Sunday 11 September 2011

Wood floors: existing types

VERSION EN ESPAÑOL


As a preliminary step to start talking soon about wood floors in decorational, we are going to explain the different types available and what are their characteristics and differences.

Wood has several features that make it very useful for construction, and thus the man used regularly:

  • Present throughout the world, is very easy to obtain and is regenerable.
  • It is not a dense material, so transportation is not complicated.
  • It is very tough as a structural element (eg beams).
  • It can be easily manipulated, allowing to get items in various ways (eg tables).

Because of the development of new materials and building systems, the use of wood as a structural element has decreased, but it is still widely used in decorative elements, including floor and wall coverings, which as you know are the type of products on which we speak in decorational
.


However, one feature of the timber must bear in mind when using it: it is a highly hygroscopic material, ie has a great capacity to absorb and give up moisture from/to the environment. And with changes in its humidity, wood undergoes a remarkable dimensional variation: when the humidity is high the wood swells, and when humidity is low it shrinksThis happens just with the moisture, it is not necessary that liquid water is present, and this process happens continuously, no matter how many years have passed since the wood was obtained.


If we take a wood board, this variation happens mainly in the width and height, and in a much smaller proportion happens in the length of the table. As a guide, a table of 10 cm in width can grow or shrink several milimeters with changes in humidity, although the value depends on the type of wood.





This characteristic has forced the evolvution of wood floors, from traditional solid to modern floating floors. Below we explain the different types, their characteristics and differences.

Solid floor
The boards used are made of solid wood, obtained directly from the sawing of the log.

To ensure the stability of floor with moisture variations, the planks shall always be fixed to the sub-floor. Therefore, these floors can only be installed glued to de sub-floor or nailed to lower battens.

Traditionally, since the 17th century in French palaces, this kind of floor has been used in small format boards glued to the substrate. From about 1880, larger boards with perimetral tongue and groove to ensure the joins between boards, and to avoid level differences in their surfaces when the changes in their humidity (and therefore size) happen over the years.


If the boards do not incorporate a protective treatment before installation -see Wood Floors: types of treatments- usually treatment is applied over the installed floor. A previous sanding to the entire surface is needed to eliminate any level difference between boards.


Over the years, the continuous movement of the boards by changes in humidity can favor the appearance of gaps between them. This is a normal proccess that cannot be easily avoided.




When, due to use of the floor, the surface treatment gets in bad condition, a repair treatment can be done. Sanding the entire surface to remove all existing treatment and can be applied a new treatment. As the sanding process retires less than 1mm of the wood floor's surface, it can be repeated several times until the sanding reaches the tongue of the boards (if available) or 50% of the thickness of the board. If we suppose the renovation procces is needed after 15 years of use, and it can be done at least 4 times, the wood floor will last 60 years.

Multilayer Parquet
Since solid wood floors are difficult to install because it's necessary to fix them to the support, in 1941 a new wooden floor was developed, composed several layers arranged in an angle of 90 degrees to get the dilatation of wood contained so the boards together are much more stable than a solid wood floor.



As we see in the picture, the middle layer is the thickest of all, about 10mm, and is made up of narrow slats positioned transversely to the board and spaced to allow the continuous expansion and contraction of their width due to moisture changes inside the floor without being noticed.


Over the middle layer is fixed the wear layer, which is the visible layer of floor and usually has 3 or more millimeters. How it is thin compared to the middle layer, when the wood in the surface layer tries to expand or contract due to humidity changes, the middle layer as it is "attached" to it, being placed at 90 degrees. Over this layer is the protective surface treatment, usually applied in the production proccess. This type of wood floor also allows various floor sandings to renew the surface until the wear layer is removed completely.


The back layer is necessary to get the whole board is stable. The wood in this layer also has a 90° to the middle layer. With this construction of the boards, they get to be much more stable, so there is no need to fix them to de subfloor and can be placed in a floating installation -see Wood Floors: installation systems [soon]- so today this the most widely used type of wood floor.


Veneer Parquet
As an evolution of multilayer parquet, in 1995 appeared the first veneer floor.



In this case, the intermediate layer is formed by a board of pressed wood fibers, which has a higher impact resistance than conventional lumber.




Over it lies the top layer of venner, which is the visible one. This layer is less than 1mm thick, with two objectives: reducing the cost and improving impact resistance. When an object hits the surface of the floor, the wood in the top layer tends to warp, but it is a thin layer and under it there is a much more hard material, the fiber board, that significantly improves the impact resistance of the floor.


As in the case of multilayer parquet, the back layer is necessary to give stability to the board. 


This type of wood floor does not allow for subsequent sanding because of the very small thickness of the surface veneer, so once the surface treatment is damaged -it can easily last for 20 years in a home- is necessary to replace the floor. As the surface treatments are increasingly resistant, they allow the use of this type of floor even in public places.

Laminate Floor
While generally this floor is regarded as wood floor, mainly because its appearance mimics it and the form of installation is similar, we can not formally consider a laminate floor as a wood floor because the visible image of the surface consists of a decorative paper impregnated with resins (layer called overlay) that provide surface resistance. Its manufacturing process has evolved over the years. Currently there are mainly two different processes that lead to the Direct Pressure Laminate (DPL) and High Pressure Laminates (HPL). As this type of floor is enterely manufactured, a classification for resistance can be established. Coming soon we will post an entry in decorational explaining the different existing laminate floors and their classifications.




The main difference between HPL and DPL is that HPL is manufactured in advance and separate the surface layer (decorated paper + overlay), which is then fixed to the board giving it greater resistance to wear and impact.


We hope these brief descriptions have served you to have clearer ideas about different types of wood floors, and we wait for you in the next entry of decoracional.


Related posts:
Wood floors: Surface treatment
Wood floors: Supreme Kährs series

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