All information on this page is copied material from Gulvfakta, which is a technical reference material, Source: Gulvfakta

1.1.0.1 Floor structure - terminology

Floor coverings, which make up the finished floor surface, are the top independent layer of the floor. It can be, for example, carpet , linoleum , rubber , vinyl , cork, laminate or parquet boards . Varnish or other surface treatment is not considered an independent coating.

Subfloors lie below the floor covering, but above the load-bearing structure. The subfloor must form a continuous surface, so that it can, for example, be used as a work floor and a base for a thin coating. It can be, for example, a floating floor, a slab floor on joists or a screed of concrete.
Note that thin layers of insulation, cork crumb board etc. is referred to as an intermediate layer and is not considered a subfloor.

The load-bearing structure consists of layers whose primary function is to absorb and transfer loads, for example concrete decks and wooden beam layers.

Fig. 1. Floor structure - terminology

Floor construction - definitions

Floors can be divided into two main types according to their constructive structure, namely:

Load-bearing floors, which include:
• Straw floors (wooden floors laid on joists)
• Wooden floors on wooden beams

Non-load-bearing floors, which include:
• Floating floors
• Glued floors
• Nailed floors
• Seamless floors
• Loosely laid floor coverings

Carrying yellow

Load-bearing floors are understood to mean floors that rest on a linear support of joists or beams. The load on the floor is transferred through boards or slabs to the underlying joists or beams, see figure 2.

Fig. 2. Load-bearing floor (straw floor)

Non-load-bearing floors

Non-load-bearing floors are understood to mean floors where the floor covering is supported in the full floor surface by a load-bearing substrate, e.g. a sub-floor made of concrete or wooden boards, see figure 3.

Fig. 3. Non-bearing floor

Floating floors

A floating floor is a floor where the floor surface can move freely in relation to the supporting substrate. This is achieved by inserting an elastic intermediate layer between the floor surface and the load-bearing substrate, so that there is certainty that the floor surface can move freely. With a floating floor, the floor surface is thus neither nailed nor glued to the substrate. The intermediate layer can be made of materials that contribute to improving thermal insulation and acoustic properties. When you choose a floating floor, it is important that the surface is level, as otherwise the load on the floor itself will be unevenly distributed, which can cause the floor to bend or crack.

Fig. 4. Floating floor

Glued floors

Glued floors are laid in a firm connection with a load-bearing, flat and stable substrate and are supported over the entire surface. The substrate can, for example, consist of a concrete or lightweight concrete deck or a floating subfloor, e.g. of glued together wooden boards.

Fig. 5. Glued/nailed floor

Nailed floors

Nailed floors are laid in firm connection with a load-bearing, flat and stable subfloor and are supported in full. The substrate can, for example, consist of a concrete or lightweight concrete deck or a floating subfloor, e.g. of glued together wooden boards.

Seamless floors

Jointless floors are laid on a load-bearing, level and stable surface and are supported in full. Usually the substrate is concrete.

Loosely laid floor coverings

Loosely laid floor coverings are laid on a load-bearing, flat and stable surface and supported in full. The substrate can, for example, consist of a concrete or lightweight concrete deck or an existing wooden floor .

1.1.0.2 What must be included when choosing a floor?

When choosing a floor, a number of different conditions must be taken into account:
• Technology (necessary usage characteristics)
• Price (total economy, i.e. both capital costs and future operating costs, e.g. costs for maintenance and cleaning)
• Aesthetics (appearance)
• Execution method (nuisance, time consumption)
• Environmental conditions (influence of indoor climate and surroundings, use of resources
See also the chapter on technology and quality.

For practical and economic reasons, it will usually be necessary to limit the required properties. The properties that are selected must therefore be the most important - the key properties - for the floor. Checklists have been prepared for the various types of floor covering to help with the selection among the many properties. When choosing or planning, the checklists can be reviewed with the client. This ensures that all significant factors have been considered. Note that it is the necessary requirements for properties that need to be determined. If higher demands are made than necessary, it will almost inevitably lead to higher prices at the same time.

1.1.0.3 Price - overall economy

As a rule, the price has a large influence when choosing a floor. In order to ensure the client the best return, total economy should be prioritized more than low acquisition price, for example constructions and materials with a long life and low maintenance costs should be weighted more than low acquisition price.

In order to assess the total economy, information is required on:

• Lifespan of the floor

As a rule, it is the lifespan of the floor covering in particular that is at issue. As good an estimate as possible should be given, e.g. based on information from life tables or supplier information combined with knowledge of the influence of the intended use, including use intensity and load. This may also include estimates of replacement intervals. Life expectancy tables can be obtained, for example, from Insurance and Pension or the Construction Development Council.

• Floor maintenance costs

including costs for surface treatment, cleaning and any expected minor repairs. Expenses for cleaning can be obtained by involving cleaning expertise, e.g. independent advisers or cleaning companies. Note, Choosing a floor September 2005 What must be included when choosing a floor?
2.5 that if cleaning is carried out using a method which deviates from that prescribed, it may cause damage to the floor covering, including a reduced lifespan.

• The expected price development.

An estimate must be made of the price development that is expected for the maintenance work in relation to the general price development throughout the life of the floor.

• The real interest rate

An estimate of the interest rate adjusted for inflation must be made.

On the Gulvbranchen website you can find a model for calculating the total economy for different types of flooring. The calculation model follows the principles from i.a. GBC although in some areas it is simplified and in other areas it is far too detailed. The model operates with a time horizon of 50 years and includes costs for installation, cleaning and maintenance as well as replacement and disposal/renewal. Cleaning processes and prices have been obtained from an external consultancy firm. The calculation model uses data about the lifespan of the various coatings, defined by the time that, according to experience, elapses from a coating being installed until it is replaced (the replacement does NOT necessarily occur due to failure of the coating, the replacement occurs more often due to changed requirements/desires for surfaces, colors and patterns, etc.). The model and accompanying instructions can be downloaded here .

The aesthetics of the floor

Aesthetics cannot be treated objectively but must always be considered when choosing a floor.
The assessment can include, for example, architectural expression, colour, texture, light reflection and pattern.

Method of execution

In many cases, in connection with the choice of floor construction, consideration must be given to which execution method can/must be used. This is because the execution method is decisive for how long the flooring work takes and how much inconvenience it causes. Among other things, it must be considered whether it is acceptable that the construction of the floor structure adds building moisture, requires special safety equipment or requires long curing times.

Environmental impacts

The materials used for the floor must not cause indoor climate problems, e.g. in the form of off-gassing of harmful or health-damaging substances. The materials must also not, during production, use or disposal, give rise to an increased risk of damage to the environment, e.g. pollution. Finally, the materials must not lead to unnecessary consumption of non-renewable resources. When assessing problems of this kind , the LCA concept is usually used, i.e. assessment of the product throughout its life cycle. Reference is made to the specialist literature, which can be found, for example, through the Danish Environmental Protection Agency. Many properties of a floor depend on the floor covering and the other properties are determined in particular by an interaction between the floor covering and the substrate used. It will therefore often be natural to choose the floor covering first and then design the substrate, so that other requirements for the overall construction are met.

It is not possible to compare technical properties of floor coverings "across" material types. The choice between the types must therefore be made on the basis of what the designer and/or the client considers to be the advantages and disadvantages of the different material types. Elastic floor coverings, textile floor coverings and laminate floors are classified according to a European classification system, which determines different areas of use. The classification is described in EN standards, which are specific for each floor covering type. Materials declared for use in one of these classes meet certain more specified properties, which depend on the type of coating. See, for example, checklist 1, which applies to linoleum.

It will often be appropriate to use a checklist in connection with choosing a floor covering. This ensures a systematic review of all significant conditions and properties of the floor in question. Separate proposals have been prepared for checklists for the elastic floor coverings, which are dealt with in Floor Facts. The suggestions can be found in the sections on the individual types of floor covering. In general, the checklists are divided into two parts.
The first part contains the properties covered by the EN classification for the type of floor covering in question. The EN classification is made with classes corresponding to use in housing, business and industry respectively. If a floor covering is chosen from a class which corresponds to the current application, one therefore knows in advance that the floor covering possesses the most important utility properties for this application. The properties appear in the checklist, and the values for classified products are marked with "color". It is therefore only necessary to set requirements for these properties if a higher property value than specified is desired.
The second part of the checklists contains properties that are not covered by the EN classification. The properties in this part of the checklist are used especially if there are special conditions to take into account, for example requirements for suitability as a conductive floor covering or suitability for use in connection with underfloor heating. For the properties in this part, you are directed to determine the property values that are necessary yourself. For each property, there are suggestions for requirement levels that can be used depending on the expected use.
Selection of property values
The property values for the individual properties are chosen independently of each other. For a current use, there may for example be a need to make high demands on certain properties, which means that you have to choose values on the right side of the chart. For others, on the other hand, there may be low or no requirements at all, and for these characteristics, characteristics can be selected from the left side of the chart. High demands on the properties are therefore only made when there is a real need for it. An example of how to alternately select property values "right", "left" and "center" is shown here on the page. The selected property values can possibly be connected so that a so-called requirements profile emerges, i.e. a property-by-property profile shows what is required of the floor covering. The ideal floor covering for a given purpose must have properties that, recorded as a profile, are similar to the requirement profile.

For linoleum, a requirements profile can look, for example, as shown in the following example, where the properties are selected on the basis of the checklists found in the review of the individual types of covering, e.g. elastic floor coverings.

1.1.0.4 Use of checklists in elections

Example of requirement profile for linoleum flooring

For a commercial building, linoleum flooring must be used as flooring in the corridors.
A 2.5 mm thick coating is chosen, which is EN-classified. This ensures the marked values for thickness, residual impression under static load, color fastness, flexibility and stability against moisture.

Impact is expected from office chair wheels, heavy, rolling industrial wheels and furniture legs, which is why it is marked that the coating must be able to withstand these impacts.
In addition, a coating that is not affected by cigarette embers is desired.
Since there are no special requirements for slip resistance, the lowest value is chosen.
A floor covering that does not charge static electricity during use is desired.
Underfloor heating must not be used.
Since the floor covering is to be used in escape route areas, select yes next to fire-suitable class Dfl-s.1 (class G floor covering).
The coating must not be used as a diverting floor covering.
The best possible sound conditions are desired, which is why it is marked that the floor covering must be able to contribute to an improvement in footstep sound.

1.1.0.5 Examples of checklists

The checklists shown (1 and 2) apply to linoleum. For each characteristic, select on the right of the form if there are large wishes/requirements, in the middle for medium wishes/requirements and on the left for small or no requirements. For economic reasons, no greater demands should be made than necessary for technical, aesthetic or other reasons.

Checklist 1 shows the properties included in the EN classification of linoleum floors. Classification of linoleum for use in homes, business and industry is based on thickness. The classes can be further divided into moderate, normal, high (and very high). Other properties comply with the marked values for EN-classified products. The specified values are minimum values.

Checklist 2. Supplementary properties that may need to be specified, e.g. due to special effects on the floor during the current use

1.1.0.6 Value Analysis

When choosing, you are faced with questions such as:
• What is more important: price, appearance or utility?
• How much, if any, must one pay more for a property to have a higher value?
• What do you do if it is not possible to find a product with the right property profile?
• How can the environment be taken into account, and what can/will you pay for it?

Questions of this type cannot be answered in general, but require a more in-depth analysis. There is a tool for this use in the form of value analysis. Briefly, the various factors: technique, price, workmanship, aesthetics and environment are each given their own weight, depending on how important they are to the client. This makes it possible, for example, to find the value of a higher technical quality, or a cheap offer which, on the other hand, does not meet all the requirements. Reference is also made to "Value analysis for tenders in turnkey contracts", B. Kold Larsen and M. Høgsted, Teknisk Forlag 1976.

How to choose a floor?

Useful solutions can be found at:
• To compare wishes and requirements for necessary properties of the floor covering with the properties of the solutions offered.
• To choose one of the usable floor coverings and design the substrate so that the remaining requirements for the overall floor construction are met.

Important properties for floor substrates

In order for the overall floor structure to function as desired, there must be cooperation between the floor covering and its substrate/subfloor and also with the surroundings, e.g. the load-bearing structure, underlying terrain or surrounding walls. It is therefore necessary for the substrate to have a number of properties, which partly depend on the current floor covering and partly on building physical requirements for the entire floor construction. The required properties are therefore not the same for all floor substrates. In the following, some of the properties of floor substrates which can be particularly important are briefly discussed:

Carrying capacity

The subfloor must be able to transfer the loads that can be expected in the intended use, without damage or deformation occurring.

Strength and stiffness/elasticity

The substrate for the floor covering must be able to withstand the static and dynamic loads, e.g. from payloads, furniture, people and rolling traffic, which must normally be expected to occur in the intended use.
For reasons of walking comfort, a certain flexibility (elasticity) may be desirable, while on the other hand, excessive deformations must not occur due to normal loads during use.

Flatness

The substrate for the floor covering must be so flat that the floor can achieve the desired flatness. For thin floor coverings and non-load-bearing wooden floors, this means that the substrate must be able to be laid out with the same flatness as desired for the finished floor.

Moisture barrier effect

In order to reduce the risk of damage due to moisture transport from below, e.g. due to building moisture, it may be necessary to provide the floor substrate with a moisture barrier.

Acoustic properties

The substrate must have such sound technical properties that it can help reduce the transmission of airborne sound and footstep sound

Heat resistance

Floor materials to be used in connection with underfloor heating systems must be able to withstand the temperatures that can be expected to occur in the current construction.

Heat insulating effect

The subfloor must contribute to the thermal insulation of the deck construction.

Stability against moisture

The floor must not suffer harmful deformations due to moisture effects from normal use.

Height leveling

The subfloor must be able to accommodate minor height differences in the underlying supporting structure.

Life

The floor substrate must retain its properties to a satisfactory extent over a long period of time exposed to normal degradation factors, e.g. moisture or physical stresses from use.