GB2309714A

GB2309714A - Sound deadening floor construction

Info

Publication number: GB2309714A
Application number: GB9601871A
Authority: GB
Inventors: Robin Kenneth Mackenzie
Original assignee: Heriot Watt University; Edinburgh Acoustical Co Ltd
Current assignee: Heriot Watt University; Edinburgh Acoustical Co Ltd
Priority date: 1996-01-30
Filing date: 1996-01-30
Publication date: 1997-08-06
Anticipated expiration: 2016-01-30
Also published as: GB9601871D0; GB2309714B

Abstract

A floor construction has a support surface 1 on top of which is a layer 2 of polymer foam which in turn supports a substantially continuous floor 3 for treading on. The polymer foam layer 2 is a decoupling layer provided by a reconstituted multi-density polymer foam. The reconstituted multi-density foam is formed by mixing pieces of different density virgin open cell foam and subsequently compressing the mixture to form a continuous solid piece of material.

Description

SOUND DEADENING FLOOR CONSTRUCTION The present invention relates to floor constructions and in particular to floor constructions which utilise a layer of resilient polymer foam to decouple a floor for treading on from a support surface.

In floor constructions where it is required to minimise the transmission of sound through the floor it is common to provide a layer of resilient polymer foam between the upper floor surface and a lower support surface. Such 'floating floor' constructions are described for example in GB2,214,537, EP0,536,161, GB2,259,131 and W094\27000.

Typically, these constructions use low density open cell (doc) virgin foams having a density of approximately 28kg/m3 or a combination of ldoc foam panels and closed cell polymer foam panels.

A disadvantage of floor constructions incorporating ldoc foam is that they exhibit discernible movement underfoot as they are walked upon. This movement can be disconcerting and poses potential problems of fatigue along joints in tongue and groove jointed upper floor surfaces.

It is an object of the present invention to provide a floor construction which offers better load bearing potential than conventional floating floor constructions.

It is a second object of the present invention to provide a floating floor construction which offers improved sound isolation.

It is a further object of the present invention to provide a floating floor construction which provides improved stability for persons walking on the floor.

According to the present invention there is provided a floor construction comprising a substantially continuous floor for treading on, a support surface beneath the floor, and a polymer foam decoupling layer disposed between the support surface and the floor, wherein the polymer foam is a reconstituted multi-density foam.

Embodiments of the present invention exhibit a number of advantages over known floor constructions. These include reduced buckling and yield characteristics, a reduced natural frequency, higher mechanical energy absorbtion, and improved impact sound insulation.

Reconstituted multi-density foam is produced by mixing pieces of different density virgin foam and compressing (and possibly heating) the mixture to form a solid block of foam. Typically, the virgin foams used in the mixture will range in density from 10kg/m3 to 250kg/m3 with the individual pieces ranging in size from lmm3 to lcm3.

Preferably, the virgin foams used to form the multi-density foam will be of the open cell type.

In one embodiment of the present invention, the floating floor construction is a deck or platform type floor in which the support surface is a continuous surface, for example of concrete or timber boards (e.g. an existing floor). The polymer foam decoupling layer may also be continuous or may comprise foam panels or strips spaced apart from one another. In particular, where the floor for treading on is provided by a multiplicity of floor panels jointed together, the spaces between the multi-density foam panels may be aligned with the joints between the floor panels. As described in W094/27000, the gaps between the multi-density foam panels may contain strips of relatively high stiffness polymer foam, for example of the closed cell type.Alternatively, the gaps between the multi-density foam panels may be provided with strips of relatively high density multi-density foam of a second type.

In an alternative embodiment of the invention, the support surface is provided by a plurality of spaced apart battens or strips, for example timber battens or strips.

In this case, the polymer foam decoupling layer may be provided by a plurality of strips of reconstituted multidensity foam disposed between the upper surface of the battens and the opposed lower surfaces of the floor for treading on.

For a better understanding of the present invention and in order to show how the same may be carried into effect reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a sectional elevation of floor construction in accordance with an embodiment of the present invention; Figure 2 is sectional elevation of a floor construction in accordance with a second embodiment of the present invention; Figure 3 shows the results of static tests carried out on a virgin ldoc foam and on a multi-density foam; Figure 4 shows the results of dynamic tests carried out on a virgin ldoc foam and a multi-density foam; and Figure 5 shows the sound attenuating properties of a virgin ldoc foam and a multi-density foam.

There is shown in Figure 1 a floor construction having a continuous support surface 1 which may for example be formed from reinforced concrete or timber boards. Laid on top of the support surface 1 is a layer of polymer foam 2 which separates the support surface 1 from an upper floor 3. The upper floor 3 is formed from a plurality of floor panels 3a, 3b, 3c etc which are jointed together to form a continuous treading surface. The polymer foam layer 2 acts to decouple the upper floor 3 from the support surface 1 thereby reducing the levels of sound and vibration transmission through the floor construction.

The polymer foam decoupling layer 2 is provided by a multi-density polymer foam. This foam is formed by mixing pieces of virgin low density open cell foam having a range of different densities, and compressing (and possibly heating) the mixture to form a continuous solid piece of material.

Figure 2 shows a second embodiment of the present invention in which the support surface is provided by a multiplicity of timber battens 4. Provided on the upper surfaces of the timber battens 4 are respective strips of reconstituted multi-density foam 5. The upper floor 6 rests on the multi-density foam which again acts to decouple the floor from the support surface. Typically, the upper floor 6 is fixed to the foam strips 5 by an adhesive, with the strips 5 in turn being adhered to the timber battens 4.

Figure 3 illustrates the stress vs strain characteristics for virgin ldoc foam (having a density of 28kg/ç) and for a reconstituted multi-density foam (having a mean density of 80kg/m3 as supplied for example by Kay Metzeler Limited, UK, catalogue number KC5). The data was obtained using British Standard Test No. BS4443-1.

As can be seen from Figure 3, the virgin foam exhibits an almost linear relationship between stress and strain up to a particular yield stress after which there is a rapid increase in stress. For a person walking on a floor comprising a decoupling layer of virgin ldoc foam, this characteristic exhibits itself as an initial resistance to compression followed by a rapid giving in the floor.

Reconstituted multi-density foams do not behave in this way.

Figure 3 shows that for the multi-density foam there is no clearly defined yield point and the stress vs strain characteristic is much more linear. The result is a floor in which compression is more gradual and less perceptible to a person walking on the floor.

Figure 4 shows frequency vs acceleration characteristics for the same virgin idoc foam and multidensity foam obtained using British Standard No. BSEN290521. For each material, the fundamental resonant frequency (natural frequency) is taken to be that at which peak acceleration occurs. It is apparent that the resonant frequency for the multi-density foam is significantly lower for the multi-density foam than for the virgin foam, 26HZ as opposed to 38HZ. It is well understood that materials which exhibit a low fundamental resonant frequency also exhibit lower levels of force transmission than comparable materials with higher resonant frequencies. Multi-density foams therefore offer lower levels of sound and vibration transmission than virgin ldoc foams.

Figure 5 shows the impact sound insulation characteristics for virgin ldoc foam and for multi-density foam, from which it can be seen that at almost all frequencies of interest the level of impact sound insulation through the multi-density foam is higher than that through virgin foam.

Experiments carried out reveal that the properties of multi-density foam are superior to those of virgin ldoc foam, even where the density of the virgin foam is comparable to the mean density of the multi-density foam.

Whilst the properties of virgin ldoc foam tend to improve with density, the cost of high density virgin ldoc foam tends to be prohibitive.

Claims

CLAIMS:

1. A floor construction comprising a substantially continuous floor for treading on, a support surface beneath the floor, and a polymer foam decoupling layer disposed between the support surface and the floor, wherein the polymer foam is a reconstituted multi-density foam.

2. A floor construction according to claim 1, wherein the reconstituted multi-density foam is produced by mixing pieces of different density virgin foam and compressing the mixture to form a solid block of foam.

3. A floor construction according to claim 2, wherein the virgin foams used in the mixture range in density from 10kg/m3 to 250kg/m3.

4. A floor construction according to claims 2 or 3, wherein the virgin foams used to form the multi-density foam are of the open cell type.

5. A floor construction according to any one of claims 2 to 4, wherein the individual pieces range in size from lmm9 to lcm3.

6. A floor construction according to any one of the preceding claims, wherein the floor construction is a deck or platform type floor in which the support surface is a continuous surface.

7. A floor construction according to any one of the preceding claims, wherein the support surface is provided by a plurality of spaced apart battens or strips.

8. A floor construction substantially as hereinbefore described with reference to Figure 1 and Figures 3 to 5 or Figures 2 to 5 of the accompanying drawings.