Modern interior rigid floor coverings evolved from slate, stone, ceramic, clay and other types of tiles, loosely or tightly placed, or grouted, onto dirt or clay substrates, or placed onto or adhered to wood or cementitious substrates using cementitious liquids and pastes that dry or otherwise cure into solid form. These early types of rigid flooring are still commonly used. Modern flooring adhesives still include these above types but there has generally been a shift toward using polymers, either alone or in combination with cementitious materials, to adhere rigid floor coverings to the respective substrate floor. Rigid composite laminate flooring systems have also become quite popular in recent years and are a modern example of tightly placed interlocking pieces that are not normally bound to the substrate floor with adhesives.
The various types of rigid floor coverings remain important but less so than in earlier times. Flexible floor coverings now form a large part of the flooring market. Rigid wall coverings evolved similarly to floor coverings, with ceramic tiles often used in kitchens and bathrooms being a common modern example of a rigid wall covering system.
Early interior flexible floor coverings that could be rolled or bent includes animal skins, mats or carpets made from vegetation, animal hair such as wool, and other textiles, fibrous materials and fabrics that are made into various woven and non-woven types. There is a wide range of carpet types and styles that have evolved along different paths in various parts of the world. Carpets, linoleum, vinyl and flexible laminate flooring, now often made from synthetic polymers, have evolved from the earlier types.
Interior flexible floor coverings are loosely placed or adhered to substrates using tacks, nails, screws and/or other types of mechanical fasteners. They are also able to be adhered to substrates using liquid or paste adhesives that dry or otherwise cure into rigid or flexible (elastomeric) binding layers, with or without using mechanical fasteners. Cementitious liquids and pastes are generally not used to adhere flexible floor coverings to their respective substrates. Presently, flexible floor coverings that employ adhesives comprise non-cementitious adhesive polymers, often in combination with mechanical fasteners. In the case of carpeting and some other flooring types, various underlays such as flexible foam sheets can be and are often sandwiched between the carpet and substrate floor.
Many of the flexible floor coverings described above can also be used as wall coverings. However, the most common type of interior wall covering is paint, with wallpaper also being a very important type. The wall substrates in present use comprise stone, brick, concrete, concrete masonry blocks and wooden boards and panels as well as plaster among earlier types although modern interior wall systems are largely built using gypsum wallboards that have the joints made smooth and ready to accept one or more coats of paint, wallpaper or other type of covering. Various types of paints, varnishes and other finishes are applied as a liquid with brushes, rollers or sprayers, then dry or otherwise cure into a solid finished coating. Wallpapers are normally adhered using non-cementitious liquid adhesives that similarly dry or cure into a solid form. Wallpapers are often installed using starch-based adhesives. Vinyl peel-and-stick wallpapers are available but are less common than conventional wallpapers that require a separate adhesive layer.
For interior floors and walls, flexible coverings were and are still often used on top of either rigid or flexible coverings. For example, a bearskin can be hung on a painted wall or loosely laid on top of a mat or carpet that, in an example of further layering, has said mat or carpet installed on a stone tile floor where the stone tiles have been grouted and adhered to a wood or concrete floor substrate using a cementitious compound.
Flexible coverings are typically delivered and installed from rolls, packages of flat strips or bundles or boxes of tiles.
Paints and other types of coating compounds that are applied as a liquid and dry or cure into solid form and become permanently adhered to wall substrates are also used on floor substrates, albeit not as commonly as they are used on walls. In the case of flooring, the most common cases where floors are painted or coated using a liquid application are in commercial and industrial flooring sectors, usually on concrete or steel floor substrates. Ship floors, usually referred to as decks, are normally covered in this manner.
It is quite evident from this above description that there is often a desire to have floor or wall coverings, except in the case of paint where it is usually relatively easily recoated without needing to remove the earlier paint covering, not be permanently adhered to the respective floor or wall substrates. This is especially preferred in the case of many flexible covering applications. The desire for non-permanent adhesion is less common for rigid flooring types although there are people who would prefer to be able to change rigid floor tiles to replace damaged ones or change the style from time to time without needing to engage in difficult and costly removal and replacement procedures that usually damages or destroys the covering being removed, adhesive layer and/or substrate.
Floor and wall adhesives are normally considered to be permanent which means that they are only used once to fix a covering onto a respective substrate. The adhesive layer is destroyed and needs to be replaced when an existing covering is removed and a new covering is installed. The covering is also normally destroyed and replaced with a new one. This removal and replacement does not normally occur in the case of paint. Where paint is used as a covering, the existing paint covering simply has one or more additional layers of paint applied on top of the existing paint. This is not the usual case for other types of floor or wall coverings although does occur in some situations. For example, wallpaper can have another layer adhered overtop of an existing one but this is not considered to be the best approach. The better practice, albeit more costly and difficult, is to strip out the old wallpaper and adhesive layer then apply a fresh adhesive with the new wallpaper. Non-permanent adhesives are generally not very effective for use with carpets and other floor or wall coverings inasmuch as they tend to degrade over time and/or with repeated use.
For installations of wall-to-wall carpet, it is often preferable to glue the carpet down, especially for large area installations. For installations of vinyl tiles, as is the case for most types of tile flooring, whether flexible or rigid types, it is generally considered a requirement that the tiles must be bound to the substrate using an adhesive. Due to the large areas often involved, such adhesives need to be cost-effective on an installed cost per unit area calculation basis. Where an adhesive layer needs to be replaced, the costs are not normally considered to be prohibitive. Magnetic adhesion systems for attaching wall and floor coverings to respective wall and floor substrates have gained limited market acceptance in recent years. They tend to be rather costly as compared to traditional adhesives. However, the benefit of being able to remove, reposition and/or replace the coverings without damaging them, the substrate or the magnetically attractive layer of the substrate has been shown to be of considerable benefit.