WO1996018005A1

WO1996018005A1 - Acoustic insulation system

Info

Publication number: WO1996018005A1
Application number: PCT/GB1995/002872
Authority: WO
Inventors: Matthias Francis Smith
Original assignee: Matthias Francis Smith
Priority date: 1994-12-07
Filing date: 1995-12-07
Publication date: 1996-06-13
Also published as: AU4121896A; GB9424683D0

Abstract

A system for providing sound deafening in a floor construction having a plurality of generally parallel spaced apart joists (4a). The system comprises a plurality of trays (1a) having joist engagement portions (76) for engagement with pairs of spaced apart joists (4a) in side by side relation, so as to suspend the trays (1a) between the pairs of joists (4a). The trays (1a) contain a layer of sound deafening material (14) and the engagement portions (76) are provided with vibration damping means (10a) formed and arranged for substantially acoustically isolating the main body of the tray (1a) from the joists (4a). In use of the system, the sound deafening material (14) reduces airborne noise transmission and the vibration damping means (10a) reduces impact noise transmission.

Description

ACOUSTIC INSULATION SYSTEM

The present invention relates to a system for providing acoustic insulation between the floors in buildings particularly buildings having wooden joist constructions for supporting flooring and to so-called floating floors. The system is applicable to "new build" buildings, in particular timber frame buildings and to the refurbishment of flooring in existing buildings.

In providing acoustic insulation for buildings there are two distinct types of noise transmission requiring to be overcome, that of airborne noise and that of impact noise. In general local authority building control regulations set minimum levels for each though a particular problem in meeting these requirements is that a floor construction that meets the airborne noise level requirements may not meet the impact noise level requirements or vice versa.

Conventionally the impact requirement is sought to be met by providing a resilient strip (sometimes referred to as an "impact" strip e.g. 5 mm thick extruded polyethylene or 5mm polyproplyene felt) between the floor deck and the joists whilst the airborne requirement is sought to be met by providing inter alia sound boards between the joists for supporting floor deafening or pugging such as ash or a graded limestone chip such as QUIETEX (Registered Trade Mark) sound insulation material. In practice though it has been found that insufficient floor deafening is often placed between joists and/or that the resilient strip is mal-fitted or omitted resulting in a flooring installation or refurbishment which does not fully meet either or both of the airborne and impact noise requirements. Moreover conventional methods are generally time consuming and awkward to install thereby also making them more expensive in practice.

It is an object of the present invention to avoid or minimise one or more of the above disadvantages. The present invention seeks to provide a system for installing sound deafening in conventional timber-joist type floor constructions so as to enable the floors more readily and efficiently to comply with both airborne and impact noise control tests by local authority building control regulations.

The present invention provides a system for providing sound deafening in a floor construction having a plurality of generally parallel spaced apart joists, which system comprises a plurality of trays, said trays having joist engagement portions for engagement with pairs of said spaced apart joists in side by side relation, so as to suspend said trays between said pairs of joists, said trays containing a layer of sound deafening material and said engagement portions being provided with vibration damping means formed and arranged for substantially acoustically isolating the main body of the tray from said joists whereby, in use of said system, said sound deafening material reduces airborne noise transmission and said vibration damping means reduces impact noise transmission.

Thus with a system according to the present invention acoustic insulation against impact and airborne noise may be simply and readily installed between the floors in a building.

Preferably a said tray comprises a generally planar base, desirably provided with drainage aperture means, and two upstanding spaced apart generally parallel side walls formed and arranged for more or less closely fitting between the opposed side walls of said joists. Said base and said side walls of said tray may be in the form of a single discrete item though preferably said tray is a composite item comprising preferably two side walls each side wall having a joist engagement portion and inwardly extending lip projecting from the bottom portion thereof formed and arranged for supporting thereon a discrete tray base. Said base may be generally planar though preferably it is corrugated. The spacing apart of the corrugations may be varied according to the particular application. Advantageously the base is slightly convex on its upper side and concave on its underside for improved stiffness and rigidity which is desirable during building to help prevent operatives and/or their equipment falling through between joists. The amount of curvature of the base may be varied according to the particular application.

Preferably said joist engagement portions comprise laterally outwardly extending lips projecting from the top portion of said side walls and are formed and arranged for engagement with the upper horizontal surface of a said joist. Said joist engagement portions may be formed and arranged integrally with said side walls of said tray so as to suspend the tray and said sound deafening material generally equidistantly between and along said pairs of joists. Desirably said side walls are also provided with said vibration damping means so as to substantially acoustically isolate the main body of the tray from said joists. Most preferably though there is provided a joist saddle member comprising a central joist engagement portion formed and arranged for engagement with the upper or lower horizontal surface of a said joist and two spaced apart side walls depending from each side of said central portion, said side walls having at their bottom portion lips extending in opposite directions and formed and arranged for supporting one side of a said discrete tray base. Desirably the inside surfaces of said joist saddle member are provided with said vibration damping means so as to substantially acoustically isolate a tray or tray base supported thereby from said joists. Said joist saddle member may be made from extruded polyvinylchloride (PVC) or the like and supplied in any desired length or in longer lengths which may be cut to length or in longer lengths which may be cut to length for a particular application.

Thus in one respect the present invention provides a tray for use in an acoustic insulation system for flooring which tray comprises a base having two upstanding spaced apart generally parallel side walls, each wall having an outwardly extending lip, said side walls having a spacing from each other of from 200 mm to 800 mm, preferably 300 mm to 600 mm, desirably 400 mm to 450 mm.

In a further respect the present invention provides a tray system for use in an acoustic insulation system for flooring which tray system comprises a base and two joist saddle members, each of said joist saddle members being formed and arranged for saddling across respective ones of a pair of spaced apart joists in side by side relation, each said saddle member having a joist engagement portion for engagement with the upper horizontal surface of one of said pair of spaced apart joists and two spaced apart side walls depending from each side of said joist engagement portion and each said side wall having at a portion distal from said joist engagement portion, support means in the form of a lip portion for supporting a respective side of a said base between a pair of said spaced apart joists in use of the tray system.

The depth of the side walls of the tray or the saddle member will dictate how far down betweeen pair of spaced apart joists a tray will sit relative to the top or bottom of the joists as will the actual depth of the joists. Preferably though the side walls are formed and arranged so that the tray is offset relative to the centre of the joist i.e. closer to the top or the bottom of the joist depending on the application.

Said vibration damping means is preferably in the form of a layer of generally known "impact" or resilient strip.

Typical examples include 5 mm thick extruded polyethylene; 5 mm polypropylene closed cell felt; 25 mm mineral wool; and 6 mm heavy duty polyvinylchloride, conveniently with a self adhesive strip. Conveniently said vibration damping means comes in strip form with a self adhesive backing so that it may be fixed to trays on site. Alternatively said vibration damping means may have been previously attached or is integrally formed with said tray in the course of its manufacture.

Different grades of "impact" or resilient strip may be used on said side walls of said tray (or the side walls of said saddle member) and said joist engagement portion of said tray (or said saddle member) . Vibration damping means, also in the form of said generally known "impact" strip, is preferably provided on the outer face of said joist engagement portion i.e. that surface on which a floor is laid so that said floor also "floats" on the joists.

Preferably said tray has an indicator means for indicating a minimum predetermined depth of sound deafening material therein. Preferably said minimum depth of sound deafening material is in the range of from 30 mm to 100 mm, advantageously 40 to 70 mm desirably 60 mm. Suitable sound deafening material includes whinstone, graded limestone chip such as QUIETEX (RTM) or solid slabs of for example compressed fibreglass.

Preferably said tray is made from a plastics material which is generally extruded or theπno-formed. Desirably the materials used for said system provide for at least limited fire retardant performance. Polyvinylchloride (PVC) is particularly desirable because of its self-extinguishing characteristics. Polystyrene may also be used. Other suitable materials include steel, preferably galvanised.

Preferably said tray is extruded or moulded in manufacture so that there is formed into the inner surface of the side walls a bead or ridge or the like to indicate as aforesaid the minimum depth to which the tray should be filled with sound deafening material. Conveniently there may also be provided on said inner surface of said side walls means for connecting to the tray or supporting, by snap-fit connection or otherwise, cabling or conduit means or the like used for providing various services in the building in a convenient manner. Preferably there is provided on said inner surface of said side wall means for connecting cross-bracing struts thereacross.

The tray of the invention can be any desired length which may, if required, be cut to length for a particular application.

Conveniently there are provided end plates for releasable, preferably snap-fit interengagement with the ends of a said tray. Alternatively said trays may be provided in pre- determined lengths e.g. lm, 2m, 3m and provided with integrally formed end plates and/or bracing struts for containing said sound deafening material. If desired said trays may also be provided with lid means in order substantially to contain said sound deafening material within a said tray. It will be appreciated that this latter option could be used for the prefabrication of ready-filled trays off-site for use in a system according to the invention.

Preferably the side walls of said trays are slightly outwardly inclined towards their upper edges i.e. slightly wedge shaped so as to facilitate nesting thereof and thus transportation. Advantageously the side walls are slightly resilient and thereby allow trays to be push-fitted into the space between joists. This is particularly useful where the system is used in the refurbishment of existing flooring and where there has been some bending/warping/twisting of joists. Preferably there may be provided cross-bracing struts between said side walls so as to provide for increased structural rigidity of a floor installation and/or to help prevent bending, warping or twisting of joists.

Preferably said trays are also provided at the upper edge portions of the sidewalls with an inwardly extending flange formed and arranged to permit screw fixing of a floor deck to said tray of the system or to said saddle member. It will therefore be appreciated that with such an arrangement. not only is the main body of the tray acoustically isolated from the joists, but also the floor which said joists support i.e. the floor and the sound deafening are both floating.

Preferably though a said floor deck is secured by nailing or screwing to a central portion of said joist bracing struts or along a floor bearer which passes through a plurality of spaced apart bracing struts so that actual connection of the floor to the joist is indirect and substantially spaced apart thereby to improve the acoustic isolation of the flooring system.

Thus in a further aspect the present invention provides a system for providing sound deafening in a floor construction having a plurality of generally parallel spaced apart joists, which system comprises a plurality of spaced apart joist bracing struts, said struts having joist engagement portions for engagement with pairs of said spaced apart joists in side by side relation, so as to suspend said struts between said pairs of joists, said struts mounting elongate floor bearers so as to extend between said pairs of joists generally parallel thereto for supporting flooring, said engagement portions being provided with vibration damping means formed and arranged for substantially acoustically isolating the said struts and said bearers from said joists whereby, in use of said system, impact noise transmission through the floor is reduced.

In yet another further respect the present invention provides a modular or cassette flooring system having improved sound deafening characteristics which flooring system comprises a floor deck , having a plurality of spaced apart joists in side by side relatioon, mounted to the trays of a system of the present invention whereby said flooring system may be prefabricated off-site and transported to a building under construction and inserted thereinto.

Further preferred features and advantages of the present invention will appear from the following detailed description given by way of example of some preferred embodiments illustrated with reference to the accompanying drawings in which:- Fig. 1 is a perspective view of a tray for use with the sound deafening system according to the present invention in place across two joists;

Fig. 2 is a perspective view similar to Fig. 1 showing the complete sound deafening system according to the present invention;

Fig. 3 shows an end view of the embodiment shown in Figs. 1 and 2;

Fig. 4 shows a view similar to Fig. 2 of a second embodiment of the invention; Fig. 5 shows an end plate for use in jointing between trays;

Fig. 6 is a perspective view similar to that in Fig. 2 showing a third embodiment of the invention;

Fig. 7 is an end view of a tray for use in the embodiment shown in Fig. 6; and Fig. 8 is an end view of a joist saddle member for use in the embodiment of Fig. 6.

In more detail and with reference to Fig. 1 the sound deafening system according to the invention consists of a tray, generally indicated by reference number 1, having outwardly extending flanges 2 so as to suspend the tray 1 between a pair of joists 4.

The outside of the side walls 6 of the tray 1 and the underside 8 of the outwardly extending flanges 2 are provided with vibration damping means in the form of a layer of insulating resilient material 10 so as to acoustically isolate the main body of the tray 1 from the joists 4, and the tray 1 is arranged so that the side walls 6 fit closely with the side walls (7) of the joists 4.

Turning to Fig. 2 which shows the system fully installed, the base 12 of the tray is filled with sound deafening material 14 e.g. QUIETEX (R.T.M.) up to a level indicator lip 16 on the internal side wall 18 of the tray l. This lip 16 ensures that the required thickness (usually 60 mm) of sound deafening material 14 is used. The lips 16 also serves to retain in position a cover 20. The trays are also provided with end plates for providing a bracing/jointing panel between trays (see Fig. 5) .

The upper portion 22 of the internal sidewall 18 of the tray is provided with a pair of elongate grooves 24 (see also Fig. 1) for snap-fit engagement with the ends of a cross- bracing strut 26. The strut, 'T'-shaped in section, provides additional rigidity to the joists 4 and thus the flooring 28 supported thereby. The uppermost portion of the internal sidewall 18 has an inwardly extending lip 30 (see also Fig. 1) to which the flooring 28 is attached by screws 32. The flooring 28 is attached further to the top 34 of the strut 26 by screws 32.

Fig. 3 is an end view of the embodiment shown in Fig. 2 (without the strut 26) and shows in detail the edging arrangement for use with the system of the present invention. At the edge of a flooring installation the damping layer 10 is extended across past the top of the joist 4 under the flooring and is returned over the floor surface, and under a skirting board 36, surplus damping layer material being trimmed after fixing of the skirting board 36 to the ground or wall framing. The small gap 38 that exists between the joist nearest the wall 34 is simply filled with sound deafening material 14 which rests on the plasterboard and/or plywood support 40 of the ceiling 42 below.

It will be appreciated that various modifications may be made to the above described embodiments without departing from the scope of the present invention. Thus, for example, the trays may be installed from below as shown in Fig. 4 wherein there are provided two side plates 44 each provided with a backing layer of insulating material 10 for abutting against the inside face of a joist 4. The side plates 44 have a number of pre-drilled holes 46 so that the side plates 44 may be attached by screws 48 to the joists 4. The opposed inside face 49 of each side plate 44 has two parallel longitudinally extending lugs 50 which are provided with a layer of impact material 52. The tray, indicated by reference number la, has a top 54 a base 56, two side walls 58 and is filled with sound deafening material (not shown) . The outer surface of each side wall 58 of the tray la has two parallel longitudinally extending lugs 60 which co- operate by snap-fit engagement with the two parallel longitudinally extending lugs 50 on the side plates 44 when the tray la is pushed upwards between the plates so that the tray la is then supported by the side plates 44. The engagement between the pairs of lugs 50, 60 defines a sealed air gap 61 which prevents acoustic noise transmission. A ceiling 42a is screw fitted to the underside 14a of the tray la and a layer of impact material 10 is provided between the ceiling 42a and each joist 4 to prevent impact noise transmission. It will be understood that in this particular embodiment it is the ceiling 42a which is floating and not the floor 28 supported by the joists 4 which is floating as in the earlier embodiments described above and shown in Figs, l to 3.

Fig. 5 shows one of the end/jointing bracing plates 62 used for providing bracing between joists 4 and for connecting together two trays 1. The end plate 62 comprises top and bottom stiffener portions 64, 66 each generally similar to the cross-bracing strut 26 described above with reference to Fig. 2, a centre plate portion 68 provided with integrally formed stiffening cross bars 70; and two outwardly extending flanges 72 for suspending the end plate 62 across the top of two joists 4. Flanges 71 at the upper edge of the bottom stiffener 66 provide a support for the end portion of the base of a tray 1. The side walls 74 and the underside of the flanges 72 of the end/jointing plate 62 are provided with a backing layer of insulating resilient material 10 so as to acoustically isolate the plate 62 and trays 1 jointed to it from the joists 4. It will be understood that bracing plates 62 are not required at every joint between trays and in practice the bracing plates 62 may be used at only one or two points across the floor of a room as required for providing floor stiffening in a simple and convenient manner.

Fig. 6 shows a third embodiment of the invention and is generally similar to that shown in Fig. 2 and is described using like reference numbers with the suffix . added.

This third embodiment consists of a tray la. (shown by an end view in Fig. 7) having two upstanding side walls 6a and a base 12a. The tray la is supported between two spaced apart joists 4a by a saddle member 74 on each joist 4a. The saddle member 74 (see Fig. 8) is a generally inverted 'U¹- shaped channel having a central joist engagement portion 76 and two spaced apart side portions 78, 80 depending from each of the central portion 76. At the lower end of the two spaced apart side portions 78, 80 are outwardly extending lips 82 so as to suspend the tray la between the joists 4a.

The inside wall surfaces 75 of the central joist engagement portion 76 and the two spaced apart side portions 78, 80 are provided with vibration damping means in the form of a layer of insulating resilient material 10a so as to acoustically isolate the main body of the tray la supported by the saddle members 74 from the side walls 7a and upper surface 83 of the joists 4. The side walls 6a of the tray la are arranged so that they fit more or less closely with the two spaced apart side portions 78, 80, which in turn through the layer of insulating material 10a fit closely against the joist surface.

The base 12a of the tray la is full with QUITEX RTM sound deafening material 14 to a depth of approximately 60 mm.

The upper portion 22a of each of the two spaced apart side portions 78, 80 of the saddle member 74 is provided with a pair of elongate grooves 24a (see also Fig. 8) for snap-fit engagement with the ends of a cross-bracing strut 26a_* The strut 26a_» a recumbent 'E' shaped section, provides additional rigidity to the joists 4 and thus the flooring (not shown) supported thereby. An 'U' shaped slot 86 in the centre of the strut 26a supports a timber floor bearer 88 which passes along and is supported by a plurality of such struts 26a- The flooring (not shown) is screwed or nailed to this bearer 88. The bearer 88 may be glued or otherwise fixed into the support strut 26a.

As shown in Fig. 8 the outer face of the central joist engagement portion 76 is provided with a layer 84 of impact strip 10a so that the floor (not shown) floats on the joists.

Claims

1. A system for providing sound deafening in a floor construction having a plurality of generally parallel spaced apart joists (4) , which system comprises a plurality of trays (1) , said trays (1) having joist engagement portions (2) for engagement with pairs of said spaced apart joists (4) in side by side relation, so as to suspend said trays (1) between said pairs of joists (4) , said trays (l) containing a layer of sound deafening material (14) and said engagement portions (2) being provided with vibration damping means (10) formed and arranged for substantially acoustically isolating the main body of the tray (1) from said joists (4) whereby, in use of said system, said sound deafening material (14) reduces airborne noise transmission and said vibration damping means (10) reduces impact noise transmission.

2. A system as claimed in claim 1 wherein each said tray (1) comprises a base (12) and two upstanding spaced apart generally parallel side walls (6) formed and arranged for more or less closely fitting between the opposed side walls (7) of said joists (4) .

3. A system as claimed in claim 2 wherein said joist engagement portions comprise laterally outwardly extending lips (2) projecting from the top portions of said side walls (16) and are formed and arranged for engagement with the upper horizontal surface of a said joists (4) .

4. A system as claimed in claim 2 or claim 3 wherein each said tray (1) is in the form of a composite tray structure comprising a base (12) and two side walls (6) , each said side wall (6) having a joist engagement portion (2) and an inwardly extending lip (82) projecting from a bottom portion thereof for supporting thereon a said base (12) .

5. A system as claimed in claim 4 wherein are provided joist saddle members (74) each having a central portion (76) constituting a said joist engagement portion (2) formed and arranged for engagement with the upper horizontal surface of a joist (4) and two spaced apart side portions (78, 80) depending from each side of said joist engagement portion (2) , each constituting a said side wall (6) of a respective tray (l) and having lips (82) extending in opposite directions and formed and arranged for supporting one side of a said tray (1) .

6. A system as claimed in any one of claims 2 to 5 wherein said walls (6) are provided with said vibration damping means (10) .

7. A system as claimed in any one of claims 2 to 6 wherein said side walls (6) have a spacing from each other of from 200 mm to 800 mm.

8. A system as claimed in any one of claims 2 to 7 wherein a said tray (1) is provided with end plates (70) , said end plates (70) being formed and arranged with said side walls (6) for containing a said layer of sound defeaning material (14).

9. A system as claimed in any one of claims 2 to 8 wherein a said tray (1) is provided with lid means (20) formed and arranged for connection to said side walls (6) for containing a said layer of sound defeaning material (14) .

10. A system as claimed in any one of claims 2 to 9 wherein said side walls (6) have on their inner surface (18) means (24) for connecting cross-bracing struts (26) thereacross.

11. A system as claimed in any one of claims 2 to 10 wherein said base (12) has a corrugated surface.

12. A tray system for use in an acoustic insulation system for flooring which tray system comprises a base (12) and two joist saddle members (74) , each of said joist saddle members (74) being formed and arranged for saddling across respective ones of a pair of spaced apart joists (4) in side by side relation, each said saddle member (74) having a joist engagement portion (76) for engagement with the upper horizontal surface (83) of a respective one of said pair of spaced apart joists (4) and two spaced apart side walls (6a) depending from each end of said joist engagement portion (76) and each said side wall (6a) having a portion distal from said joist engagement portion support means in the form of a lip portion (82) for supporting one side of a said base (la) between a pair of said spaced apart joists (4) in use of the tray system.

13. A modular or cassette flooring system having improved sound deafening characteristics which flooring system comprises a floor deck having a plurality of spaced apart joists (4) in side by side relation, said floor deck being mounted to the trays of a system according to claim l.

14. A system for providing sound deafening in a floor construction having a plurality of generally parallel spaced apart joists (4), which system comprises a plurality of spaced apart joist bracing struts (26a) , said struts having joist engagement portions for engagement with pairs of said spaced apart joists (4) in side by side relation, so as to suspend said struts (26a) between said pairs of joists, said struts mounting elongate floor bearers (88) so as to extend between said pairs of joists generally parallel thereto, said engagement portions being provided with vibration damping means formed and arranged for substantially acoustically isolating the said struts and said bearers (88) from said joists whereby in use of said system impact noise transmission through the floor is reduced.