GB2301552A

GB2301552A - Acoustic material and method of use

Info

Publication number: GB2301552A
Application number: GB9510969A
Authority: GB
Inventors: Keith Anderson
Original assignee: Instafibre Ltd
Current assignee: Instafibre Ltd
Priority date: 1995-05-31
Filing date: 1995-05-31
Publication date: 1996-12-11
Anticipated expiration: 2015-05-31
Also published as: GB9510969D0; GB2301552B

Abstract

An acoustic material (20) for use in soundproofing or modifying sound comprises a relatively massive layer (24) bonded to a flexible, impact absorbing layer (26), the relatively massive layer having at least one rectilinear groove (28) formed therein. A structure comprising two or more intersecting surfaces, such as a flight of stairs, may be soundproofed by locating a groove portion of the acoustic material adjacent the intersection of the surfaces, bending the acoustic material around the structure so that the acoustic material conforms to the shape of the surfaces, and securing the acoustic material to the structure on either side of the intersection. Sealant (52) may be injected into the or each groove of the grooved portion.

Description

ACOUSTIC MATERIAL AND METHOD OF USE The present invention relates to an acoustic material for use in soundproofing or modifying sound and to a method of using the material in such a way as to soundproof a structure. The acoustic material and method find particular application in the soundproofing of a structure comprising two or more intersecting surfaces, such as, for example the structure defined by respective treads and risers of a flight of stairs. It is important to note however, that the acoustic material and method are not limited to such an application.

In the past the use of materials to soundproof or modify the sound within a building structure has typically been limited to planar surfaces having an area in excess of a predetermined value. Such surfaces might for example comprise the floor, walls or ceiling of a room. Planar surfaces having an area below the predetermined value have not in the past been considered to warrant the extra time and expense involved in soundproofing.

One exception to this general rule have been the treads of a flight of stairs. It has long been recognised that the frequent ascending and descending of a flight of stairs is the source of a large amount of noise within a building structure. In an attempt to combat this it has been known for acoustic material to be cut to fit each of the treads. This has however, proved relatively unsuccessful in that not only does this not provide very effective soundproofing but it also has an adverse effect on the dimensional integrity of the stairs since the height of each step is effectively increased by the thickness of the acoustic material. One way of overcoming this deficiency has been to also secure a layer of the same acoustic material to the risers associated with each of the treads.This restores the dimensional integrity of the stairs but at an additional cost in terms of the extra time and expense involved in fitting the acoustic material. Furthermore, it has been found that even by securing separate sheets of acoustic material to each of the treads and risers it is still not possible to attain the desired degree of soundproofing and it is thought that this is because the sheets of acoustic material are not capable of adequately covering the nosing defined at the intersection of a tread with its associated riser.

According to a first aspect of the present invention there is provided an acoustic material for use in soundproofing or modifying sound comprising a relatively massive layer bonded to a flexible, impact absorbing layer, the relatively massive layer having at least one rectilinear groove formed therein. In this way a continuous expanse of the acoustic material may be bent around a structure defining an included angle, such as that defined by a tread and its associated riser, so that the acoustic material covers both the tread and the riser and extends around the associated nosing.

Advantageously, the relatively massive layer may be provided with a plurality of mutually parallel, rectilinear grooves, Advantageously, the or each groove may be of substantially v-shaped cross-section. In particular, the or each groove may be defined by mutually inclined confronting surfaces which are inclined with respect to each other at an angle of between 300 and 900.

Advantageously, the or each groove may extend to a depth equivalent to the thickness of the relatively massive layer so that in the region of the or each groove the relatively massive layer is completely cut away.

Advantageously, the relatively massive layer may be provided with a plurality of mutually parallel, rectilinear grooves, the grooves being formed in such a way as to define two or more groups of grooves, each group of grooves comprising a plurality of grooves spaced a comparatively short distance apart and each group of grooves being spaced from each neighbouring group by a comparatively large distance. In this way the acoustic material may be specifically adapted for use in soundproofing a flight of stairs. In particular, the distance between neighbouring groups of grooves may be between 0.lm and 0.4m.

Advantageously the flexible, impact absorbing layer may comprise a fibrous layer. Alternatively the flexible impact absorbing layer may comprise either an open or A closed cell foam.

According to a second aspect of the present invention there is provided a method of soundproofing a structure comprising two or more intersecting surfaces, the method comprising the steps of providing a grooved acoustic material, locating a grooved portion of the acoustic material adjacent the intersection of the surfaces, bending the acoustic material around the structure so that the acoustic material conforms to the shape of said surfaces, and securing the acoustic material to the structure on either side of said intersection.

Advantageously, the method may comprise the additional step of injecting a sealant into the or each groove of the grooved portion. Preferably the sealant may be injected into the grooved portion prior to the acoustic material being bent so as to conform to the shape of the surfaces.

According to a third aspect of the present invention there is provided a flight of stairs comprising one or more steps and in which each step comprises a respective tread and riser and defines a respective nosing, the flight of stairs being covered with an acoustic material comprising a relatively massive layer bonded to a flexible impact absorbing layer and covered in such a way that a continuous expanse of the acoustic material covers both the tread and riser of at least one of the steps and extends around the associated nosing.

Advantageously, at least that portion of the acoustic material which extends around the nosing may be provided with one or more grooves formed in the relatively massive layer.

Advantageously, a sealant may be provided between the step and the acoustic material in the region of the nosing.

An embodiment of the present invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a perspective view of one step within a flight of stars which has been covered with an acoustic material in such a way that a continuous expanse of the acoustic material covers both the tread and riser and extends around the associated nosing; Figure 2 is an enlarged cross-sectional view of the nosing of Figure 1; Figure 3 is an underneath plan view of the acoustic material prior to it being used to cover the step of Figure 1; Figure 4 is a schematic view of a first stage in the covering of the step with the acoustic material; Figure 5 is a schematic view of a second stage in the covering of the step with the acoustic material; Figure 6 is a schematic view of a third stage in the covering of the step with the acoustic material; and Figure 7 is a schematic view of a fourth stage in the covering of the step with the acoustic material.

Referring to Figure 1 there is shown a representative step 10 within a flight of stairs, the step comprising a tread 12 and a riser 14. As is conventional, the riser 14 extends in a plane perpendicular to that defined by the tread 12 and abuts the tread close to one end to define a nosing 16. As can be seen in more detail in Figure 2, the nosing 16 is comprised of that portion of the tread 12 which projects beyond the plane defined by the riser 14 and, as is conventional, is provided with a rounded end surface 18. The flight of stairs, and hence the tread 12 and riser 14, may be constructed of wood or any other convenient building material.

Turning once more to Figure 1, the step 10 is shown as being covered by a single continuous expanse of acoustic materia 20 which overlies both the tread 12 and the riser 14 and extends around the associated nosing 16. The acoustic material 20 is held in place by means of a plurality of fasteners 22, in this case countersunk screws. Obviously, if the flight of stairs were constructed of a building material other than wood, the acoustic material 20 might need to be held in place by some alternative fastening means.

In order to be effective in preventing the transmission of sours, acoustic materials need to be relatively massive. In addition, in order to prevent the transmission of impact noise, acoustic materials preferably also include a crushable component which is capable of absorbing impact energy. One such material which combines both these attributes may be formed by bonding the impact absorbing fibre that is sold under the trade mark VITALUX by Portways of Sedgley Road, East Tipton, West Midlands, DY4 7UY, United Kingdom with the relatively massive sound barrier material sold under the trade mark REVAC by Wardle Storeys plc of Durbar Mill, Hereford Road, Blackburn, Lancashire BB1 3JU, United Kingdom.

Composite acoustic materials of the type described have been used in the past for soundproofing or modifying sound. However, because of the requirement to be relatively massive, they also tend to be relatively inflexible and certainly incapable of being bent through 900 in order for a single sheet to overlie both the tread and riser of a step. In order to overcome this deficiency a plurality of grooves 28 are formed in the relatively massive sound barrier 24.

As can be seen from Figure 3, the grooves 28 are preferably rectilinear in nature and extend parallel to each other in a mutually spaced relationship.

Preferably the grooves 28 are of v-shaped crosssection and are spaced between 0.005m and 0.05m apart.

Although the grooves 28 reduce the mass of the acoustic material within that particular region, they considerably increase the flexibility of the material enabling it to be bent around corners and so conform to the shape of an underlying structure. In principal therefore the grooves may be of any desired spacing, the more closely spaced they are the more flexible will be the acoustic material. There will however be a trade off in any particular application since it will also be desirable for the acoustic material to incorporate the maximum possible mass.

The use of the grooved acoustic material to soundproof one step within a flight of wooden stairs is shown in Figures 4-7. Referring first to Figure 4, the acoustic material 20 is cut to size so as to be capable of overlying both the tread 12 and riser 14 of the step 10. The acoustic material 20 is then offered up to the step 10 with the fibrous layer 26 outermost in such a way as to locate the grooves 28 adjacent the nosing 16. The acoustic material 20 is then secured to the riser 14 by means of a first set of screws 34, these screws being located in a region of the riser remote from the tread 12. A further set of screws 36 are driven through the acoustic material 20 and into the riser 14 close to the tread 12 to retain the acoustic material in close proximity to an undersurface 30 of the nosing 16.Before the acoustic material 20 is wrapped around the nosing 16, a sealant 32 having both soundproofing and adhesive properties is injected into the grooves 28. The acoustic material 20 is then bent around the nosing 16 and secured in place by a third set of screws 38 which pass through the acoustic material and into the tread 12 close the riser 14. Finally, a fourth set of screws 40 are used to further secure the acoustic material 20 and pass through the acoustic material and into the tread 12 at a location remote from the nosing 16.

As can perhaps best be seen in Figure 2, the sealant 32 not only causes the acoustic material 20 to adhere to the surfaces of the nosing 16 but also has the effect of filling the voids that might otherwise exist between the acoustic material and the step 10 and between the pairs of confronting surfaces making up the grooves 28, each of which may subtend a different angle depending upon the relative location of the groove with respect to the nosing 16. By removing the possibility of voids between the acoustic material 20 and the step 10, the sealant 32 serves to enhance the soundproof properties of the covered step.

In addition, the sealant 32 also adds mass and serves to minimise any soundproof properties that are lost as a result of the reduction in mass of the acoustic material 20 in the region of the grooves 28.

By covering the step 10 with the acoustic material in such a way that the fibrous layer 26 is outermost, the fibrous layer is able to absorb the impact energy transmitted to the step as someone walks up the flight of stairs thereby minimizing the proportion of the impact energy that is converted into sound. Furthermore because of the yielding nature of the fibrous layer 26, the heads of the screws 34, 36, 38 and 40 are fully received within the layer and do not project. This means that when someone walks up the flight of stairs, their foot does not come into contact with the screws which might otherwise constitute a rigid medium for the transmission of the impact energy and so enable a larger proportion of the impact energy to be converted into sound.

Although the acoustic material has been described as comprising a fibrous layer 26, it will be apparent that any flexible, impact absorbing may be used. In particular the impact absorbing material may comprise an open or closed cell foam.

Although the present invention has been described in relation to the covering of a single step 10, it will be apparent to those skilled in the art that a single continuous expanse of the grooved acoustic material 20 may be used to cover any number of steps or indeed may be used in the soundproofing of any structure comprising two or more intersecting surfaces such as a floor and wall or wall and ceiling.

However, in order to specifically adapt the acoustic material for use in the soundproofing of flights of stairs, the grooves 28 may be formed in such a way as to define a plurality of groups of grooves, each group of grooves comprising a plurality of grooves spaced a comparatively short distance apart and each group of grooves being spaced from each neighbouring group by a comparatively large distance. Preferably the distance between neighbouring groups of grooves may be between 0.ism and 0.4m.

Although the grooves 28 have been described as simply being of substantially v-shaped cross-section, it will be apparent that in such an arrangement the grooves may be defined by confronting surfaces which are inclined with the respect of each other at an angle of between 30 and 900. In another embodiment however, the grooves 28 may be of some other crosssection including both u-shaped, in which the confronting surfaces merge with an arcuate bottom surface, and square shaped, in which the confronting surfaces extend parallel to each other and at right angles to the bottom surface.

In order to adjust the flexillity of the acoustic material the grooves 28 may be made to a predetermined depth. In one embodiment the grooves 28 may extend to a depth equivalent to the thickness of the relatively massive sound barrIer 24 so that in the region of the grooves only the fibrous layer 26 is left.

It will be apparent to those skilled in the art that although the acoustic materia has been described as covering an otherwise bear step, the acoustic material may, if required, be use in conjunction with additional soundproofing or decorating materials.

This is in part due to the fact that the acoustic material of the present invention is capable of maintaining the dimensional integrity of the underlying structure which, particularly in the case of a flight of stairs, represents an important safety feature.

Claims

1. An acoustic material for use in soundproofing or modifying sound comprising a relatively massive layer bonded to a flexible, impact absorbing layer, the relatively massive layer having at least one rectilinear groove formed therein.

2. An acoustic material in accordance with claim 1, wherein the relatively massive layer is provided with a plurality of mutually parallel, rectilinear grooves.

3. An acoustic material in accordance with claim 1, or claim 2 wherein the or each groove is of substantially v-shaped cross-section.

4. An acoustic material in accordance with any preceding claim, wherein the or each groove is defined by mutually inclined confronting surfaces, said surfaces being inclined with the respect to each other at an angle of between 300 and 900.

5. An acoustic material in accordance with any preceding claim, wherein the or each groove extends to a depth equivalent to the thickness of the relatively massive layer.

6. An acoustic material in accordance with any preceding claim, wherein the relatively massive layer is provided with a plurality of mutually parallel, rectilinear grooves, the grooves being formed in such a way as to define two or more groups of grooves, each group of grooves comprising a plurality of grooves spaced a comparatively short distance apart and each group of grooves being spaced from each neighbouring group by a comparatively large distance.

7. An acoustic material in accordance with claim 6, wherein the distance between neighbouring groups of grooves is between 0.lem and 0.4m.

8. An acoustic material in accordance with any preceding claim wherein the flexible, impact absorbing layer comprises a fibrous layer.

9. A method of soundproofing a structure comprising two or more intersecting surfaces, the method comprising the steps of providing a grooved acoustic material, locating a grooved portion of the acoustic material adjacent the intersection of the surfaces, bending the acoustic material around the structure so that the acoustic material conforms to the shape of said surfaces and securing the acoustic material to the structure on either side of the said intersection.

10. A method in accordance with claim 9 and comprising the additional step of injecting a sealant into the or each groove of the grooved portion.

11. A method in accordance with claim 10, wherein the sealant is injected into the grooved portion prior to the acoustic material being bent so as to conform to the shape of the surfaces.

12. A flight of stairs comprising one or more steps and in which each step comprises a respective tread and riser and defines a respective nosing, the flight of stairs being covered with an acoustic material comprising a relatively massive layer bonded to a flexible, impact absorbing layer and covered in such a way that a continuous expanse of the acoustic material covers both the tread and riser of at least one of the steps and extends around the associated nosing.

13. A flight of stairs in accordance with claim 12, wherein at least that portion of the acoustic material which extends around the nosing is provided with one or more grooves formed in the relatively massive layer.

14. A flight of stairs in accordance with claim 12 or claim 13, wherein a sealant is provided between the step and the acoustic material in the region of the nosing.

15. An acoustic material substantially as herein described with reference to the accompanying drawings.

16. A method of soundproofing a structure substantially as herein described with reference to the accompanying drawings.

17. A covered flight of stairs substantially as herein described with reference to the accompanying drawings.