Is there a name for outside stairs

Baunetz_Knowledge

Wooden stairs are differentiated according to the following types: semi-mounted stairs and block stairs. With the traditional block stairs, the solid wood steps, also called block steps, are pegged onto supporting stiles. Today they are almost always carried out with board-glued steps. As the name suggests, the steps on the saddled stairs are placed on the cheeks / support bars. For this purpose, the upper edges of the cheeks can be cut out and the steps on top and / or the steps can be placed on the support beam by means of a step wedge. The thickness of the steps is approx. 40 to 70 mm. Wooden stairs can also be designed as single, chiseled and pushed-in stairs.

Those who are interested in the technically correct connections and wood connections of traditional stairs will love the two classic books The stair and railing builder by Fritz Kress and Handcrafted stairs recommended by Ulrich Reitmeyer. We briefly present a small excerpt from these extensive works below.

  • According to the classic craftsmanship, treads and risers were inserted into one another via grooves on chiselled stairs, and in more complex solutions even with dovetail to limit the creaking of the stairs caused by the shrinkage of the wood.
  • The steps were fitted into the side cheeks with slightly narrower grooves (also because of the expected shrinkage), and the two cheeks were connected to one another by means of long screws, so-called cheek bolts.
  • The lower connection of the stringers or stiles (of saddled stairs) was statically held by means of a notch on the interchangeable beam of the stair opening against shear, either with a screw anchor or against the lowest railing post.
  • Connections between the entry post and the end of the cheek were often mortised or pegged.

The most difficult connections need to be loosened in the case of crooked staircases, as the stair builder's spatial imagination must be great both when tearing open the steps and when gluing and dowelling the bolster pieces together. With system stairs made of composite materials, today's crookedness can at least be roughly pre-configured using CNC machines.

The joining techniques must also encourage series production in order to be able to cope with the increasingly fierce price war on the market. Nevertheless, it must be possible to take into account the imponderables of excessively large shell tolerances for the floor heights by means of fitting. Stair builders create very precise measurements of the local situation and prefabricate almost everything in the company. The fasteners have to take these assembly processes into account: fewer and fewer tenons, almost no dovetail connections characterize our time, but more glues, dowel connections and semi-finished steel products such as angle brackets, screw bolts, etc. are used. This did not reduce the quality of the static load transfer.

The stair elements railing and handrail are also made from the renewable raw material wood, e.g. in the form of plywood panels as railing infills and wooden bars as load-bearing or filler bars. Wooden handrails are comfortable to grip and feel warm. Solid wood, glued planks or pressed wood-based materials are used for them.

Solid wood or laminated veneer lumber is predominantly used in stair construction. Below is a selection of types of wood and wood-based materials.

Solid wood (European species)

  • Conifers:
    Fir and spruce, which are suitable for less stressed house stairs;
    Pine, can also be used as a cheek with a splint;
    Larch, which can also be used outdoors because of its rich resin content;
    Douglas fir, which can also withstand weathering, but has no resin pockets
  • Hardwoods (in appropriate thicknesses are considered fire-retardant and can be used not only in living areas due to less wear and tear):
    Except for sapwood, oak is very suitable for building stairs, as it is a hard, robust wood;
    European beech is somewhat sensitive to moisture, otherwise also suitable for steps and handrails, cheaper than oak;
    Maple is more suitable for handrails and cheeks due to its light color and only medium-hard wood;
    Ash is often used in stair construction because of its grain;
    Because of its dark color, walnut is often used in the contract sector

Wood-based materials

  • Construction plywood BFU
    with goods surveillance seal and BFU-BU made with beech, cross-glued veneers (whereby a layer can consist of two veneers). The veneers must be arranged symmetrically to the center plane. Thickness of 10 to 40 mm, widths up to 1.50 m and length up to 2.50 m as load-bearing and stiffening panels. Only BFU-BU with a seal of approval is permitted for stair construction without individual verification.
  • Medium-hard fibreboard HFM and medium-density fibreboard MDF
    by pressing lignified fibers with (dry method MDF) or without (wet method HFM) adhesive, thickness 6 to 15 mm, width 1.25 m and length 2.50 m. May only be used with a seal of approval and examination in individual cases by the DIBT.
  • Laminated Veneer Lumber FSH
    Glued from approx. 3 mm thick softwood veneers, the grain is either generally parallel to the longitudinal direction of the panels or at least for the most part. Thickness: 21 to 75 mm, width up to 1.82 m, length up to 23 m; can be used in the same way as glued laminated timber as belt girders, etc., only to be used as a load-bearing part across the thickness with a seal of quality and building authority approval from the German Institute for Building Technology

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