GB2304131A

GB2304131A - Acoustically-insulating floor

Info

Publication number: GB2304131A
Application number: GB9616785A
Authority: GB
Inventors: Bernadette Mckell
Original assignee: WALKER TIMBER Ltd
Current assignee: WALKER TIMBER Ltd
Priority date: 1995-08-12
Filing date: 1996-08-09
Publication date: 1997-03-12
Anticipated expiration: 2016-08-09
Also published as: GB9516579D0; GB2304131B; GB9616785D0

Abstract

A separating floor comprises a first, lowest, layer (1) of material, a second, middle, layer (2) of material and a third, highest, layer (3) of material. The first and second layers are vertically spaced apart to provide a lower cavity and said second and third layers are vertically spaced apart to provide a higher cavity. The second, middle, layer (4) of material is provided with a number of apertures which connect the lower and higher cavities. The construction provides improved sound insulation. Suitable materials for layer (2) include orientated strand board, fibre board, chip board, plaster board, plywood and timber. The area of the apertures is preferably about 0.7% of the area of the board. Layer (3) may comprise chipboard (10) above plants plasterboard (11), for fire-proofing purposes.

Description

SEPARATING FLOOR The present invention relates to a separating floor and especially but not exclusively to a separating floor constructed from three substantially continuous vertically spaced apart layers of material.

Separating floors are floors that are used to separate the areas of accommodation on different storeys of a building or other structure. Buildings such as tenements and blocks of flats often have several or many storeys and may therefore have several or many vertically spaced apart separating floors.

Separating floors, for example in flats, must be designed to satisfy a number of different requirements in order to function adequately and also in order to satisfy various building regulations relating to parameters such as structural loadings, sound insulation and fire resistance.

A structure comprising three layers of building material, the three layers being vertically spaced apart and connected by battens and/or joists therebetween has been found to be an effective form for separating floors. Such a structure is particularly appropriate for use in timber frame constructions, which allow considerably more rapid construction than other methods of building. It would, however, be desirable to increase the sound insulation properties of such a construction.

According to a first aspect of the present invention there is provided a separating floor comprising a first, lowest, layer of material, a second, middle, layer of material and a third, highest, layer of material said first and second layers being vertically spaced apart to provide a lower cavity and said second and third layers being vertically spaced apart to provide a higher cavity wherein said second, middle, layer of material is provided with a plurality of apertures therein, said apertures connecting said lower and higher cavities.

Preferably, structural spacing means are provided between said first and second layers and between said second and third layers.

Preferably, said structural spacing means comprise joists and/or battens.

Preferably, said structural spacing means are provided with resilient sound insulation means located between said structural spacing means and at least one adjoining layer.

Preferably, a sound insulating material, which may be mineral fibre quilting, is provided in at least one of said higher and lower cavities.

Preferably, at least one of said first, second and third layers comprises boards or sheets made from orientated strand board, fibre board, chip board, plaster board, plywood or timber.

Preferably, at least one of said first, lowest, layer and said third, highest, layer is of two-ply construction. Preferably, at least one of said two plies is of a fire resistant material.

Preferably, said apertures comprise more than 0.1% of the total surface area of the second layer of said separating floor. Progressively more preferable are percentages of at least 0.2%, 0.4% and 0.7% of the total surface area of the second layer of said separating floor. Preferably, said percentage does not exceed 7%.

Preferably, said apertures are substantially circular in cross-section.

Preferably, said apertures have a diameter of more than 2 mm and less than 200 mm.

According to a second aspect of the present invention there is provided a construction material in the form of a sheet or board for use in forming the middle, second, layer in a separating floor in accordance with the first aspect of the present invention, said construction material being provided with a plurality of apertures therein.

Preferable features of said construction material may be ascertained from the above described preferable features of a separation floor in accordance with the first aspect of the invention.

According to a third aspect of the present invention there is provided a method of constructing a separating floor comprising: providing first, second and third layers of material; arranging said layers of material such that said first, second and third layers are substantially horizontal, said first and second layers are vertically spaced apart and said second and third layers are vertically spaced apart; wherein said second layer is provided with a plurality of apertures therethrough.

Preferably, said method further includes providing one or more features as disclosed in the above passages relating to the first and or second aspects of the present invention.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Fig. 1 is a schematic vertical cross-section of a multi storey timber framed construction illustrated as having parallel floor joist construction on the right hand side, and perpendicular floor joist construction on the left hand side; Fig. 2 shows schematically the main structural components of a section of separating floor adjacent a vertical external wall wherein the floor joist construction is substantially parallel; Fig. 3 is a schematic vertical cross-section of a section of separating floor adjacent to a vertical external wall corresponding to area F012 of Fig. 1 wherein the floor joist construction is substantially perpendicular;; Fig. 4 is a schematic vertical cross-section of a section of separating floor provided on both sides of a vertical internal wall corresponding to area F013 of Fig. 1 wherein the floor joist construction is substantially perpendicular; Fig. 5 is a schematic vertical cross-section of a section of separating floor adjacent a vertical internal wall which separates said section of separating floor from a screeded concrete landing of a communal stairway, and corresponds to area F014 of Fig.

1; Fig. 6 is a schematic vertical cross-section of a section of separating floor provided on both sides of a vertical internal wall corresponding to area F016 of Fig. 1 wherein the floor joist construction is substantially parallel; Fig. 7 is a schematic vertical cross-section of a section of separating floor adjacent to a vertical external wall corresponding to area F017 of Fig. 1 wherein the floor joist construction is substantially parallel; Fig. 8 is a schematic vertical cross-section of a section of separating floor supporting a non loadbearing wall, corresponding to area F018 of Fig. 1 wherein the floor joist construction is substantially parallel; Fig. 9 is a schematic vertical cross-section of a section of separating floor supporting a non loadbearing wall, corresponding to area F019 of Fig. 1 wherein the floor joist construction is substantially perpendicular;; Fig. 10 is a schematic vertical cross-section of a section of separating floor supported by a loadbearing wall and supporting a non-loadbearing wall, corresponding to area F020 of Fig. 1, wherein the floor joist construction is substantially perpendicular; Fig. 11 is a schematic vertical cross-section of a section of separating floor adjacent a SWVP and a duct; Fig. 12 is a plan view of a sheet of material having apertures provided therein and suitable for use in the second, middle, layer of a separating floor having three spaced apart layers.

With reference to the accompanying drawings, an embodiment of a separating floor in accordance with the present invention which is suitable for use in a multi storey construction, generally designated 100, comprises a first, lowest, layer of material 1 in the form of a two-ply layer comprising a lower sheet of 12.5 mm thick plasterboard 16 and an upper sheet of 19 mm thick plank plasterboard 15. The separating floor also comprises a second, middle, layer of material 2 in the form of a layer of orientated strand board 13 having a thickness of 11 mm. The separating floor further comprises a third, highest, layer of material 3 in the form of a two-ply layer comprising a lower sheet of 19 mm thick plank plasterboard 11 and an upper layer of 18 mm thick chipboard 10. The plank plasterboard provides the floor with considerably increased fire resistance properties.

The second, middle, layer 2 is vertically spaced apart from the first, lower, level 1 by a first structural spacing means in the form of a plurality of joists 14, which in the illustrated embodiment are 47 mm wide by 195 mm or 220 mm deep depending on structural and loadbearing requirements. The third, highest, layer 3 is vertically spaced apart from the second, middle, layer by a second structural spacing means in the form of a plurality of battens 12, which in the illustrated embodiment are dynamic battens including a resilient foam section 12A for improved sound insulation. There is thus provided a lower cavity 19 between said first, lower, layer 1 and said second, middle, layer and a higher cavity 18 between said second, middle, layer 2 and said third, highest, layer 3.

The upper cavity 18 may be filled with an acoustically insulative material such as mineral fibre quilt 28 in order to increase the sound insulating properties of the separating floor.

The third, highest, layer is insulated from an adjoining wall, generally designated 90, by an acoustically insulating member in the form of a foam flanking strip 17. The third, upper, layer is therefore acoustically insulated from both the lower and middle layers of floor 1, 2 by the foam sections 12A of the dynamic battens 12 and also from the adjoining wall 90 by the foam flanking strip 17.

The second middle layer 2 of the separating floor is provided with a plurality of apertures 4 and an embodiment of a holing pattern for a board for use in the second layer 2 is shown in Fig. 12.

The provision of apertures 4 in the middle layer 2 significantly improves the sound insulating properties of the separating floor. This is because the provision of said apertures 4 provides the floor structure with one partial cavity therein rather than, in the case of a similarly structured floor with no apertures provided in the second, middle, layer, two closed cavities. A floor structure with two closed cavities is subject to the occurrence of undesirable resonances within the floor structure, leading to relatively poor sound insulation.

The constructions illustrated in Figs. 2 to 12 show different configurations of separating floors and adjoining parts of the building of Fig. 1. However, for convenience the apertures 4 are not shown in Fig.

2. These are provided in order to illustrate embodiments of the construction at various points within the building but will not be individually described.

The apertures 4 provided in the second, middle, layer of the separating floor can significantly improve the acoustic insulating properties of the floor, but other elements of the floor construction are also of great importance to the acoustic properties of the floor, and it is therefore important that the components are selected and assembled in order to maintain the required level of acoustic insulation. For example, if the floor is overloaded the isolation efficiency of the acoustic battens 12, 12A may be significantly reduced and/or flanking transmission may occur.

In the described embodiment the 19 mm plank plasterboard 11 and the 18 mm chipboard (together comprising the third, highest, layer) are glued and nailed to the battens 12. It is important that the nails do not penetrate the foam sections 12A, which have an open cell and a closed cell structure, since this would allow the transmission of vibrations between the third and second layers. The upper cavity may be used for light service runs, e.g. electric cables, in addition to housing the mineral fibre quilt 28.

Whilst the construction materials and dimensions described in reference to the above exemplifying embodiments are described specifically, the materials used and dimensions of the construction may be varied without departing from the scope of the invention. For example, the first and third layers 1, 3 need not necessarily be of two-ply construction, and various other types of structurally suitable material in the form of sheets or boards, including but not limited to fibre board, plywood and timber, could be used to form the first, second and third layers 1, 2, 3.

Similarly, various alternatives to the joists and battens, mineral fibre quilt and foam acoustic insulation could be included. Intumescent/accoustic seals 111 (see Fig. 11) may be used.

In the embodiment illustrated, by way of example, in Fig. 12 a total of sixty apertures, each having a 20 mm diameter, are provided in twelve rows of five apertures on a board measuring 2400 mm by 1200 mm. In this embodiment the total aperture area is about 0.7% of the area of the board. In experiment an aperture area of about 0.7% was found to provide better sound insulation than smaller percentages. Percentages slightly greater than 0.7% do not lead to a loss of performance but it is desirable not to have too great a percentage area of aperture since weakening of the material may occur.

The provision of apertures in the second layer 2 of the separating floor may, however, be varied to a great degree and various numbers, sizes, shapes and distributions of apertures may be used. Circular apertures are easy to provide and providing the apertures in one or more regular arrays and particularly in one or more generally rectangular arrays is convenient and effective.

The described embodiments of the present invention thus provide a convenient and economical way of increasing the sound insulation properties of separating floors.

Furthermore, the provision of suitably distributed apertures having an area equivalent to a small percentage of the second layer, in the second layer of the separating floor does not significantly affect the structural strength of the material forming that layer.

An additional benefit provided is therefore that during construction of a building the second layer may be used as a safe working platform for site operatives with the apertures providing drainage for water and snow.

Modifications and improvements may be incorporated without departing from the scope of the invention, and elements described could be replaced by mechanical equivalents thereof.

Claims

1. A separating floor comprising a first, lowest, layer of material, a second, middle, layer of material and a third, highest, layer of material said first and second layers being vertically spaced apart to provide a lower cavity and said second and third layers being vertically spaced apart to provide a higher cavity wherein said second, middle, layer of material is provided with a plurality of apertures therein, said apertures connecting said lower and higher cavities.

2. A separating floor as claimed in Claim 2 wherein structural spacing means are provided between said first and second layers and between said second and third layers.

3. A separating floor as claimed in Claim 2 wherein said structural spacing means comprise joists and/or battens.

4. A separating floor as claimed in either of Claims 2 or 3 wherein said structural spacing means are provided with resilient sound insulation means located between said structural spacing means and at least one adjoining layer.

5. A separating floor as claimed in any preceding claim wherein a sound insulating material, which may be mineral fibre quilting, is provided in at least one of said higher and lower cavities.

6. A separating floor as claimed in any preceding claim wherein at least one of said first, second and third layers comprises boards or sheets made from orientated strand board, fibre board, chip board, plaster board, plywood or timber.

7. A separating floor as claimed in any preceding claim wherein at least one of said first, lowest, layer and said third, highest, layer is of at least two-ply construction.

8. A separating floor as claimed in Claim 7 wherein at least one of said at least two plies is of a fire resistant material.

9. A separating floor as claimed in any preceding claim wherein said apertures comprise more than 0.1% of the total surface area of the second layer of said separating floor.

10. A separating floor as claimed in Claim 9 wherein said apertures comprise more than 0.2% of the total surface area of the second layer of said separating floor.

11. A separating floor as claimed in Claim 10 wherein said apertures comprise more than 0.4% of the total surface area of the second layer of said separating floor.

12. A separating floor as claimed in Claim 11 wherein said apertures comprise more than 0.7% of the total surface area of the second layer of said separating floor.

13. A separating floor as claimed in any preceding claim wherein said apertures comprise not more than 7% of the total surface area of the second layer of said separating floor.

14. A separating floor as claimed in any preceding claim wherein said apertures are substantially circular in cross-section.

15. A separating floor as claimed in Claim 14 wherein said apertures have a diameter of more than 2 mm and less than 200 mm.

16. A construction material in the form of a sheet or board for use in forming the middle, second, layer in a separating floor as claimed in any one of Claims 1 to 15, said construction material being provided with a plurality of apertures therein.

17. A construction material as claimed in Claim 16 wherein said material is made from orientated strand board, fibre board, chip board, plaster board, plywood or timber.

18. A construction material as claimed in either of Claims 16 or 17 wherein said apertures comprise more than 0.1% of the total surface area of said construction material.

19. A construction material as claimed in Claim 18 wherein said apertures comprise more than 0.2% of the total surface area of said construction material.

20. A construction material as claimed in Claim 19 wherein said apertures comprise more than 0.4% of the total surface area of said construction material.

21. A construction material as claimed in Claim 20 wherein said apertures comprise more than 0.7% of the total surface area of said construction material.

22. A construction material as claimed in any of Claims 16 to 21 wherein said apertures comprise not more than 7% of the total surface area of said construction material.

23. A construction material as claimed in any of Claims 16 to 22 wherein said apertures are substantially circular in cross-section.

24. A construction material as claimed in Claim 23 wherein said apertures have a diameter of more than 2 mm and less than 200 mm.

25. A method of constructing a separating floor comprising: providing first, second and third layers of material; arranging said layers of material such that said first, second and third layers are substantially horizontal, said first and second layers are vertically spaced apart and said second and third layers are vertically spaced apart; wherein said second layer is provided with a plurality of apertures therathrough.

26. A method of constructing a separating floor as claimed in Claim 25, wherein said method comprises constructing a seperating floor as claimed in any one of Claims 1 to 15.

27. A method of constructing a separating floor as claimed in Claim 25, wherein said method comprises use of a construction material as claimed in any one of Claims 16 to 24.

28. A seperating floor substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

29. A construction material substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

30. A method of constructing a seperating floor substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings.