Book Hotels in Stairs
Stairway, staircase, stairwell, flight of stairs or simply stairs are names for a construction designed to bridge a large vertical distance by dividing it into smaller vertical distances, called steps. Stairways may be straight, round, or may consist of two or more straight pieces connected at angles.
Special stairways include escalators and ladders. Alternatives to stairways are elevators, stairlifts and inclined moving sidewalks as well as stationary inclined sidewalks.
The step is composed of the tread and riser.
The balustrade is the system of railings and balusters that prevents people from falling over the edge.
Handrails may be continuous (sometimes called over-the-post) or post-to-post (or more accurately "newel-to-newel"). For continuous handrails on long balconies, there may be multiple newels and tandem caps to cover the newels. At corners, there are quarter-turn caps. For post-to-post systems, the newels project above the handrails.
Another, more classical, form of handrailing which is still in use is the tangent method. A variant of the Cylindric method of layout, it allows for continuous climbing and twisting rails and easings. It was defined from principles set down by architect Peter Nicholson in the 18th century.
The measurements of a stair, in particular the rise height and going of the steps, should remain the same along the stairs – with an obvious exception for winders.
The following stair measurements are important:
The easiest way to calculate the rise and run is to use a stair stringer calculator.
Ergonomically and for safety reasons, stairs have to have certain measurements in order for people to comfortably use them. Building codes will typically specify certain measurements so that the stairs are not too steep or narrow. Building codes will specify:
Jacques-François Blondel in his 1771 Cours d'architecture was the first known person to establish the ergonomic relationship of tread and riser dimensions. He specified that 2 x riser + tread = step length.
It is estimated that a noticeable mis-step occurs once in 7,398 uses and a minor accident on a flight of stairs occurs once in 63,000 uses. Some people choose to live in residences without stairs so that they are protected from injury.
Stairs are not suitable for wheelchairs and other vehicles. A stairlift is a mechanical device for lifting wheelchairs up and down stairs. For sufficiently wide stairs, a rail is mounted to the treads of the stairs. A chair is attached to the rail and the person on the chair is lifted as the chair moves along the rail.
(overview of Approved document K - Stairs Ramps and Guards)
Approved document K categorises stairs as ‘Private’, ‘Institutional or assembly’ and ‘other’
When considering stairs for private dwellings
Building regulations are required for stairs used where the difference of level is greater than 600mm
Steepness of stairs – Rise and Going - Any rise between 155mm and 220mm used with any going between 245mm and 260mm or any rise between 165mm and 200mm used with any going between 223mm and 300mm
Maximum Rise 220mm and Minimum Going 220mm remembering that the maximum pitch of private stairs is 42⁰. The normal relationship between dimensions of the rise and going is that twice the rise plus the going (2R + G) should be between 550mm and 700mm
Construction of steps - Steps should have level treads, they may have open risers but if so treads should overlap at least 16mm. Domestic private stairs are likely to be used by children under 5 years old so they should be constructed so that a 100mm diameter sphere cannot pass though the opening in the risers.
Headroom - A headroom of 2m is adequate. Special considerations can be made for loft conversions see paragraph 1.10 of the approved document for clarification on the 1.9 tapering to 1.8m
Width of flights - No recommendations are given for stair widths in the Approved document K for stairs but designer’s attention is drawn to approved document B: fire safety.
Length of flights - The approved document refers to 16 risers (steps) for stairs in shops or assembly building. There is no requirement for private stairs. In practice there will be less than 16 steps as 16 x 220mm gives over 3.5m total rise which is way above that in a domestic situation.
Landings - Level, unobstructed landings should be provided at the top and bottom of every flight. The width and length being at least that of the width of the stairs and can include part of the floor. A door may swing across the landing at the bottom of the flight but must leave a clear space of at least 400mm across the whole landing
Tapered steps - There are special rules for stairs with tapered steps as shown in the image Example of Winder Stairs above
Alternate tread stairs can be provide in space saving situations
Guarding - Flights and landings must be guarded at the sides where the drop is more than 600mm. As domestic private stairs are likely to be used by children under 5 the guarding must be constructed so that a 100mm diameter sphere cannot pass through any opening or constructed so that children will not be able to climb the guarding. The height for internal private stairs should be at least 900mm and be able to withstand a horizontal force of 0.36 kN/m
Stairs can take a large number of forms, combining winders and landings.
The simplest form is the straight flight of stairs, with neither winders nor landings. It is not often used in modern homes because:
However, a straight flight of stairs is easier to design and construct than one with landings. Additionally, the rhythm of stepping is not interrupted in a straight run, which may offset the increased fall risk by helping to prevent a misstep in the first place.
Most modern stairs incorporate at least one landing. "L" shaped stairways have one landing and usually change in direction by 90 degrees. "U" shaped stairs may employ a single wider landing for a change in direction of 180 degrees, or 2 landings for two changes in direction of 90 degrees each. Use of landings and a possible change of direction have the following effects:
Spiral stairs wind around a newel (also the central pole). They typically have a handrail on the outer side only, and on the inner side just the central pole. A squared spiral stair assumes a square stairwell and expands the steps and railing to a square, resulting in unequal steps (larger where they extend into a corner of the square). A pure spiral assumes a circular stairwell and the steps and handrail are equal and positioned screw-symmetrically. A tight spiral stair with a central pole is very space efficient in the use of floor area. Spiral stairs have the disadvantage of being very steep. Unless the central column is very large, the circumference of the circle at the walk line will be small enough that it will be impossible to maintain a normal going and a normal rise without compromising headroom before reaching the upper floor. To maintain headroom most spiral stairs have very high rises and a very short going. Most building codes limit the use of spiral stairs to small areas or secondary usage.
The term "spiral" is used incorrectly for a staircase from a mathematical viewpoint, as a mathematical spiral lies in a single plane and moves towards or away from a central point. A spiral staircase by the mathematical definition therefore would be of little use as it would afford no change in elevation. The correct mathematical term for motion where the locus remains at a fixed distance from a fixed line whilst moving in a circular motion about it is "helix". The presence or otherwise of a central pole does not affect the terminology applied to the design of the structure.
Spiral stairs in medieval times were generally made of stone and typically wound in a clockwise direction (from the ascendor's point of view), in order to place at a disadvantage attacking swordsmen (who were most often right-handed). This asymmetry forces the right-handed swordsman to engage the central pike and degrade his mobility compared with the defender who is facing down the stairs. Extant 14th to 17th century examples of these stairways can be seen at Muchalls Castle, Crathes Castle and Myres Castle in Scotland. Exceptions to the rule exist, however, as may be seen in the above image of the Scala of the Palazzo Contarini del Bovolo, which winds up anti-clockwise.
Developments in manufacturing and design have led to the introduction of kit form spiral stair. Steps and handrails can be bolted together to form a complete unit. These stairs can be made out of steel, timber, concrete or a combination of materials.
Helical or circular stairs do not have a central pole and there is a handrail on both sides. These have the advantage of a more uniform tread width when compared to the spiral staircase. Such stairs may also be built around an elliptical or oval planform. A double helix is possible, with two independent helical stairs in the same vertical space, allowing one person to ascend and another to descend, without ever meeting if they choose different helixes (examples : Château de Chambord, Château de Blois, Crédit Lyonnais headquarters in Paris). Fire escapes, though built with landings and straight runs of stairs, are often functionally double helixes, with two separate stairs intertwinned and occupying the same floor space. This is often in support of legal requirements to have two separate fire escapes.
Both spiral and helical stairs can be characterized by the number of turns that are made. A "quarter-turn" stair deposits the person facing 90 degrees from the starting orientation. Likewise there are half-turn, three-quarters-turn and full-turn stairs. A continuous spiral may make many turns depending on the height. Very tall multi turn spiral staircases are usually found in old stone towers within fortifications, churches and in lighthouses.
Winders may be used in combination with straight stairs to turn the direction of the stairs. This allows for a large number of permutations.
There is no newel at Loretto Chapel's spiral staircase (the "Miracle stair") in Santa Fe, New Mexico, USA.
A spiral staircase inside Cremona's Torrazzo, Italy.
Upward view of the Tulip Stairs & lantern at the Queen's House, Greenwich, United Kingdom.
Spiral stairway seen from below; Melk Abbey, Austria.
The earliest spiral staircases appear in Temple A in the Greek colony Selinunte, Sicily, to both sides of the cella. The temple was constructed around 480–470 BC.
Where there is insufficient space for the full run length of normal stairs, alternating tread stairs may be used. Alternating tread stairs allow for safe forward-facing descent of very steep stairs. The treads are designed such that they alternate between treads for each foot: one step is wide on the left side; the next step is wide on the right side. There is insufficient space on the narrow portion of the step for the other foot to stand, hence the person must always use the correct foot on the correct step. The slope of alternating tread stairs can be as high as 65 degrees as opposed to standard stairs which are almost always less than 45 degrees. The advantage of alternating tread stairs is that people can descend face forward. The only other alternative in such short spaces would be a ladder which requires backward-facing descent. Alternating tread stairs may not be safe for small children, the elderly or the physically challenged. Building codes typically classify them as ladders and will only allow them where ladders are allowed, usually basement or attic utility or storage areas not frequently accessed.
The image on the right illustrates the space efficiency gained by an alternating tread stair. The alternating tread stair appearing on the image's center, with green-colored treads. The alternating stair requires one unit of space per step: the same as the half-width step on its left, and half as much as the full-width stair on its right. Thus, the horizontal distance between steps is in this case reduced by a factor of two reducing the size of each step.
The horizontal distance between steps is reduced by a factor less than two if for constructional reasons there are narrow "unused" steps.
There is often (here also) glide plane symmetry: the mirror image with respect to the vertical center plane corresponds to a shift by one step.
Alternating tread stairs have been in use since at least 1888.
Stairway is a metaphor of achievement or loss of a position in the society, a metaphor of hierarchy (e.g. Jacob's Ladder, The Battleship Potemkin).
Staircase art is an art form practiced by a few devoted individuals around the world. A small vignette exists describing the art form here.