spandrel, handrail, baluster, string, landing, flight, wedge, glue block Explain the following terms: staircase, spandrel, landing, string, tread, riser. State three functions of a stair

Objectives. Students will be able to: List at least four materials from which stairs are made Use sketches to illustrate how timber stairs are fitted Determine the size of risers by calculation Determine the size of treads by calculation Determine the going of a stair by calculations.

STAIRS OF DIFFERENT MATERIALS TIMBER STAIRS: these stairs are light in weight and easy to construct, but they have very poor fire resistance. They are used only for small rise residential buildings. Sometimes, fire resisting hard wood of proper thickness may be used. STONE STAIRS: these are widely used at places where ashlar stone is readily available. Stone stairs are quite strong and rigid, though they are very heavy. Stone used for construction of stairs should be hard, strong and resistant to wear. The simplest form of stone stairs is those supported on both the ends, though an open well stair case can also be built.

STAIRS OF DIFFERENT MATERIALS BRICK STAIRS: these are not very common, except at the entrance. However, brick stairs of single straight flight are often made in village houses. The stairs consist of either solid wall, or also, arched openings may be left for obtaining storage space.

METAL STAIRS: stairs of mild steel or cast iron are used only as emergency stairs. They are not common in residential and public buildings, though they are strong and fire resistant. These are commonly used in factories, godowns, workshops, etc. R.C.C: these are the stairs widely used for residential, public and industrial buildings. They are strong, hard wearing and fire resisting. These are usually cast- in – situ and a wide variety of finishes can be used on these.

Timber Stairs

Metal Stairs

Concrete Stairs

Stone Stairs

Glass Stair

Combination of Materials

Winders Treads that are tapered Must have same rise as the flights Maximum of 3 treads per quarter turn Must be same width at centre on widths < 1m If stair > 1m same width 400mm from inside handrail

Winders

MODELS OF STAIRS

Stair Types

Stair Types Double Closed Stair

Stair Types

Stair Types

Double Open Sided Stairs

In this case one side is closed while the other is open

The Bracketed Stairs refers to decoration & Cut String Also Known as Cut String

Spine String Stair

GEOMETRICAL STAIRS

Definitions

Rise & Going must stay the same within flight

CHECK YOUR LEARNING

Stair Requirements

Stair Requirements

Calculate Stair No Restriction on Going Determine Total Rise = 2700 Best Going 2R + G Between 550 to 700 Midpoint = 625 Say 175mm Select suitable Rise = 2700/175 = 15.429 Divide Total Rise by Rise Either 15 or 16 Risers = 2700/15 = 180mm 2700/16 = 168.75mm Use 180mm is closer to 175mm

Determine Best Going BCA states that going must be within the range 2 x Rise (R) + Going(G) = 550 to 700 We can assume that the best answer is the Midpoint (550 + 700)/2 = 625 Best Going 2R + G = 625 Best Going G = 625 – 2R

Calculate Stair No Restriction on Going Best Going 2R + G Between 550 to 700 Midpoint = 625 Determine Total Rise = 2700 Say 175mm Select suitable Rise = 2700/175 = 15.429 Divide Total Rise by Rise Either 15 or 16 Risers = 2700/15 = 180mm (Use) 2700/16 = 168.75mm Determine Best Going 2R + G = 625 G = 625 – 2R Best Going for180 Riser 265 = 625 – 2 x 180 Either Rise 180 Going 265

Calculate Stair No Restriction on Going Use Rise 180 Going 265 15 Risers 14 Goings

Calculate Stair Restriction on Going Best Going 2R + G Between 550 to 700 Midpoint = 625 Preferred Rise 175mm Divide Total Rise by Rise = 2700/175 = 15.429 Either 15 or 16 Risers = 2700/15 = 180mm 2700/16 = 168.75 Use 180mm Determine Best Going 3800/14 = 271.43 + 2 x 180 = 631. 43 (Closest) 3800/15 = 253.33 + 2 x 168.75 = 591 15 Risers 14 Goings Use Rise 180 Going 271.43

Calculate Stair Flight with Quarter Turn Stair width 900mm Once an Intermediate Landing is introduced the top flight becomes constrained

Calculate Stair Flight with Quarter Turn Best Going 2R + G Between 550 to 700 Midpoint = 625 G = 625 – 2R Stair width 900mm Preferred Rise = 165mm 2700/165 = 16 .364 16 2700/16= 168.75 (3.75 Diff) 2700/17= 158.824 (6.176 Diff) Use Rise = 168.75 Best Going = 625 – 2R = 625 – 2 x 168.75 = 287.5 1800/287.5 = 6.261 6 1800/6 = 300 (12.5 Diff) 1800/7 = 257.143 (30.357 Diff) Rise = 168.364 Going = 300

Calculate Stair Flight with Quarter Turn Best Going 2R + G Between 550 to 700 Midpoint = 625 G = 625 – 2R Stair width 900mm Preferred Rise = 165mm 2700/165 = 16 .364 16 2700/16= 168.75 (3.75 Diff) 2700/17= 158.824 (6.176 Diff) Use Rise = 168.75 Best Going = 625 – 2R = 625 – 2 x 168.75 = 287.5 1800/287.5 = 6.261 6 1800/6 = 300 (12.5 Diff) 1800/7 = 257.143 (30.357 Diff) Rise = 168.364 Going = 300

Calculate Stair Constrained Flight with Quarter Turn Best Going 2R + G Between 550 to 700 Midpoint = 625 625- 2 x 180 = 265 Stair width 900mm From Previous we know 15 Risers at 180 Length of 1st Flight = 2700 - 900 Divide by Best Going = 1800/265 = 6.79 Going Either 1800 /6 = 300mm 1800/7 = 257mm 257.14 is Closest to 265

Calculate Stair Constrained Flight with Half Space Landing Preferred Riser 170mm 3600/170 = 21.176 21 3600/21 = 171.429 3600/22 = 163.636 Use 171.429mm Best Going = 625 – 2R = 625 – 2 x 171.429 = 282.142 Length of 1st Flight = 4050 – 900 = 3150 Divide by Best Going = 3150/282.142 = 11.16 11 3150/11 = 286.364 - 3150/12 = 262.500 Use 286.364 Stair width 900mm

Calculate Stair Constrained Flight with Half Space Landing Preferred Riser 170mm Rise 171.429mm Going 286.364 Stair width 900mm

Calculate Stair Constrained Flight with Quarter Turn Winders Preferred Riser 170mm 4100/170 = 24.118 24 4100/24 = 170.833 25 4100/24 = 164 Use Rise 170.833 Best Going 625 – 2R = BG 625 – 2 x 170.833 = 283.334 2650/ 283.334 = 9.353 2650/9 = 294.444 (USE) 2650/10 = 265 Rise 170.833 Going 268.75 Stair width 900mm

Calculate Stair Constrained Flight with Quarter Turn Winders Preferred Riser 170mm 4100/170 = 24.118 24 4100/24 = 170.833 25 4100/24 = 164 Use Rise 170.833 Best Going 625 – 2R = BG 625 – 2 x 170.833 = 283.334 2650/ 283.334 = 9.353 2650/9 = 294.444 (USE) 2650/10 = 265 Rise 170.833 Going 294.444 Stair width 900mm

Calculate Stair Constrained Flight with Half Space Landing Stair width 950mm Preferred Riser 170mm 3400/170 = 20 3400/20 = 170 Rise Best Going = 625 – 2R = 625 – 2 x 170 = 285 2400/285 = 8.421 8 2400/8 = 300 (15 Diff) 2400/9 = 266.667 (18.3 Diff) Rise 170 Going 300

Calculate Stair Constrained Flight with Half Space Landing Stair width 950mm Preferred Riser 170mm 3400/170 = 20 3400/20 = 170 Rise Best Going = 625 – 2R = 625 – 2 x 170 = 285 2400/285 = 8.421 8 2400/8 = 300 (15 Diff) 2400/9 = 266.667 (18.3 Diff) Rise 170 Going 300 With all examples either answer will comply and you should consult with your client and/or Architect

Determine Steel Square Mathematically 40mm Margin

Determine Steel Square Mathematically

Determine Steel Square Mathematically Stair Pitch = 29.54⁰ Zoom In

Determine Steel Square Mathematically Stair Pitch = 29.54⁰ Margin Line

Determine Steel Square Mathematically This angle must be the same Stair Pitch = 29.54⁰

Determine Steel Square Mathematically This angle must be the same Stair Pitch = 29.54⁰ Sin Ѳ = Adjacent / Hypotenuse = 40 ÷ X X = 40 ÷ Sin 29.54 X = 81.131

Determine Steel Square Mathematically This angle must be the same Stair Pitch = 29.54⁰ Sin Ѳ = Adjacent / Hypotenuse = 40 ÷ X X = 40 ÷ Sin 29.54 X = 81.13

Determine Steel Square Mathematically Set Out For Steel Square Going Going + Margin ÷ Sin Ѳ = 300 + 40 ÷ Sin 29.54⁰ = 381.13mm Ѳ

Determine Steel Square Mathematically Set Out For Steel Square Rise Ѳ

Determine Steel Square Mathematically Set Out For Steel Square Rise This Angle must = 90 - 29.54 Ѳ

Determine Steel Square Mathematically Set Out For Steel Square Rise This Angle must = 90 - 29.54 This Angle must = 29.54⁰ Y = 40 ÷ Cos 29.54⁰ Y = 45.9763 Ѳ

Determine Steel Square Mathematically Set Out For Steel Square Rise This Angle must = 90 - 29.54 This Angle must = 29.54⁰ Y = 40 ÷ Cos 29.54⁰ Y = 45.9763 Ѳ

Determine Steel Square Mathematically Set Out For Steel Square Rise Rise + Margin ÷ Sin Ѳ = 170 + 40 ÷ Sin 29.54⁰ = 170 + 45.98 = 215.98 Ѳ

reference Kumar, G. Nagesh - Staircases