In the previous blog the various options were discussed to realize the load-bearing walls. Floors are another important structural component of homes. Here too the possibilities are many.
What function do storey floors have? Floors, of course, first of all have the function of creating a separation between the different floors. In addition, the floor construction must be strong enough to withstand the loads resulting from the various use functions on a storey floor. Finally, the storey floors play an important role in stability. They often act as a stiff disk and ensure that horizontal loads can be transferred to the load-bearing elements.
Roughly, the following trends can be distinguished in the choice of a storey floor of a new storey building home:
- Wood floors
- Concrete floors
- Floors poured into work;
- Partially prefabricated floors;
- Prefabricated floors;
- Floors in steel
In the past, homes were often constructed in brick-bearing load-bearing walls that carried a wooden floor with supporting beams that transfer the weight of the wooden floors to the load-bearing brick walls. Due to the use of modern materials for the application of homes, this traditional type of floor is hardly ever used.
|· Adjustments to existing housing stock;· Occasional very small-scale homes and utility buildings;
· Storage, barns, etc.
|· Simple implementation;· Easy material selection;
· Little coordination needed on the construction site;
· Low building preparation;
· Unlimited flexibility.
|· Poor sound insulation;· Fire hazard.
Concrete floors can be subdivided into the following categories:
- Concrete floors poured on site;
- Semi-prefabricated concrete floors;
- Prefab concrete floors;
Concrete floors poured on site
Concrete floors poured on site are mainly used if the conditions at the construction site make it impossible to transport prefab components, if the complexity of the mold combined with a very limited series size is involved or if a monolithic structure is desired due to the desired mechanical behavior. The following floor types can be distinguished within this category:
- Sand floors;
- Flat plate floors;
- Tube, bulb plate, ribs and cassette floors;
- Mushroom floors;
- Beamed floors
Flooring on sand
This type of floor is mainly used if there is a fairly stable sand base that can serve as a formwork mold to use a floor that has been poured on site.
Flat sheet floors
These floors are often used as basement and storey floors. Due to the absence of bulging under the floor, the formwork is minimal, the free floor height is maximum and the pipework under the floor is not hindered by beams. These floors are only economically viable if system formwork in the form of table or tunnel formwork is used.
Tube, bulb plate, ribs and cassette floors
If the span becomes large, the required structural thickness also becomes larger. The own weight of the floor then forms a disproportionately large part of the total load. Weight can be saved by omitting concrete in the structural neutral zone in the middle of the cross-section, or at the bottom so that most of the concrete is in the pressure zone where the efficiency is highest.
This type of floor is used if only a supporting structure of columns is used. The concentrated load from the floors must be transferred to the columns by a visible or not visible column plate.
If it is no longer possible or if it is desirable to support the floor fields directly via walls or columns, a beam floor must be used. However, the application of this type of floor is labor intensive.
Semi-prefabricated concrete floors
The floorboard floor is a special form of the floor poured on site. This floor forms an intermediate form with the prefabricated part (shell) as formwork and the pressure layer deposited thereon. Because the floor is partly prefabricated, it offers many of the advantages of both types. This floor type is therefore often used in stacked housing.
As stated, wide slab floors consist of a prefabricated shell of approximately 50 mm concrete in which all the necessary reinforcement has been applied. Because the transport weight is low, this shell can have a considerable size up to a width of 3.00 m, with a length of 6.00 to 9.00 m. The slabs must be temporarily supported with short distances, after which the constructively cooperating concrete layer can be used. is applied on site. This layer of approximately 150-250 mm forms the required structural height. This creates a monolith poured floor construction similar to a flat slab floor.
A major advantage is also that much of the required horizontal piping can be poured into the floor. This means that height can be gained.
Prefab concrete floors
The prefabricated floors are often used to reduce construction time. When used for ground floor floors, there is the additional advantage that the required insulation is already integrated in the system floors.
Prefabricated concrete floors come in various types that can be traced to the following types that are used in both residential and non-residential construction:
- Rib (cassette) floors;
- Combination floors;
- Channel plate floors;
- Solid board and piping floors.
In general, the elements on the top are not finished and they are not yet connected. The finishing is done by applying a finishing layer to fill the seams and give the floor a smoother surface. This finishing layer can also serve to eliminate piping. For this purpose, a finishing layer of 50 mm is required for the removal of central heating and / or water pipes and a thickness of 100 mm for thicker pipes of connecting pipes of sewage or mechanical ventilation.
It is also necessary to deposit an extra pressure layer for some types of floors. This contributes on the one hand to the compressive strength of the structure as a whole and on the other hand to the coupling of the floor to a continuous disk, as a necessary part of the stability provision.
Rib (cassette) floors
With ribbed floors, the floor elements are provided in the longitudinal direction with two ribs on the edges of the slab. If cross ribs are also used, we are talking about ribbed cassette floors. The ribs provide the load transfer in the longitudinal direction and are suitable for taking line loads such as through walls.
Combination floors are system floors that are constructed from prefabricated concrete beams, separate insulation elements (filling elements) and a concrete layer poured in situ. Combination floors are typical ground-floor floors that are available from stock because of their insulation, because beams and filling elements are standard. With larger floor loads, the center to center distance can be reduced and with locally higher loads a double beam can be used.
Channel plate floors
Channel plates are fully prefabricated, pre-stressed floor plates which, in order to save on their own weight, have hollow channels. Due to the low mass and the bias, relatively long spans can be achieved. The plates are used in residential construction up to a span of 6 to 8 m. Due to their low mass, they are less suitable as residential floors.
Solid board and piping floors
The solid board floor has for the most part the same properties as the channel board floor, except for the hollow channels. Thanks to the solid construction, fewer long spans can be achieved, but this is more suitable as a residential separating floor in multi-storey construction due to the sound-insulating effect.
In addition, an intermediate form, the pipeline floor, has also been developed. This is an extra-thick channel plate floor with the lower part of the section being solid. This guarantees the structural strength and sound-insulating effect. The part of the channels can partly be replaced by full slots. These slots are suitable for drains and mechanical ventilation pipes.
Floors in steel
It is also possible to realize a floor construction with steel. Certainly in a steel frame it can have advantages due to its light weight and prefabrication. However, a disadvantage is the fire sensitivity. The following types can be distinguished:
- Steel sheet floors, single steel without additives;
- Steel concrete floors, where concrete and steel are combined.
Steel sheet floors
Steel sheet floors achieve a certain rigidity by applying profiling in the cross-section. The higher the profile, the greater the span can be. Due to the low weight, this plate is also suitable as a roof plate. However, due to the low weight and therefore the low sound-insulating capacity, the steel plate is again less suitable as a residential floor. When applied, a concrete layer then usually has to be applied.
Steel concrete floors
If the concrete on the concrete slab also starts to cooperate constructively, it is called steel concrete floors. The steel plate cooperates as a reinforcement of the concrete floor, the shear forces between the two materials must be absorbed by ridges in the steel plate. Floor constructions often use a bearing on the lower flange, so that the beam can also work as a peripheral cabinet.
As you can see there are many options and it depends on the project and the wishes of the customer which floor choice is the most efficient and effective. It is therefore advisable to use an architectural office. He has the expertise to advise you in this area.