GB2305445A

GB2305445A - Sound-proofing building walls

Info

Publication number: GB2305445A
Application number: GB9519441A
Authority: GB
Inventors: John Sidney Shute
Original assignee: DUNBRIK
Current assignee: DUNBRIK
Priority date: 1995-09-22
Filing date: 1995-09-22
Publication date: 1997-04-09
Anticipated expiration: 2015-09-22
Also published as: GB9519441D0; GB2305445B

Abstract

To improve sound absorption, a filling block (30), or other filling material, is placed in the air space between back-to-back gas fire flues formed in walls of respective dwellings such as semi-detached houses or town houses built back-to-back.

Description

Improvements Relating to Buildings This invention relates to buildings, and in particular relates to buildings of a type, such as domestic dwellings, wherein flues are created in the building walls. The flues typically will be gas fired flues leading from recesses adapted to accommodate gas fires.

The evolution of domestic dwellings in this country has lead to the creation of smaller dwellings with smaller rooms, and this has lead to the designing of sitting rooms and the like with recesses which are designed to accommodate gas fires. A gas fire needs not only a recess, but it also requires a flue which extends upwardly from the recess into a roof space and out of a chimney structure which extends through the roof.

Where dwellings are other than completely detached, it is usual for builders to build the dwellings so that the flues and recesses are located in walls of respective dwellings which are arranged back to back. Between these walls is an air space, and building regulations require that the overall sound absorbing qualities of the back to back wall arrangement should be within certain limits. When a pair of back to back walls has a cavity between the walls the walls must present a mass of 300 kg/m2. This limit is in fact the lower limit and is applicable because the air space forms a sound deadening layer and with such mass per unit area in the combined walls, it is considered that the sound deadening between back to back properties is acceptable.If the wall is made solid however with building blocks of a type typically used for back to back walls, which are also internal walls, then the mass per unit area increases considerably to 415 kg/m2.

The flue blocks referred to above which form the flue are rectangular blocks with a flue passage extending from one face to the opposite face. These blocks are formed of compressed concrete, and therefore represent as much sound absorbing mass as conventional solid blocks. The provision of flue blocks in a wall therefore of a back to back nature does not cause the wall to lie outside the regulations.

However, in the region of the recess, the recess blocks, which also are made of compressed concrete, are of channel shaped configuration, with the open side facing outwardly into the room for the receipt of a gas fire or the like.

When such recess blocks are located in a wall, the wall in the region of the recess blocks unfortunately does not need the sound deadening requirements, but heretofore this has largely gone unnoticed, because the presence of a gas fire in the recess blocks tends to have a sound deadening effect which may in effect bring the wall in that region up to regulation standard.

We have discovered however that this is not the case, and we therefore provide an improvement to overcome the unidentified disadvantage which exists in connection with existing flue systems in back to back walls.

In accordance with the present invention, a method of building wherein a flue is embodied in a wall of a back to back wall arrangement of which the walls are separated by an air space, involves providing a filling in the air space behind the recess blocks, which filling is designed and/or constructed so as to have the characteristic of bringing the sound deadening characteristic of the walls of the back to back wall arrangement up to the level to meet regulations but not to provide a solid mass which would require a greater level of regulation as related to sound deadening qualities.

The filling can be used behind the recess blocks in any of the following circumstances.

(A) Where there are recess blocks in respective walls and arranged in register back to back, (B) Where there are recess blocks in respective back to back walls, but the recess blocks of the respective walls overlap, and (C) Where there are recess blocks in respective back to back walls, but are relatively displaced without overlap.

In cases (B) and (C), the filling preferably is sufficient to improve the sound deadening qualities of the back to back walls in the region of each of the recesses, and in the case of arrangement (C), there may be separate fillings for the separate recesses.

In a preferred construction, the recess filling is a concrete block formed with a cavity which provides for the control of the sound deadening characteristic of the back to back wall arrangement in the region of the or each recess.

The said filling block may comprise a slab with a rim round three edges namely two opposite edges which will be vertical in use, and a top edge connecting the two vertical edges.

Alternatively, the block could be formed with a passage therethrough to provide the said air space.

The filling block preferably is of a similar size to the recess.

As an alternative, a single flat slab of concrete could be provided on one side with a layer of sound insulating material, or the sound insulating material may comprise for example a block of a material which is different from the concrete used for the recess blocks and different from the building material used for the adjacent wall blocks which define the wall of each of said back to back walls.

Other modifications may be made without departing from the scope of the invention, and an embodiment thereof will now be described, by way of example, with reference to the accompanying diagrammatics drawing, wherein: Fig. 1 is a sectional plan through back to back walls built according to the embodiment of the invention; Figs. 2 and 3 are enlarged views showing the recess region in front and side elevation; Figs. 4, 5 and 6 respectively are front view, side view and plan of the filling block shown in Fig. 1; and Figs. 7, 8, 9 and 10 respectively show different embodiments of the filling block.

Referring to the drawings, and firstly to Fig. 1, two back to back walls, 10 and 12 are formed for example in the back to back walls of semi-detached houses. Between the walls 10 and 12 is an air space 14, and Fig. 1 shows that each of the walls is provided with a recess 16, 18, and the recesses are arranged back to back. These recesses are suitable for receiving gas fires, and as shown in Figs. 2 and 3, each recess is made up of a number of recess blocks which are referenced 1ZM (being the block type) and the recess they create leads to a flue of which a first flue block 2GM is shown. The flue is indicated by reference 20 and 22 for the respective recesses, and it will extend up the wall and into the roof space and eventually out of the roof.

The flue blocks 1ZM are of open channel section as shown clearly in Fig. 1 so that the respective flues 16 and 18 face outwardly into the rooms in which they are located.

Reference numeral 24 in Fig. 1 indicates the conventional wall blocks which are used for building domestic building walls which are internal in nature, as walls 10 and 12 will be having regard to the back to back construction.

The arrangement thus far described has been utilised for many years, and is still utilised in the construction of new dwelling houses. It is usual to arrange the recesses 16 and 18 in register in back to back as shown but in some cases the recesses may be offset so as to be overlapped, or may be so offset, whilst still in back to back walls, that there is no overlapping whatsoever. The present invention applies to all of the various configurations discussed above.

The present invention addresses a problem which has existed for a long time and that is that building regulations require that the back to back walls be constructed so that in each square metre of wall there will be a certain mass of material which provides that there will be a certain degree of damping of sound transmission through the walls. Where a cavity back to back arrangement is present such as shown in Fig. 1, this mass per unit area must be 300 kg. This requirement is satisfied by the wall blocks 24, and also by the flue blocks 2GM, but in fact the recess blocks 1ZM arranged as shown in Fig. 1 do not meet this requirement, and there is more than the required degree of sound transmission through these recess blocks, and the present invention seeks to overcome this disadvantage. It is noted that in use the recesses will be filled for example by gas fires, and these articles in themselves tend to produce a certain amount of sound deadening but still the recess region fails to meet regulations.

In accordance with the embodiment of the present invention shown in Fig. 1, the difficulty is overcome by placing a filling block 30 between the recesses as shown. This filling block is shown also in Figs. 2 and 3, and it will be seen that it comprises a cavity 34 on side thereof, and the dimensions of that cavity are exactly equal to the dimensions of the blocks 1ZM forming the recess. The edge regions 36 of the block 30 abut the blocks 24, and the top region 38 of block 30 abuts the flue blocks 2GM.

The cavity 34 provides for sound deadening, and the filling block 30 brings the recess region up to regulation and requirement. In this connection, the filling block 30 is made of concrete and the same material as the recess blocks, and the regulation requirement would not be satisfied simply by placing a solid block 30 in the air cavity 24 because then the solid concrete construction of the recess blocks and the filling block would provide an effective means for sound transmission and there would be insufficient mass to prevent that sound transmission in this area. The filling block therefore must have a sound deadening quality which is better than a solid concrete block.

The filling block 30 is shown in more detail in Figs. 4, 5, and 6, and it would be seen to comprise a rear slab 40 having a lower edge 42, and an upper edge 44. On one face 46 of slab 40 there are flange edges 48 and 50 at the sides of the block, and a top flange edge 52. The bottom edge is left open, and the rear surface 54 is flat. This configuration prevents sound from propagating along the cavity 14 between the walls 10 and 12, and also prevents sound from propegating going upwards in the flue direction.

As mentioned herein the block is made of dense concrete and therefore requires to have cavity 34.

The filling block can be made in different configurations as shown in Figs. 7 to 10 in Fig. 7 the concrete block 60 has a central cavity 62 rather than having a cavity on one side, whereas in Fig. 8 the block 64 has narrower cavities 66 and 68 on the respective faces. In the arrangement of Fig. 9, the filling block comprises a narrow slab 70 of concrete material, to one side of which is attached a layer of sound deadening material such as foam or rock wool and referenced 72. In the arrangement of Fig. 10, the entire block is made up of a composition which gives the necessary sound deadening quality, the block being indicated by 74. In the latter case, in fact the block could be cast in place between the recesses 16 and 18.

Where the recesses are staggered to such an extent that they do not overlap, separate filling blocks may be used or a single long filling block may be adopted.

The invention provides an excellent and effective means for providing that all of the area of a pair of back to back walls meets the sound transmission regulations.

The drawings provided herein show typical sizes of the recess and filling block which apply in practice, but it is to be mentioned that the invention is not to be limited to these sizes, which are expressed in millimetres.

Claims

1. A method of building wherein back to back walls are provided with an air space therebetween for sound transmission dampening, and wherein at a location where, because of its construction, the fabric of at least one of the walls does not have sufficient sound dampening, there is provided at said locations and in the air space between the walls, filling means to bring said location up to the required said transmission dampening.

2. The method according to Claim 1, wherein the location is to the rear of a recess formed in one of the walls.

3. The method according to Claim 1 or 2, wherein the location is between two recesses which are formed back to back in the respective walls.

4. The method according to Claim 2 or 3, wherein the recess on recess is formed as a gase fire flue.

5. The method according to Claim 4, wherein the or each recess is made up of recess starter blocks which are open outwardly into a room in which a gas fire is to be located.

6. The method according to any preceding claim, wherein the filling means is a filling block which defines a sound dampening air pocket between the back to back walls.

7. The method of Claim 6, wherein the filling block comprises a flat slab having a lower edge, top edge and side edges and the cavity is defined by flanges on one side at the side edges and top edge of the slab.

8. The method of Claim 6 or 7, wherein the filing slab is of concrete.

9. The method according to any of Claims 1 to 5, wherein the filling means comprises a block of or including sound dampening material.

10. The method according to Claim 9, wherein the filling block comprises a slab of concrete to one side of which is attached a layer of sound dampening material such as foam or rock wool.

11. A filling means for use in building and in the method according to at least one of the preceding claims, substantially as hereinbefore described.

11. A method of building substantially as hereinbefore described with reference to the accompanying drawings.

12. A filling means for use in the method according to at least one of the preceding claims.

13. A filling means for use in building, substantially as hereinbefore described.

Amendments to the claims have been filed as follows CLAIMS 1. A method of building wherein back to back walls are provided with an air space therebetween for sound transmission dampening, and wherein at a specific location, because of its construction, the fabric of at least one of the walls does not have sufficient sound dampening, there is provided at said location and in the air space between the walls a filling panel to bring said location up to the sound transmission dampening of the walls remote from said location.

4. The method according to Claim 2 or 3, wherein the recess or recesses is/are formed as a gas fire flue or gas fire flues.

6. The method according to any preceding claim, wherein the filling panel defines a sound dampening air cavity between the back to back walls.

7. The method of Claim 6, wherein the filling panel comprises a flat slab having a lower edge, top edge and side edges and the cavity is defined by flanges on one side at the side edges and top edge of the slab.

8. The method of Claim 6 or 7, wherein the filling panel is of concrete.

9. The method according to Claim 8, wherein the filling panel comprises a slab of concrete to one side of which is attached a layer of sound dampening material such as foam or rock wool.

10. A method of building substantially as hereinbefore described with reference to the accompanying drawings.