GB2420355A

GB2420355A - Joist with adhered acoustic insulating material

Info

Publication number: GB2420355A
Application number: GB0523489A
Authority: GB
Inventors: Nicholas Higgins
Original assignee: ROWAN TIMBER SUPPLIES
Current assignee: ROWAN TIMBER SUPPLIES
Priority date: 2004-11-20
Filing date: 2005-11-18
Publication date: 2006-05-24
Also published as: GB0523489D0; GB0425588D0

Abstract

A joist 10 comprises a body having upper and lower surfaces 12, 14 and a layer of acoustic insulating material 18 adhered to at least one of the upper and lower surfaces. Material 18 may be an open- or closed - cell foam: the joist may be an I-joist as shown, or a C- or other section joist, comprising wood, OSB, or metal. The joist may be used in erecting a floor 22, e.g. of chipboard and a ceiling 24 of plasterboard. In another embodiment (Fig 3, not shown) there is a sub floor overlaid with battens with adhered acoustic foam overlaid with a floor; acoustic quilting may be placed between the sub floor and ceiling.

Description

1 1i4ist" 3 The present invention relates to a joist for 4 buildings.

6 Joists form the support between internal ceilings 7 and floors in buildings. Joists are elongate beams, 8 and are typically arranged in rows. Generally, the 9 floor is supported on the upper surfaces of the joists, and the ceiling of the room below is 11 supported on the lower surfaces of the joists.

13 Commonly, joists are timber beams of rectangular 14 section, but I-joists having top and bottom flanges spaced apart by a central web are also known.

17 It is very important that the flooring system does 18 not transmit a large amount of noise. This is 19 particularly important in flatted developments, where different families live directly above and 21 beneath each other, but it is also important in sole 1 Occupancy developments. Both impact noise and 2 airborne noise should be minimized.

4 Noise reduction has become a much greater concern in recent years, with stricter government legislation, 6 "Part E" legislation of the Building Regulations 7 being introduced in England and Wales. In flatted 8 developments, the part E legislation requires a 9 minimum airborne noise reduction of 45db DT + 0tr and a maximum impact Sound transmission of 62db 11 where DT is the measurement used to measure the 12 airborne Sound insulation between two rooms on site, 13 0tr is a correction factor added to take into account 14 low frequency noise and LT is the measurement used to measure the impact Sound insulation between 16 floors on site. In sole occupancy accommodation, 17 the minimum airborne noise reduction is 40db R, 18 where R is the weighted sounded reduction index.

19 The stricter noise requirements for flatted developments are particularly difficult to meet.

21 The noise requirements for sole occupancy 22 accommodation are also difficult to meet as house 23 builders are trying to minimise costs.

One way to reduce the noise to acceptable levels is 26 to include a quilt between the ceiling and the 27 floor. However, this is an expensive solution.

29 According to a first aspect of the invention there is provided a joist comprising a body having upper 31 and lower surfaces and a layer of acoustic 1 insulating material adhered to at least one of the 2 upper and lower surfaces.

4 Embodiments of the invention can be used to provide increased acoustic insulation capabilities, in both 6 high and low specification flooring systems. Some 7 embodiments can be used to support a floor which 8 comprises a single flooring portion, e.g. for use in 9 sole occupancy developments. Preferred embodiments improve the acoustic insulation sufficiently such 11 that a quilt is not necessary to achieve the minimum 12 airborne noise reduction of 40db R. Furthermore, 13 because of the improved acoustic insulation 14 properties of joists according to the invention, these joists can be made significantly less deep 16 than would otherwise be required to achieve the same 17 noise reduction using conventional joists. For 18 example, joists according to the invention may have 19 depths of as little as 195mm, and still achieve the 40db R minimum airborne noise reduction. Not only 21 are these shallower joists cheaper to produce, but 22 using shallower joists enables the overall height of 23 the building to be reduced, which provides a 24 significant cost saving. The invention is not limited to joists of any particular height.

27 Typically, the layer of acoustic insulating material 28 is adhered by a hard-fix glue or wood glue. An 29 example of a suitable adhesive is Weyroc D4 Rapid DeckTM adhesive; however, any suitable adhesive may 31 be used. Weyroc D4 Rapid DeckTM adhesive is 1 available from Egger UK, Anick Grange Road, Hexham, 2 Northumberland NE46 4JS, United Kingdom.

4 Adhering the acoustic insulating material to the body of the joist provides several advantages. The 6 acoustic insulating material can be precisely 7 Positioned on the body in fabrication, in controlled 8 in-door conditions. Attaching the acoustic 9 insulating material to the joist in fabrication, instead of on-site, saves time on-site, and is more 11 efficient, saving costs. Using adhesive bonding 12 means that additional mechanical fixing of the 13 acoustic insulating material to the joist body is 14 not essential Embodiments which do not include such additional mechanical fixings can provide 16 improved acoustical properties.

18 Preferably, the acoustic insulating material is 19 adhered to at least the upper surface of the body.

This acoustically decouples the flooring from the 21 joist if the flooring is laid on the joist.

23 Optionally, a respective layer of acoustic 24 insulating material is adhered to each of the upper and lower surfaces of the body.

27 Preferably, the acoustic insulating material 28 comprises foam, most preferably resilient low 29 resonance acoustic foam.

31 Optionally, the acoustic insulating material 32 comprises a closed cell foam. An example of a 1 suitable closed cell foam is a physically cross 2 linked polyethylene/polyolefin closed cell foam with 3 a density of around 33kg/rn3. Closed cell foams have 4 the advantage that they are stiffer and less prone to damage in a building site.

7 Alternatively, an open cell foam may be used.

8 Suitable examples include polyurethane open cell 9 foam with a density of 32kg/rn3, and reconstituted low resonance acoustic chip foam. Open cell foams 11 can provide enhanced acoustic performance.

13 Optionally, the foam has resilient, rubber-like 14 properties.

16 The invention is not limited to the use of any 17 particular foam.

19 In some embodiments, the acoustic insulating material comprises a double layer of foam, e.g. each 21 layer comprising a different type of foam.

23 Preferably, the acoustic insulating material is 24 laminated, to the body.

26 Optionally, the layer of acoustic insulating 27 material is fixed by at least one mechanical fixing 28 to the body, in addition to being adhered thereto.

29 Such embodiments may help prevent or restrict relative lateral movement of the acoustic insulating 31 material and the body, and hence, may also prevent 1 or restrict lateral movement of a floor Supported by 2 the joist.

4 Typically, the joist comprises an I-joist.

Alternatively, the joist comprises a C-shaped joist.

6 Alternatively the joist has a rectangular cross- 7 section. Alternatively the joist comprises a 8 lattice joist.

Optionally, the joist comprises a timber joist, e.g. 11 a solid timber joist or a timber I-joist.

12 Alternatively, the joist comprises metal, e.g. a 13 steel joist; optionally a lightweight galvanise 14 steel joist or a steel lattice joist. Hence, the invention is not limited to any particular type of 16 joist.

18 Optionally, the joist comprises an I-joist having 19 upper and lower flanges and an intermediate board.

Typically the intermediate board comprises Oriented 21 Strand Board (OSB) . Typically, the flanges comprise 22 solid timber flanges or laminated veneer lumber 23 flanges.

Optionally, the acoustic insulating material is 26 provided along the entire length and/or width of the 27 upper or lower surface of the body. Alternatively, 28 the acoustic insulating material may be provided in 29 intermittent (relatively short) lengths at various positions along the length and/or width of the body.

31 Hence, the acoustic insulating material does not 1 necessarily cover the entire upper or lower surface 2 of the body.

4 According to a second aspect of the invention there is provided a flooring assembly including a floor 6 and a ceiling, and a plurality of joists, at least 7 one of which is a joist according to the first 8 aspect of the invention.

Preferably, all of the joists are joists according 11 to the first aspect of the invention. Typically, 12 the floor comprises chipboard flooring. Optionally, 13 the floor comprises more than one layer, e.g. a 14 chipboard layer on top of a plasterboard layer.

Typically, the ceiling comprises gypsum wallboard.

17 Optionally, the floor comprises more than one 18 component, for example an upper flooring portion and 19 a lower flooring portion, e.g. a floating floor and a sub-deck layer.

22 Preferably, the floor is adhered to the joists.

24 Alternatively or additionally, the floor is fixed to at least one joist by at least one mechanical 26 fixing, e.g. a nail or screw. Optionally, the 27 mechanical fixing engages the floor, the acoustic 28 insulating material and the body of the joist.

Optionally, the ceiling is fixed to lower surfaces 31 of the joists.

1 Optionally, a quilt layer is provided between the 2 ceiling and the floor, although preferred 3 embodiments achieve the minimum noise reduction of 4 40db R without including a quilt. Embodiments which do include a quilt between the ceiling and the 6 floor can achieve an even greater noise reduction 7 than the minimum requiremnt 9 Embodiments of the invention provide a flooring system which achieves the minimum noise reduction of 11 40db R for sole occupancy developments, whilst 12 still being relatively cheap and having a small 13 number of components. Embodiments can be used in 14 otherwise conventional low specification flooring systems, to provide improved acoustic insulation.

17 According to a third aspect of the invention there 18 is provided a flooring assembly comprising: 19 a floor comprising an upper portion and a lower portion; 21 a ceiling; 22 a plurality of separators separating the upper 23 portion and the lower portion of the floor; and 24 a plurality of joists supporting the floor and the ceiling, at least one of which is a joist 26 according to the first aspect of the invention.

28 Therefore, embodiments of the invention also provide 29 a high specification flooring system. The use of a layer of acoustic insulating material adhered to a 31 surface of one or more joists can provide even 1 better acoustic insulation than a conventional high

2 specification flooring system.

4 Preferably, all of the joists are joists according to the first aspect of the invention.

7 Typically, the separators comprise battens, 8 Preferably, elongate wooden battens. Optionally, 9 the separators have an adhered layer of acoustic insulating material. Optionally, a quilt layer may 11 be provided between the ceiling and the floor, as a 12 further insulating layer. The quilt layer may 13 provide improved noise and thermal insulation. In 14 alternative embodiments, the quilt layer is omitted.

16 Optionally, the upper portion of the floor comprises 17 a floating floor. Typically, the upper portion of 18 the floor is made from either chipboard or 19 plasterboard or a combination of both. Typically the lower portion of the floor comprises a sub-deck 21 board, typically OSB.

23 According to a fourth aspect of the invention there 24 is provided a method of creating a flooring system, using at least one joist according to the first 26 aspect of the invention.

28 Preferably, all of the joists used are joists 29 according to the first aspect of the invention.

31 Optionally, the method includes the step of building 32 the rest of the floor around the at least one joist.

2 Optionally, the method includes the step of fixing a 3 floor to at least one joist with a mechanical fixing 4 that engages the floor, the acoustic insulating material and the body of the joist. Such fixing may 6 prevent or restrict both relative lateral movement 7 of the acoustic insulating material and the body, 8 and lateral movement of the floor itself.

According to a fifth aspect of the invention, there 11 is a provided a method of building a floor including 12 the steps of using at least one joist having an 13 attached layer of acoustic insulating material 14 adhered to at least one of its upper and lower surfaces, and building the rest of the floor around 16 the at least one joist.

18 According to a sixth aspect of the present invention 19 there is provided a method of making a joist according to the first aspect of the invention, the 21 method including the steps of: 22 applying adhesive to an upper or lower surface 23 of a joist body; and 24 adhering a layer of acoustic insulating material to that surface.

27 This method has the advantage that the layer of 28 acoustic material can be exactly dimensioned and 29 aligned on the joist body at the fabrication stage to ensure a good load distribution. In preferred 31 embodiments, the acoustic material is adhered to an 32 upper surface of the joist at the fabrication stage 1 and the adhesive can be applied to the entire area 2 of the upper surface so that the acoustic material 3 is attached to the entire surface. In alternative 4 embodiments, the acoustic material may be applied in intermittent short lengths, instead of along the 6 entire length of the joist body.

8 Embodiments of the invention will now be described, 9 by way of example only, and with reference to the following drawings, in which:- 12 Fig 1 shows an end view of an elongate I-joist 13 according to the invention; Fig 2 shows an end view of some I-joists of Fig 1 16 used in a low specification flooring system; and 18 Fig 3 shows an end view of some I-joists of Fig 1

19 used in a high specification flooring system.

21 Referring now to Fig 1, a joist in the form of an I- 22 joist 10 is shown. The I-joist 10 has a body 23 comprising an upper flange 12, a lower flange 14 and 24 an intermediate board 16 connecting the upper and lower flanges 12, 14. The I-joist 10 is elongate 26 and IS typically four to six metres in length; 27 however the invention covers embodiments of any 28 length. The I-joist 10 may be supplied in lengths 29 of up to 15 metres.

31 The flanges 12, 14 are optionally made from solid 32 timber, or alternatively from laminated veneer 1 lumber. The flanges 12, 14 are typically each at 2 least 38mm tall (the vertical direction in the Fig 1 3 view), and about 45-iQo wide (the horizontal 4 direction in the Fig 1 view) 6 The intermediate board 16 5 typically at least 7 9.5mm thick. The intermediate board 16 typically 8 comprises Oriented Strand Board (OSB), although 9 other materials may also be used.

11 None of these exemplary size measurements are 12 limiting to the invention.

14 A layer of acoustic foam 18 is adhered (e.g. laminated) on the top of the upper flange 12.

16 Optionally, the acoustic foam layer 18 may also be 17 secured by one or more screws/other mechanical 18 fixings (not shown) to the upper flange 12. This 19 could prevent or restrict relative lateral movement of the foam layer 18 and the upper flange 12, and 21 hence, prevent or restrict lateral movement of a 22 floor supported by the I-joist 10.

24 The acoustic foam layer 18 comprises an acoustic closed cell crosslinked polyolefin foam. In 26 alternative embodiments, other types of foam may be 27 used, for example, the other types described above.

29 The acoustic foam layer 18 is typically S-2Omm thick (preferably S-lOmm thick), and has the same 31 longitudinal and width dimensions as the top of the 32 flange 12, so that the foam layer covers 1 substantially the entire area of the top of the 2 flange 12. However, in alternative embodiments, the 3 acoustic foam layer 18 does not extend along the 4 entire length and/or width of the flange 12.

Optionally, a Plurality of short acoustic foam 6 layers 18 are fixed to the flange 12, with gaps in 7 between adjacent foam layers 18.

9 The total depth of the I-joist 10 (from the base of the lower flange 14 to the top of the foam layer 18) 11 is typically between l95mm and 402mm inclusive, and 12 more particularly, can be approximately l95rnin, 13 220mm, 241mm, 302mm, 356mm or 402mm. However, the 14 invention is not limited to embodiments having these depths. In alternative embodiments, the foam can be 16 replaced by any acoustic insulating material.

18 Referring now to Fig 2, I-joists 10 according to the 19 invention form part of a low specification flooring system 20. Although just three I-joists are shown, 21 typically more would typically be provided, enough 22 to span the floor/ceiling area to be supported. The 23 low specification flooring system 20 also includes a 24 floor 22 and a ceiling 24, which are supported by the upper flanges 12 and the lower flanges 14 of the 26 I-joists 10 respectively The floor 22 comprises a 27 single layer of 22mm chipboard flooring, and the 28 ceiling 24 comprises a single layer of 15mm gypsum 29 wallboard. Alternative embodiments may use other materials/other thicknesses.

1 The I-joists 10 are adhered to both the floor 22 and 2 the ceiling 24. Optionally, the I-joIsts 10 may 3 also be secured to the floor 22 and/or ceiling 24 by 4 screws or other mechanical fixings (not shown) . In the case of the floor 22, the mechanical fixings 6 could extend through the floor 22, through the 7 acoustic foam layer 18 and into the upper flange 12.

8 Such embodiments may help to prevent or restrict 9 relative lateral movement between the acoustic foam layer 18 and the upper flange 12, and relative 11 lateral movement of the floor 22 with respect to the 12 I-joists 10.

14 The I-joists 10 are arranged such that their elongate axes are parallel, with a distance of 16 approximately 600mm between the axes of neighbouring 17 I-joists. In alternative embodiments, the spacing 18 between the axes of neighbouring I-joists may be 19 300 or 400mm. However, other spacings may also be used and are included within the scope of the 21 invention.

23 Some flooring systems according to Fig 2 can provide 24 the required degree of acoustic insulation corresponding to the type E legislation for sole 26 occupancy developments (a noise reduction of 40db 27 R) with only a single flooring layer and a single 28 ceiling layer, and without including a quilt, due to 29 the inclusion of I-joists 10 with an acoustic insulating material layer.

1 Fig 3 shows a high specification flooring system 30 2 which incorporates I-joists 10. Fig 3 is not drawn 3 to scale.

Starting from the top, the flooring system 30 6 includes an upper flooring portion, which comprises 7 an 18mm chipboard layer 32 on top of a 19mm 8 plasterboard plank 34. Optionally, the upper 9 flooring portion comprises a floating floor.

11 A series of elongate wooden battens 36 are arranged 12 parallel to each other and support the plasterboard 13 layer 34. The battens 36 are typically made from 14 dressed whitewood, although other materials could also be used. The battens 36 each have a layer of 16 resilient low resonance acoustic foam 38 adhered to 17 their lower surfaces. The battens 36 may have 18 square or rectangular cross-sections.

The battens 36 are in turn supported by a lower 21 floor portion in the form of a 15mm OSB sub-deck 40.

22 Also supported on the sub-deck 40 is a 25mm layer of 23 mineral fibre 42.

Below the sub-deck 40 are I-joists 10, which support 26 the sub-deck 40. One I-joist 10 is provided 27 directly under each batten 36. The typical Spacing 28 of the I-joists 10 and the battens 36 is 29 approximately 300mm, 400mm or 600mm.

31 In alternative embodiments, the battens 36 can be 32 aligned Perpendicularly to the I-joists 10.

2 The I-joists 10 also support a ceiling on their 3 lower flanges 14. The ceiling comprises a resilient 4 bar 42, and two layers of 12.5mm plasterboard 44, 46. The ceiling layers 42, 44, 46 are adhered to 6 each other. Typically, the ceiling comprises more 7 than one resilient bar 42, which may be aligned 8 perpendicular to or parallel to the I-joists 10.

The I-joists 10 are typically screwed to the sub- 11 deck 40 and to the resilient bar 42. Hence, 12 prevention or restriction of relative lateral 13 movement may be achieved, as described above with 14 reference to the Fig 2 embodiment. Alternatively or additionally, the I-joists 10 may be adhered to the 16 sub-deck 40 and to the resilient bar 42.

18 An acoustic quilt 48 is provided on the plasterboard 19 44, typically between adjacent resilient bars 42.

The acoustic quilt 48 is a high density quilt 21 manufactured from non-combustible natural glass 22 fibres, which provide reduced noise transmission and 23 improved thermal insulation. it should be noted 24 that in a modified version of the Fig 2 embodiment, a similar quilt 48 could also be used.

27 Therefore, embodiments of the invention according to 28 Fig 3 can provide a very high specification flooring 29 system, with improved noise reduction properties compared to conventional high specification flooring 31 systems.

1 Modifications and improvements can be incorporated 2 without departing from the scope of the invention.

3 For example, all dimensions given are provided as 4 examples only, and do not limit the scope of protection.

7 In the Fig 3 embodiment, the materials used for each 8 component may be different. Also, the number of 9 components shown may vary. For example, the upper floor 32, 34 may alternatively comprise a single 11 component instead of the two layers 32, 34, and the 12 same applies to the three layers of the ceiling 42, 13 44, 46.

The mineral fibre layer 42 and the acoustic quilt 48 16 are both optional.

18 The battens 36 may be replaced by any kind of 19 separators, and they do not necessarily have any bonded layer of acoustic foam 38. If a layer of 21 acoustic foam 38 is provided, it may comprise any 22 material. In some embodiments, the acoustic foam 23 layer 38 can comprise the same material as used in 24 the acoustic insulating material which is adhered to the I-joists 10.

27 The I-joists 10 can be separated by any required 28 distance. Optionally, the floor 32, 34 comprises a 29 floating floor. Optionally, some or all of the Fig 3 components are adhered to their adjacent 31 components.

1 Although the illustrated example relates to an I- 2 joist, the invention also includes any kind of joist 3 mentioned in respect of the statement of invention, 4 and any other type of joist not mentioned. The joist can comprise metal (e.g. steel), wood, or any 6 other suitable material.

8 Any suitable adhesive can be used.

Claims

1 Claims 3 1. A joist comprising a body having upper and 4 lower surfaces

and a layer of acoustic insulating material adhered to at least one of the upper and 6 lower surfaces.

8 2. A joist as claimed in claim 1, wherein the 9 acoustic insulating material is adhered to the upper surface of the body.

12 3. A joist as claimed in claim 1 or claim 2, 13 wherein a respective layer of acoustic insulating 14 material is adhered to each of the upper and lower surfaces of the body.

17 4. A joist as claimed in any preceding claim, 18 wherein the acoustic insulating material comprises 19 foam.

21 5. A joist as claimed in claim 4, wherein the foam 22 comprises a resilient, low-resonance acoustic foam.

24 6. A joist as claimed in claim 4 or claim 5, wherein the acoustic insulating material comprises a 26 closed cell foam.

28 7. A joist as claimed in any of claims 4 to 6, 29 wherein the acoustic insulating material comprises a double layer of foam.

1 8. A joist as claimed in any preceding claim, 2 wherein the acoustic insulating material is 3 laminated to the body.

9. A joist as claimed in any preceding claim, 6 wherein the layer of acoustic insulating material is 7 fixed by at least one mechanical fixing to the body, 8 in addition to being adhered thereto.

10. A joist as claimed in any preceding claim, 11 comprising an I-joist.

13 11. A joist as claimed in any preceding claim, 14 comprising a timber joist.

16 12. A joist as claimed in any of claims 1 to 10, 17 comprising a metal joist.

19 13. A flooring assembly including a floor and a ceiling, and a plurality of joists, at least one of 21 which is a joist according to any of claims 1 to 12.

23 14. A flooring assembly as claimed in claim 13, 24 wherein all of the joists are joists according to any of claims 1 to 12.

27 15. A flooring assembly as claimed in claim 13 or 28 claim 14, wherein the floor is adhered to the 29 joists.

1 16. A flooring assembly as claimed in any of claims 2 13 to 15, wherein the floor is fixed to at least one 3 joist by at least one mechanical fixing.

17. A flooring assembly as claimed in claim 16, 6 wherein the mechanical fixing engages the floor, the 7 acoustic insulating material and the body.

9 18. A flooring assembly as claimed in any of claims 13 to 17, wherein the floor comprises an upper 11 flooring portion and a lower flooring portion.

13 19. A flooring assembly as claimed in claim 18, 14 wherein the upper flooring portion comprises a floating floor and the lower flooring portion 16 comprises a sub-deck layer.

18 20. A flooring assembly comprising: 19 a floor comprising an upper portion and a lower portion; 21 a ceiling; 22 a plurality of separators separating the upper 23 portion and the lower portion of the floor; and 24 a plurality of joists supporting the floor and the ceiling, at least one of which is a joist 26 according to any of claims 1 to 12.

28 21. A flooring assembly as claimed in claim 20, 29 wherein all of the joists are joists according to any of claims 1 to 12.

1 22. A flooring assembly as claimed in claim 20 or 2 claim 21, wherein the separators comprise wooden 3 battens.

23. A flooring assembly as claimed in any of claims 6 20 to 22, wherein the separators have an adhered 7 layer of acoustic insulating material.

9 24. A flooring assembly as claimed in any of claims 20 to 23, including a quilt layer provided between 11 the ceiling and the floor.

13 25. A flooring assembly as claimed in any of claims 14 20 to 24, wherein the upper portion of the floor comprises a floating floor and the lower portion of 16 the floor comprises a sub-deck board.

18 26. A method of creating a flooring system, using 19 at least one joist according to any of claims 1 to 12.

22 27. A method as claimed in claim 26, wherein all of 23 the joists used are joists according to any of 24 claims 1 to 12.

26 28. A method as claimed in claim 26 or claim 27, 27 including the step of building the rest of the floor 28 around the at least one joist.

29. A method as claimed in any of claims 26 to 28, 31 including the step of fixing a floor to at least one 32 joist with a mechanical fixing that engages the 1 floor, the acoustic insulating material and the body 2 of the joist.

4 30. A method of making a joist as claimed in any of claims 1 to 12, including the steps of: 6 applying adhesive to an upper or lower surface 7 of a joist body; and 8 adhering a layer of acoustic insulating 9 material to that surface.