The contents
About the comfort of the dream of all property owners, regardless of material wealth. You need to thoroughly treat the issue arrangement of the stairs if the house several floors, or to use the house will be extremely uncomfortable.
The stringer – bearing element, which represents an inclined beam on which are mounted the fences and steps. Is this item on a flight of stairs and gives the entire structure strength, making it a true monolith. The simplicity and reliability of design features that have made these ladder structures are in demand.
Species ↑
Answering the common question: «what is the stringers for stairs», it should be noted that there are several variants of these elements:
- broken (for structures with multiple spans, angled);
- direct (used for the main single-span structures);
- involute (spiral) designed for curved spiral marches.
The bearing elements are in the center (single) or on each side of the structure (two elements when the width of the staircase 1.5 m).
The materials ↑
Original wooden stairs to the stringers running from the following materials:
- natural wood;
- reinforced concrete or concrete;
- metal.
Whichever material is used for the arrangement of the steps of: modern polymers, aluminum, wood, cast iron, stone, for the manufacture of the frame for future ladder designs choose profile pipe, I-beam, channel.
Expect support beam ↑
In order that the design was comfortable, durable, and beautiful, creating the stringers for the stairs with their hands it is important to carry out the correct calculations. The essence of the calculations is to determine the number of stair steps-width podstupenki, the height of the interval between them
Algorithm:
- the calculation of the length and height of the stair design. When you create a single-span system equipped with the direct elements, the span length should be no more than 4.5 m. the Height is determined based on the size of the ceiling. Suppose that the ceiling of 3.1 m, add 15 cm to the design of flooring, insulation, obtained the height of the steel stairs on the stringers – 3, 25 m;
- calculate the number of stages. Step allowed height of 16-22 cm, width 28-35 cm In length 4.5 m, divided by the size of one step, you get 15 pieces. Divide the height of the ladder system 3,2. 5 m by the number of steps (15), we obtain the height of one stage of 21.6 cm;
- mark up itself support beam. Whichever material you choose for ladder supports (wood, metal) must perform a special layout of the main beams. A wooden staircase on strings is tokenized with the use of a square. Previously it measure the height and width of a step (according to our calculations 28 cm and 20.3 cm);
- sawing of wood the stringers. The main breeds that are suitable for their production: pine, oak. Among the disadvantages of oak – the high cost and substantial weight. Pine stringers cheaper compute the stringer of the ladder from the tree, choose a Board thickness of 40 mm. in the manufacture of their efforts, the new ladder system, use a circular saw or a jigsaw;
- installed stage. Before you will mount the steps, spend a full calculation of metal stringer for stairs, and also select the material under the stage. Mount stair installations on metal supports running welded connections or bolts. Wood options allow you to mount the stairs with screws, screws and also with the use of horses. Horses called tab on a support beam that is fastened with ties, screws, dowels. If the stairs are mounted on two stringers, the step and filly are mounted on the dowels, made from beech, which are screwed on the screws.
- installed balusters. The attachment of the balusters mounted directly to the stringers or steps that would require dowels or tie. Fixing of balusters for stairs with metal stringers should be durable, because the quality of the installation depends on the reliability of the entire structure. The best would be the use of dowel and tie a length of 6-7 cm, in this case the balusters will be protected from possible fall.
- the choice of the number of the stringers. Modern stairs on steel kosouram allow the use of 1-3 of the stringers, given the width of the structure. In most cases wooden structures involve the use of two side stringers. Standard stairs with metal stringers with their hands can do, knowing that from the Central location of the supporting elements is a metallic sole, to attach the stairs.
Installation of cast iron support elements is a complex undertaking, it is better to take the help of professionals. Picking up the mount on such a structure, consider doing a drawing of the stairs on the stringers that it is necessary to pay attention to one Central and two side mounts.
How to calculate stair construction ↑
- distance between floors;
- height podstupenki, the depth of the tread;
- the length and width of the stair system;
- weight (8-9 kg).
For safety requirements, stringers for stairs from metal, must be the depth of 30 cm to determine the load on the step, takes a maximum weight of 400 kg. Multiplying the standard rate of 135 kg on a special factor of 1.1 (a measure of reliability), we obtain 148,5 kg. Add to this figure the maximum weight, multiplied by a factor of 1.4 (560 kg), the result -708,5 kg is the load on profiled metal element.
Using the formula I = 5.2 x b x Q x L / E
b – the width of a step, cm;
Q – load (708,5 cm);
L is the length of the reference beam, cm;
E-Modul of elastic forces, amounting to 2100000 kg/cm?
SNiP allows the use of profile thickness 3 mm, size 140 x 60 mm. For ladder structures with several marches, carried out the calculations separately for each span.
Conclusion ↑
Stair constructions the support members provide a huge space savings. But before you think about layout, how to lay out a stringer for wooden staircases, rate the features of your home: the availability of storage, the height of the ceiling.
- Single span ladder system is not suitable for high ceilings, it is unlikely you will be able to make it completely safe;
- if you choose for steps of a natural tree, be sure to cover it with a protective impregnation or lacquer;
- to ensure complete safety of movement on ladders children and the elderly, install the balusters;
- steps and podstupenki required before varnishing or impregnation, process with fine emery paper;
- in order to avoid mistakes during the construction of the ladder system on the support beams, be sure to perform preliminary calculations.
