Plank floor

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Old pitch pine floor board

A plank floor , also known as a strip floor or a belt floor , is a wooden floor made of boards , in room lengths or varying lengths. It is the oldest form of wooden floor , along with the wooden paving (also called heeled floor) made of short front wood sections.

A later development are parquet floors , which are composed of wooden rods that are usually shorter than a meter and are usually prefabricated from hardwood with a circumferential groove or with milled tongue and groove .

The floorboards

Planks can be made from any type of wood that can be cut to the desired width without cracking. In contrast to boards for general use which is round timber in the preferred grain patterns separated so that predominantly vertical annual rings of the finished floorboard standing extend. Lying annual rings, especially in fast-growing softwood, can lead to a shallow, splintery layer of wood coming off the surface of the floor along the course of the annual rings.

Dry and dimensionally stable wood is desirable in order to obtain a long-term surface that is free of offsets and joints.

Traditionally, solid boards with a thickness of 21 to around 40 mm and a width of 80 mm or more are used. ( Sawn timber with a thickness of more than 40 mm is no longer referred to as a board , but as a plank .) Similar to parquet planks , floor boards are now usually manufactured with a groove cut into one or two sides and a milled tongue on the opposite side. Due to the tongue and groove connection , point loads are distributed over several boards lying next to one another, so that even thinner boards from a thickness of around 15 mm can be used. If gaps occur in the installed floor, they may at gespundeten filled boards with a putty or wood strips ( "Holzspliss") ausgespant be without the joint material to that later released again, as is the case with historic boards that move against each other .

The size of the planks is limited by factors such as trunk length and width, shrinkage behavior of the wood, size of the drying chamber and the transport options. Often lengths of up to 15 m and widths of up to 60 cm are possible. Particularly wide and long solid wood planks are called castle planks . High-quality wooden floors are often laid across the length of the room.

Today, planks are also glued in two or more layers like veneer or glued laminated wood and are often referred to as country house planks in the trade .

  • There is hardly any waste during production, as the layers are endlessly joined together using a finger joint before they are glued .
  • By gluing together several pre-dried layers, a suitable wood quality can be selected for the base and wear layers. This results in a very dimensionally stable plank floor.
  • Solid and flawless wood with an even grain is selected for the visible and usable surface, while residual wood can be used in the other layers.
  • The top layer should be at least 8 mm thick so that the wooden floor can be sanded several times for renovation without sanding through the wear layer.

Pine, larch, spruce or fir are mostly used as softwood . The imported woods pitch pine and oregon pine ( Douglas fir ) were used more frequently in old buildings around 1900 . High-quality floors are made from hardwood or tropical woods.

Bunging in wooden planks, which can also be used on the front.

Before the advent of sawmills , planks were sawn by hand. Very wide planks were sawn from the middle of the trunk, as these so-called "heart boards" are less likely to warp. This enabled boards with widths of up to one meter, which result in a similarly evenly laid and stable floor as pounded boards. the formation of cracks was accepted. With the Industrial Woodworking (in Germany as from 1850) the boards were thin and uniformly made wide and were usually by a tongue and groove connection gespundet . The length was measured so that it corresponded to the length of the room across the beam position. In the case of very large rooms or corridors, the boards were joined lengthways on a ceiling beam.

Instead of the variable lengths that were usual in the past, country house floorboards and many solid wood floorboards are now supplied with a fixed length of around two meters and are sponged on all sides. Thanks to the tongue and groove connection between the boards, they do not have to be pushed onto the joists and can therefore be laid continuously without waste.

Construction and function

Types of mortise and fixing of plank floors

With traditional wooden beam ceilings , the floorboards were nailed directly to the ceiling beams. In the case of pounded planks, pins (nails with a small head) are usually driven diagonally through the tongue so that the nail is not visible on the surface. When renovating old buildings , uneven and bent beam layers can be compensated for in height by appropriately cut lining wood (strips tapering towards the end). If the side of the beam is accessible, the height compensation can easily be made by screwing planks to the side of the beam. On sagging beams, the boards are attached to protrude upwards opposite the beams so that the planks are supported by the planks alone at these points.

Up to 2008, masonry structures with up to 2 full storeys and stiffening walls according to DIN 1053 Part 1 Fig. 2.1 could be assumed to be a “ pane according to DIN 1052-1 without mathematical proof ” according to DIN 1052: 1988, if

  • load-bearing ceiling formwork (e.g. floorboards) made of boards with a width of at least 12 cm or wood-based panels are available,
  • Tie rod according to DIN 1053 Part 1, Section be arranged and
  • the building is stiffened continuously from wall to wall by walls in accordance with DIN 1053 Part 1, Table 3.

Historically, static stiffening was also achieved by laying boards at a 45 ° angle to the beams or by using additional, diagonally laid steel strips. Today this is mostly done by sub-floors made of wide material or gypsum fiber boards .

If planks are attached directly to the wooden beams, they transmit impact sound and, to a lesser extent, airborne sound to adjacent rooms. Rooms below can be protected from the transmission of noise by a suspended, acoustically decoupled ceiling. In purely wooden structures, however, the ceiling beams transmit the impact sound through their supports into the entire structure. In this case, as well as if a suspended suspended ceiling is to be dispensed with in solid buildings, the plank floor should not be attached directly to the wooden beams.

As a rule today, wooden supports are first placed loosely on the ceiling joists, which are decoupled from the joists by intervening impact sound insulation strips (e.g. felt ). After laying the floor, the wooden supports are only screwed to the boards. It is particularly important to ensure that no screw is screwed through the impact sound insulation into the ceiling joist. As an alternative, planks can be laid on a base layer made of panel material or on a well-dried screed . Traditionally, the battens were often placed loosely in the filling of blast furnace slag , which was placed in the spaces between the beams for fire and airborne noise protection and, for example, was supported by a sub-floor made of inserts underneath .

A plank floor on solid ceilings such as concrete requires storage timber that can lie on the raw floor or be glued directly to the screed with elastic adhesives . The surface either remained untreated or was sealed with ox blood or floor wax . Sealing with clear lacquer was added later, and oiling has recently become an alternative.

In the present, multi-layer planks, which are offered as sponged or also as click or lock systems, are laid or glued floating on screed or sub-floors. Such floor structures no longer have a load-bearing or static function.

Web links

Wiktionary: floorboards  - explanations of meanings, word origins, synonyms, translations


  1. If splinters come off the surface of the wooden floor, the floor can be sanded again. However, it is to be expected that splinters will form again after a while. This is prevented by sealing the floor. The wood is then protected by the synthetic resin layer, which itself wears out and has to be replaced after a few years. Alternatively, the affected areas can be worked with rotating abrasive brushes whose abrasive bristles remove the splinters. In particular, carpenters who are involved in the renovation of old buildings or in the preservation of historical monuments have appropriate brush machines. Brushing the floor vividly emphasizes the grain. When it comes to an even appearance, the entire floor should be treated.
  2. Jan Nicklaus: Filling floorboard joints , September 5, 2019
  3. Dr. Holger Schopbach: Ceiling and roof panes according to EC5-1-1 , Eurocode 5, In: or Zeitschrift Holzbau - Die neue Quadriga 3/2016, p. 47
  4. Prof. Dipl.-Ing. Erich Milbrandt: Bracing wooden beam ceilings in masonry construction - Part 2/4 , In:, October 15, 2001