- Spoiled for choice
- Materials on demand
- Families of stairs
- The importance of the hopper
- General volumetry
- Sizing of the steps
- Give priority to the fold
- The walking nose
- Modern style
- Anti-falling coatings
- Install guardrails
- Free inspiration
- On console
Miller's ladder, unique piece of an architect or fly masonry on the spot... Whether measures taken or aesthetic criteria, the solutions are many and varied.
Spoiled for choice
Spiral, straight, one or two flights, one or two quarter turns, balanced, baluster, with or without risers, metal, wood, concrete or composite, rustic or contemporary... The stairs occupy a place choice in the decoration of the house and are declined to infinity.
This profusion does not always facilitate the choice. Especially since the installation of a staircase does not depend solely on aesthetic criteria. There are indeed rules of calculation and implementation to respect to avoid a model impractical or incompatible with the desired use. For example, a spiral staircase will certainly not be the most convenient way to move grandma's cabinet or grand piano!
Materials on demand
As for materials, it's more a matter of taste than of constraints (except the weight in certain configurations). If wood is the choice, softwood species, such as pine, should be avoided, except for occasionally used milling ladders. They will prefer hard woods such as beech, oak, ash or tauari (from South America).
Steel, easy to combine with other materials, is increasingly present in contemporary decorations. As for the masonry stairs, concrete or on Saracen vault (plaster and brick), they offer many possibilities.
Families of stairs
In this set, we can nevertheless identify four large families. The straight staircase, the simplest to design. The quarter-turn staircase which, like the right, presents the first flight of steps facing a passage. The swinging staircase is balanced, that is to say composed of straight and trapezoidal steps (or intermediate level) which is easily installed between the walls of an entrance. Finally, the spiral staircases where all the steps are organized around a central axis.
The importance of the hopper
In many cases - unless there is unrestricted room - it is the space available in the floor of the upper floor for the passage of the staircase, ie the hopper, which determines the choice. Thus a long and narrow opening is suitable for a straight staircase. If it is shorter, a quarter turn staircase will be more suitable, while the rotating two-quarter will settle rather on a square surface.
As for the helical, it can be installed in small hoppers (140 cm minimum side anyway!). It is also important to check the position and direction of opening of doors and windows, the direction of the staircase - right or left - for rotating models. Also check the ceiling height or slope of the roof under the eaves not to bump your head.
Whatever the choice, taking measurements is a crucial step. The following should be taken into account: the general volumetry of the staircase, ie the height of the finished floor; the thickness of the slab between the ceiling of the lower storey and the floor of the upper storey; the length and width of the hopper and the size of the stairs.
From this set will result the average slope, which should generally be between 25 and 40° (compared to that of a miller scale that can display 60 to 70°). In all cases, the inclination must be constant. If applicable, the intermediate levels will be included in the design because they are decisive in the volumetry of the staircase. Namely: a volley must not exceed twenty-two steps.
Sizing of the steps
This element is crucial for comfort. Experience has shown that a staircase is safe and pleasant to practice if the values of height of walk (h) and depth or tread (g) meet the following formula: 2 h + g = 63 cm (rule called Blondel).
These 63 cm correspond to the average amplitude of the human step which is between 60 and 66 cm. According to this formula, the ideal staircase has a walking height of 17 cm for a lap of 29 cm (17 x 2 + 29 = 63). In practice, the height of the steps is often between 16 and 20 cm, and the depth of the tread between 28 and 30 cm. The starting march, often longer or lower, cheats slightly compared to Blondel's rule to give progressivity to the ascent.
Take into account also, the step (useful width) which will preferably exceed 70 cm, and the escapement (height under the edge of the hopper) still exceeding 2 m to allow the passage of a standing person. There are also unavoidable standards imposed by the legislator, such as the height of the ramps fixed at 91 cm (101 cm for the balustrades), or the space between two balusters (bars) determined at 11 cm so as to prevent a child from go over there.
Give priority to the fold
The lap, the depth of the walk, is more important than the height. Better sometimes to increase the latter and get a lap of at least 22 cm, more comfortable on ascent and descent.
The walking nose
The stair nosing, absent from most of the stairs of contemporary design, is the protruding part at the front. Its overhang is of the order of 2.5 to 3 cm. It can be in the extension of walking (solid wood) or consisting of a patch.
A staircase balanced and without risers, very contemporary spirit. Note the height of the ramp: 91 cm on a staircase, 110 cm on a landing.
The covering of the steps must be slip-resistant. The choice of stair noses is particularly important: avoid bonded coatings that may have dangerous thicknesses in case of detachment.
For safety reasons, non-enclosed stairs must have guardrails on each side. Between two walls, a minimum width of 80 cm (passage of bulky object) must be provided.
The stairs with central stringer allow all types of forms. This option, coupled with the absence of risers, allows to "lighten" the whole, while giving it a contemporary look.
The escalator is a variant of the staircase backed with steps embedded in the wall. Here, the steps are fixed on consoles, themselves secured to the wall. The other end is left overhanging with or without silt.