EP1680560A1 - Method of construction a prefab building - Google Patents

Abstract

The invention relates to method of constructing a prefab building having a first floor, load-bearing walls and a second floor, supported by load-bearing walls. The invention is characterised in that - the first floor is placed level, - at least two walls are placed on the first floor, wherein between the thus placed walls and the floor there is a lower joint having a width of maximally 20 mm, and - the second floor is as ceiling supported by the at least two walls, wherein between the at least two thus placed and load-bearing walls and the floor there is an upper joint having a width of maximally 20 mm wherein the first and the second joint are filled with a jointing material, and wherein the first floor, the at least two load-bearing walls, the joints, and the second floor are dimensioned such that the second floor is level.

Description

Method of constructing a prefab building

The present invention relates to a method of constructing a prefab building having a first floor, load-hearing walls and a second floor, wherein walls are placed with their bottom sides on the first floor, and the second floor is placed as ceiling on the top sides of the walls, that are placed on the first floor, which walls thus form walls that support the second floor. Such, a method is generally known. After a first floor has been placed, adjusting means such as adjusting blocks or adjusting pla-tes are provided at two positions where a wall is to be erected. The height of the adjusting means is chosen such that the±r top side is level, whereafter the wall is placed on the adjusting means. Between the bottom side of the wall and the top side of the first floor there is a joint, which is filled with cement. Usually the first floor receives a finish in order to ensure that the top surface, is horizontal (level) . Level is defined in accordance with the NEN standard 2886 applicable in the Netherlands (enclosure B, Table 8), that is to say the supported end of a horizontal component (more specifically a floor) may be maximally 8 mm higher or maximally 8 mm lower than an opposite supported end. The object of the present invention is to provide a method by which it is possible to build more quickly and more efficiently. To this end the method according to the invention is characterised in that the first floor is placed level, in the absence of adjusting means between the bottom side of a wall and the first floor, at least two walls are placed on the first floor, wherein between the bottom sides of the thus placed walls and the top side of the floor there is a lower joint which, after placing the wall, has a width of maximally 20 mm, and - in the absence of adjusting means between the top side of a wall and the bottom side of the second floor, the second floor rests as ceiling on the at least two walls, wherein between the top side of the at least two thus placed and load-bearing walls and the bottom side of the floor there is an upper joint which, after placing the second floor, has a width of maximally 20 mm wherein the first and the second joint are filled with a jointing material, and wherein the first floor, the at least two load-bearing walls, the joints, and the second floor are dimensioned such that the second floor is level. Starting from a floor that is level, thus allows the construction of a storey to be realised with the second floor being level and preferably also having the desired height. The amount of time saved in this way is considerable, with a favourable effect on the building costs. Also, it is no longer necessary to provide a finish to the top side of a floor, in particular of the first and/or second floor, especially if this floor is manufactured so as to be smooth already. When in the present application reference is made to a floor, this encompasses a floor constructed of separate elements. Usually one element spans the whole distance between two walls, wherein at least two connecting floor elements are provided in the longitudinal direction. It is obvious that if it is desirable to avoid providing a finish to the floor, said floor elements need to have at least substantially the same thickness, whereby the discrepancy in thickness is preferably less than 1 mm. Where mention is made in the present application of a ceiling, this merely means the bottom side of the floors that are placed on the walls. This term does not take into account whether, for example, a lowered ceiling is provided. When in connection with the present application the term level is mentioned, this means level as defined by the NEN standard 2886 referred to above, so that according to the present invention, when constructing several storeys (i.e. involving 3 or more horizontal components that may be considered as floor or ceil- ing) using the method according to the present invention, the applicable dimensional tolerance lies between the top and the bottom horizontal component. In the present application the term "dimensional tolerance" as defined by NEN 2881, means the difference between the upper limiting dimension (largest al- lowable dimension) and the bottom limiting dimension (smallest allowable dimension) . The maximum dimensional tolerance is equal to half the dimensional tolerance. A very important embodiment is characterised in that a jointing material in the form of a plastic-elastic material strip is used as the jointing material for the lower joint and the upper joint. Such a strip can be applied very conveniently and quickly to the place where a wall is to be erected. The strip may be provided with an adhesive layer on one or both sides. It is also very advantageous to incorporate the strip during the manufacture of the floor or the wall. Usually the floors and walls will be made of concrete, in which case the strips can be embedded. The term plastic-elastic means that the strip can be impressed, so as to compensate for any unevenness of the joint. It is important that when a wall is being placed ort a floor (or a floor on a wall) , the strip is essentially a non-fluid material. It is then instantaneously capable of fulfilling a supporting, pressure-distributing function. A second function of the jointing material is the sealing of the joint . This very advantageous embodiment of the present invention does not altogether exclude the use of a fluid sealing means, because this may be used, for example, to fill gaps between strips of jointing material. However, at least 50% and preferably at least 70% of the forces are transmitted via the strips to an underlying construction element, such as a floor. The thickness of the strip (after all the components to be placed on and above the strip have been positioned) is up to 20 mm, but in practice it is preferably between 2 and 10 mm, in particular 3 to 7 mm, e.g. 4 mm. Advantageously, the strip-like elastic material for the lower and upper joint is chosen independently from rubber,, plastic, and felt. Such materials may contain additives such as cork. According to an alternative embodiment, the walls and. floors are in direct contact with each other. In such a case it is advantageous to use as jointing material for the upper and lower joint a jointing material that is chosen independently from cement and glue . In contrast with the known method, the joint width is very small, usually less than 5 mm. If the jointing material is applied before a construction component such as a wall, only very little of the fluid jointing material is able to run away. This limits the risk of contact noise if there are adjacent buildings. To avoid these problems it is therefore, in contrast with the usual practice, not necessary to take measures such as providing a foam piece between two walls that have to be placed close together. A preferred embodiment is characterised in that the width of at least one of the upper and the lower joint is maximally 8 mm and preferably less than 5 mm. Such a limited joint width contributes to a stable construction of the building. The maximum dimensional tolerance in the height of the walls is preferably 3 mm. This makes it easier to construct even a building having several storeys within the above mentioned NEN 2886 standard, as will be revealed below, without the necessity of interim adjustment. In the event of more than one building of the same type being built next to each other, such as terraced houses, there is the guarantee that corresponding floors of storeys of adjacent buildings are placed within the applicable standards at the same height. The term "corresponding floors" in the present specification is understood to mean floors of the same storey. When in the present invention a dimension is given for a component, the target dimension, a maximum dimensional tolerance of x mm signifies that the range of allowable components is the target dimension plus or minus x mm. As already briefly mentioned several times in the foregoing, an important application of the method according to the invention is the construction of a prefab building having at least two storeys. The method of constructing such a prefab building is preferably characterised in that in the absence of adjusting means second walls are placed on the second floor, which sec- ond walls, in the absence of adjusting means between the bottom side of a second wall and the second floor, are placed on the second floor, wherein between the bottom sides of the thus placed second walls and the top side of the second floor there is a lower joint that after placing the second wall, has a width of maximally 20 mm, and in the absence of adjusting means between the top side of the second wall and the bottom side of the third floor a third floor is supported as ceiling by the at least two second walls, wherein between the top side of the at least two thus placed and load-bearing second walls and the bottom side of the third floor there is an upper joint, which after placing the third floor has a width of maximally 20 mm, wherein the joints of this storey are filled with a jointing material, and wherein the at least two load-bearing second walls, the joints of this storey, and the third floor are dimensioned such that the third floor is level. Obviously it is possible to place still more storeys. Such placing falls within the scope of the invention . Since this will be clear even to a person not skilled in trie art, this will for the sake of preserving the simplicity of the specification, not be further entered into. The maximum dimensional tolerance for the thickness of the second floor is 2 mm. In this way discrepancies regarding the thickness of floors will barely if at all contribute to discrepancies in height between corresponding floors of adjacent buildings. A preferred embodiment is characterised in that two components chosen from the first floor, the first wall, the second floor, and the second wall, are connected by means of a technique chosen from i) welding and ii) providing a bolt connection. In this way an extremely sturdy construction can be guaranteed. In order to place the first floor level it is preferred for the foundation to be made level. In this way the quick construction of the building can be commenced as soon as the components (walls, floors, etc) are delivered. The desired dimensional precision in the ve tical direction is chosen such that the load-bearing walls and the second floors are dimensioned such that the difference in height between second floors of a particular storey is maximally 16 mm. The present invention will now be elucidated with reference to the drawing, in which Fig. 1 shows a detail of two walls of two adjacent buildings constructed by a method according to the prior art; Fig. 2 shows a detail of two walls of two adjacent buildings constructed by a method according to the invention; and Figs. 3a-c depict variations of floor-supported walls, with floors resting on the walls. Fig. 1 shows two adjacent load-bearing walls 1, 1' of two buildings, such as a semi-detached house. Between the walls 1, 1' there is a cavity 10 which, among other things, has a sound-insulating function. First walls 2, 2' rest on a first floor or first floors, respectively. These are not shown, but the manner in which the first walls 2, 2' rest on the first floor (s) will nevertheless become clear from the description following below. On the respective first walls 2, 2' rest respective second floors 3, 3'. Between the first walls 2, 2' and the second floors 3, 3' there are joints 4, 4', which are filled with a strip of felt 5, 5'. To place the second walls 6, 6', the walls 6, 6^! are adjusted with the aid of two stacks of adjusting plates (not shown) . It is ensured that the top sides of said two stacks are level, whereafter the two walls 6, 6' are placed. The joints 7, 7' between the bottom side of the walls 6, 6' and the top side of the second floors 3, 3' are filled with mortar 8, 8'. The joints 7, 7' have a width of 15-30 mm. When the mortar 8, 8' sets, forces are transferred to the foundation (not shown) of the buildings. Additionally, the first walls 2, 2' are placed on the first floo (s) in a corresponding manner. The second floors 3, 3' are made level by applying a finishing floor 9, 9' . During construction it is important to avoid fluid mortar 8, 8' from the joints 7, 7' finding its way into the gap 10. Because if there is a connection between the load-bearing walls 1, 1' (which includes one via adjacent floors 3, 3') sound is easily transmitted from one building to the other, which is undesirable. In practice therefore a separating material 11, for example in the form of elastic synthetic foam, is applied between the walls 1, 1'. Although the above-described known method of prefab construction was a considerable improvement with respect to the speed with which a house can be built, the object of the invention is to further improve this, which will be explained by way of Fig. 2, wherein identical reference numerals obviously relate to the same components as described above. In accordance with the invention, the floor thickness (at least on that surface of the floor where it rest on the walls or on which the walls are placed) and the height of the wall are dimensioned such that a floor placed on the walls (or in the case of several storeys, each floor) is level in accordance with the standards. This may also cancel the necessity of a finishing floor, although the present invention does not exclude the application of a finishing floor. The method ac- cording to the invention opts for a greatly reduced width of the joints 7, 7', i.e. 20 mm or less, preferably less than 12 mm. These joints 7, 7' are preferably filled with a strip of jointing material 12, 12'. This strip 12, 12' is preferably an elongated strip, extending over the entire bottom side of the walls 6, 6'. Prior to placing the second walls 6, 6', the strip may be laid on the second floors 3, 3", or may be stuck to the bottom side of the two walls 6, 6' (for example as a single-sided or double-sided adhesive strip) . It is also conceivable, that the strip of jointing material 12, 12' is em- bedded during the manufacture of the second floors 3, 3' or preferably the walls 6, 6'. Instead of a single strip, it is also possible to use short pieces of strips. Although in the foregoing the present invention is set forth with respect to the placing of second floor 3, 3' and second walls 6, 6', it will be obvious to the person skilled in the art that there is no essential difference with respect to the placing of another floor or other walls. It is conceivable to use walls 6a, 6b of different heights, wherein the local thickness of at least one of the floors 3, 13, compensates for the difference of the height of the wall, such that the top surface of the floor 3 that rests on the walls 6a, 6b, is still horizontal. This is illustrated in Figs. 3a-c. The use of strips of jointing material 5a, 5b (or 12a, 12b) of different thicknesses (Fig. 3a) may compen- sate for possible discrepancies. For the sake of simplicity and in order to be able to build quickly it is, however, preferred for the components to be manufactured with the greatest precision possible, so that it is only necessary to level on one single occasion (the foundation or a first floor) . Fig. 3b shows the possibility of providing a horizontal component, in this case a second floor 3, with a local thickening 14. Obviously it is also possible to apply a recess 15 (Fig. 3c) (Note: for the sake of simplicity, the jointing materials are not shown in Figs. 3b and 3c) . However, in practice it will be preferred to manufacture the components, in particular the walls 6a and 6b, with the greatest precision possible since this will render them interchangeable, which simplifies the logistics. The dimensioning of the joints depends on the joint- ing material selected and the weight to be placed above the joints. A person skilled in the art will be able to choose a suitable thickness for the jointing material, either by calculation or by simple experimentation.

Claims

1. A method of constructing a prefab building having a first floor, load-bearing walls and a second floor, wherein walls are placed with their bottom sides on the first floor, and - the second floor is placed as ceiling on the top sides of the walls that are placed on the first floor, which walls thus form walls that support the second floor characterised in that the first floor is placed level, - in the absence of adjusting means between the bottom side of a wall and the first floor, at least two walls are placed on the first floor, wherein between the bottom sides of the thus placed walls and the top side of the floor there is a lower joint which, after placing the wall, has a width of maximally 20 mm, and in the absence of adjusting means between the top side of a wall and the bottom side of the second floor, the second floor rests as ceiling on the at least two walls, wherein between the top side of the at least two thus placed and load-bearing walls and the bottom side of the floor there is an upper joint which, after placing the second floor, has a width of maximally 20 mm wherein the first and the second joint are filled with a jointing material, and wherein the first floor, the at least two load-bearing walls, the joints, and the second floor are dimensioned such that the second floor is level.

2. A method according to claim 1, characterised in that a jointing material in the form of a plastic-elastic material strip is used as the jointing material for the lower joint and the upper joint.

3. A method according to claim 2, characterised in that the strip-like elastic material for the lower and upper joint is chosen independently from rubber, plastic, and felt.

4. A method according to one of the preceding claims, characterised in that as jointing material for the upper and lower joint a jointing material is used that is chosen independently from cement and glue .

5. A method according to one of the preceding claims, characterised in that the width of at least one of the upper and the lower joint is maximally 8 mm and preferably less than 5 mm.

6. A method according to one of the preceding claims, characterised in that the maximum dimensional tolerance in the height of the walls is 3 mm.

7. A method according to one of the preceding claims, wherein the prefab building has at least two storeys, char- acterised in that in the absence of adjusting means second walls are placed on the second floor, on which second floor in the absence of adjusting means between the bottom side of a second wall and the second floor, the second walls are placed, wherein between the bottom sides of the thus placed second walls and the top side of the second floor there is a lower joint that after placing the second wall, has a width of maximally 20 mm, and in the absence of adjusting means between the top side of the second wall and the bottom side of the third floor a third floor is supported as ceiling by the at least two second walls, wherein between the top side of the at least two thus placed and load-bearing second walls and the bottom side of the third floor there is an upper joint, which after placing the third floor has a width of maximally 20 mm, wherein the joints of this storey are filled with a jointing material, and wherein the at least two load-bearing second walls, the joints of this storey, and the third floor are dimensioned such that the third floor is level.

8. A method according to claim 6, characterised in that the maximum dimensional tolerance for the thickness of the second floor is 2 mm.

9. A method according to one of the preceding claims, characterised in that two components chosen from the first floor, the first wall, the second floor, and the second wall, are connected by means of a technique chosen from i) welding and ii) providing a bolt connection.

10. A method according to one of the preceding claims, characterised in that to place the first floor level the foun- dation is made to be level.

11. A method of mass-producing prefab buildings, characterised in that the load-bearing walls and the second floors are dimensioned such that the difference in height between second floors of a particular storey is maximally 16 mm.