RESISTANCE TO THE TRANSMISSION OF SOUND · PDF fileH1.1 This Part sets out the required standards for Regulations 19 to 21. ... Example: 215 mm brick, lightweight plaster, 75 mm coursing;

RESISTANCE TO THE TRANSMISSION OF SOUNDH

2H

ContentsINTRODUCTION

REGULATIONS 19, 20 & 21Resistance to transmission of sound

THE STANDARDSH1 Application of Part H H1.1-H1.4H2 Walls and floors to resist sound transmission

Airborne sound H2.1Impact sound H2.2-H2.3

PROVISIONS DEEMED TO SATISFY THE STANDARDS(H2.1) -(H2.3) Airborne sound and impact sound

ASTERISKSThroughout the Technical Standards an asterisk against a standard denotes that a provision deemed to satisfy the standardor some aspect of the standard is specified at the end of the relevant Part.

ITALICSThroughout the Technical Standards a term in italics is a defined term. The definition is listed in Part A, General.

H

3H Amdt: December 1999

4H

H


Introduction1 The intention of this Part is to protect occupants of adwelling from excessive noise transmitted from other partsof a building as this can damage health, particularly when itrecurs over a period of time. It does not apply to a whollydetached dwelling nor does it deal with external sources suchas road traffic or aircraft noise.

2 The requirements therefore apply to walls and floorsseparating a dwelling from other parts of the same buildingin different occupation and from other adjoining buildings.External walls are controlled only to the extent necessary toreduce flanking transmission around the ends of separatingwalls and separating floors. They also apply to balconies androofs which are accessible, other than for maintenance,where they are above a dwelling.

3 In addition it is envisaged that other ways of satisfyingthe regulations could be acceptable. For example; if an iden-tical block of dwellings has been built elsewhere, tested, andbeen shown to meet the performance standards, a buildingwarrant can be given on that evidence. Care is necessary toensure that results are equally applicable since, for example,a construction giving acceptable results in a stepped or stag-gered situation may not perform adequately in a straightterrace block of dwellings.

4 It should be understood that meeting the requirements ofthis Part will not guarantee freedom from the transmission ofdisturbing noise. The intention is to achieve reasonable stan-dards of sound insulation by common, economically viable,forms of construction. It is important to bear in mind thatstandards of workmanship are as important as constructionaldetails as air paths, bridging, or incorrectly placed resilientlayers can destroy the effectiveness of measures used.

H

6HAmdt: December 1999

Regulations 19, 20 & 21Resistance to transmission of sound

19 1. Subject to paragraph (2), every wall whichseparates a dwelling from another buildingand, in the case of a dwelling forming part ofa building, every wall and floor which sepa-rates the dwelling from another part of thebuilding shall provide adequate resistance totransmission of airborne sound.

2. Paragraph (1) shall not apply to a wallbetween a dwelling and any area which isopen to the external air.

20 1. Every floor separating a dwelling from anyother part of a building above the dwellingshall provide adequate resistance to transmis-sion of sound caused by impact.

2. Roofs or walkways which are situated directlyabove a dwelling and to which there is accessother than for maintenance purposes shallprovide adequate resistance to transmission ofsound caused by impact.

21 Regulations 19 and 20 shall not be subject tospecification in a notice served under section 11of the Act.

H


H1.1 – H2.3

The standardsH1 Application of Part H

H1.1 This Part sets out the required standards for Regulations 19 to 21.

H1.2 The standards apply to a dwelling other than a wholly detached dwelling.

H1.3 The standards are for separating elements (walls and floors) in a new dwelling, in a dwelling created byconversion, and in a dwelling where the building warrant covers a change of use of an element invokinga more onerous requirement e.g. in a rehabilitated flat where an existing internal wall becomes a separating wall.

H1.4 The term dwelling includes any part of a building, being a part intended for occupation as a separatedwelling, irrespective of the purpose group of the rest of the building. The elements separating such adwelling from the rest of the building must comply. Roofs or walkways to which there is access forpurposes other than for maintenance of the building, which lie directly above a dwelling, must alsocomply. Walls separating a dwelling from a common access corridor or stair, or waste chute, must alsoprovide adequate sound insulation.

H2 Walls and floors to resist sound transmission

AIRBORNE SOUND

H2.1* A wall or floor separating a dwelling from any part of a building must provide adequate resistance toairborne sound.

IMPACT SOUND

H2.2* A floor separating a dwelling from any part of a building above the dwelling must provide adequateresistance to impact sound.

H2.3* A roof or walkway over a dwelling which is accessible for any purpose other than maintenance mustprovide adequate resistance to impact sound.

8H

Provisions deemed to satisfy the standards

AIRBORNE SOUND AND IMPACT SOUND

(H2.1, The requirements of H2.1 for airborne sound and H2.2 and H2.3 for impact sound will be met whereH2.2, walls, floors and roofs -H2.3)

a. are constructed in accordance with the specified constructions given in points 1 to 17;or

b. achieve the standards given in point 18 when tested in accordance with points 19 to 29.

Specified constructions

1 The requirements for sound insulation will be met where walls and floors are constructed as specifiedbelow (but note that the diagrams do not show all the structural bracing that may be required).

2 The thicknesses, masses, and other dimensions specified are the minimum required unless otherwisestated; greater figures are therefore permissible. Timber sizes quoted are the minimum actual sizesrequired.

3 Where a mass is specified for a wall it is expressed in kg/m2 of wall face area. For a floor the mass isexpressed in kg/m2 on plan.

4 To calculate the mass of a leaf of masonry the formulae in point 5 must be used. Densities of bricks orblocks (at 3% moisture content) may be taken from a current BBA Certificate or from the manufac-turer’s literature, in which case the local authority may ask for confirmation e.g. that the measurementwas done by an accredited test house. Note that the quoted density of bricks or blocks is normally theapparent density, i.e. the weight divided by the volume including perforations, voids or frogs. This isthe density appropriate to the formulae. For co-ordinating course heights other than those given inpoint 5 use the formula for the nearest height. Include any finish of plaster, render or dry lining incalculating the mass unless otherwise stated.

H


(H2.1), (H2.3)

5 To calculate the mass of a masonry leaf use the following formulae.

Co-ordinating height of Formulae to be usedmasonry course (mm)

M-NP( –––– - 380)

75 M = T (0.79D + 380) + NP or D = T–––––––––––––

0.79

M-NP( –––– - 255)

100 M = T (0.86D + 255) + NP or D = T–––––––––––––

0.86

M-NP( –––– - 145)

150 M = T (0.92D + 145) + NP or D = T–––––––––––––

0.92

M-NP( –––– - 125)

200 M = T (0.93D + 125) + NP or D = T–––––––––––––

0.93

Where M = Mass of 1m2 of leaf in kg/m2

T = Thickness of masonry in metres i.e unplastered thickness)D = Density of masonry units in kg/m3 (at 3 % moisture content)N = Number of finished facesP = Mass of 1m2 of wall finish in kg/m2 (see below)

Mass of plaster (assumed thickness 13 mm)Cement Render = 29 kg/m2

Gypsum = 17 kg/m2

Lightweight = 10 kg/m2

Plasterboard = 10 kg/m2

6 In point 5 a mortar joint of 10 mm and a dry, set mortar density of 1800 kg/m3 are assumed.Values within 10% of these figures are acceptable.

7 For in-situ concrete or screeds calculate the mass by multiplying the density (kg/m3) by the thickness(in metres). For slabs or composite floor bases divide the total mass of the element (kg) by the planarea of the element (m2).

Conditions on the use of specified constructions

8 In any separating wall being built to meet the specified construction standard, the following conditionsmust be met -

a. no opening is permitted except a doorway between a dwelling and a stairway or passage wherethe doorway is protected by a fire door satisfying Part D;

b. no service pipes or ducts may pass through except between a dwelling and a stairway, passageor duct where the pipes and ducts are protected to satisfy Part D;

H


(H2.1), (H2.3)

c. chases for services are allowed in wall type 1 or 2 provided the depth of any horizontal chasedoes not exceed one-sixth of the thickness of the leaf, and the depth of any vertical chase doesnot exceed one-third of the thickness; chases back to back in a single leaf are not permitted; inwall type 3 services may pierce the free-standing panels provided any gaps are sealed with tapeor caulking; no services are permitted in wall type 4; and

d. flues are only permitted in walls where the flues are of masonry construction (including precastconcrete flue blocks); no flues are permitted in wall type 4.

9 In any separating floor being built to meet the specified construction standard no openings are permit-ted except openings for service ducts, pipes or flues protected to satisfy Part D or Part F and which arealso enclosed above and below the floor to satisfy this Part.

H


(H2.1), (2.3)

10 Wall type 1: solid masonryThe resistance to airborne sound dependsmainly on the mass of the wall.

Points to watchFill masonry joints with mortar (to achieve themass and avoid air paths).

Limit the pathways around the wall (to reduceflanking transmission).

ConstructionFive wall constructions which give suitableresistance to direct transmission are specified.Details of how junctions must be made to limitflanking transmission follow.

A. Brick, plastered both sides.Mass including plaster 375 kg/m2. 13 mm plaster each side.Lay bricks in a bond which includesheaders.Example: 215 mm brick, lightweightplaster, 75 mm coursing; brick density of1610 kg/ m3 gives the required mass.

B. Concrete block, plastered both sides. Massincluding plaster 415 kg/m2.13 mm plaster each side.Use blocks which extend to the full thick-ness of the wall.Example: 215 mm block, lightweightplaster, 110 mm coursing; block density of1840 kg/m3 gives the required mass.

C. Brick, plasterboard both sides.Mass including plasterboard 375 kg/m2.12.5 mm plasterboard each side, use anynormal fixing method.Lay bricks in a bond which includesheaders.Example: 215 mm brick, 75 mm coursing;brick density of 1610 kg/m3 gives therequired mass.

D. Concrete block, plasterboard both sides.Mass of masonry alone 415 kg/m2.12.5 mm plasterboard each side, use anynormal fixing method.Use blocks which extend to the full thick-ness of the wall.Example: 215 mm block, 150 mm cours-ing; block density of 1840 kg/m3 gives therequired mass.

E. Concrete (minimum density 1500 kg/m3),in-situ or large panel.Plaster optional.Mass (including plaster if used) 415 kg/m2.Fill joints between panels with mortar.Example: an unplastered wall of density2200 kg/m3; 190mm thickness gives therequired mass.

H


(H2.1), (H2.3)

10. Junctions for wall type 1(Cont’d)

RoofFire-stop the joint between wall and roof (see Part D).

Ceiling and roof spaceWhere there is a heavy ceiling with sealed joints(12.5 mm plasterboard or equivalent), the mass ofthe wall above the ceiling may be reduced to 150kg/m2. If lightweight aggregate blocks are used toreduce mass, seal one side with cement paint orplaster skim.

Intermediate and ground floorsWith a timber floor do not build joists into thewall, use hangers. With a concrete floor either thewall or the floor may be carried through.

External wall The outer leaf of a cavity wall may be of any con-struction. Where a cavity wall has an inner leaf ofmasonry; or where the external wall is of solidmasonry -

a. i. the masonry of the walls must be bondedtogether, or

ii. the masonry of the external wall mustabut the separating wall and be tied to itwith ties at no more than 300 mm centresvertically,

to create a homogeneous unit; and b. the masonry must have a mass of 120 kg/m2

unless the length of the external wall islimited by openings,

i. of 1 metre high,

ii. on both sides of the separating wall atevery storey, and

iii. not more than 700 mm from the face ofthe separating wall on both sides1.

Where a cavity wall has an inner leaf of timber construction it must -

c. abut the separating wall;

d. be tied to it with ties at no more than 300 mmcentres vertically; and

e. have the joints sealed with tape or caulking .1. a short length of wall will not vibrate exces-

sively at low frequencies to give flankingtransmissions.

PartitionsThere are no restrictions on a partition wallmeeting a type 1 separating wall.

H


(H2.1), (H2.3)

��Roof

Ceiling

Intermediatefloor

Groundfloor

concrete

concrete

timber

timber

Section

External wall

masonry

Plan

timber

caulkingor tape

11. Wall type 2: cavity masonry

The resistance to airborne sound depends onthe mass of the leaves and on the degree of iso-lation achieved.

Points to watchFill masonry joints with mortar (to achieve themass and to avoid air paths).Maintain the cavity up to the underside of theroof.Connect the leaves only where necessary forstructural reasons. Use only butterfly patternties, spaced no more than 900 mm apart hori-zontally and 450 mm apart vertically. (BS5628: Part 3: 1985 limits this tie type andspacing to cavities of 50 mm to 75 mm with aminimum masonry leaf thickness of 90 mm).If external walls are to be filled with an insu-lating material other than loose fibre the insu-lating material must be prevented fromentering the cavity in the separating wall.

ConstructionsTwo wall constructions (A and B) which givesuitable resistance to direct transmission arespecified.Two other wall constructions (C and D) will besuitable between houses provided a step in ele-vation and/or a stagger in plan is incorporatedat the separating wall.Details of how junctions must be made to limitflanking transmission follow.

A. Two leaves of brick with 50 mm cavity,plastered on both room faces.Mass including plaster 415 kg/m2. 13 mmplaster each face.Example: 102 mm leaves, lightweightplaster, 75 mm coursing; brick density of1970 kg/m3 gives the required mass.

B. Two leaves of concrete block with 50 mmcavity, plastered on both room faces.Mass including plaster 415 kg/m2. 13 mmplaster each face.Example: 100 mm leaves, lightweightplaster, 225 mm coursing; block density of1990 kg/m3 gives the required mass.

H


(H2.1), (H2.3)

50

11. Additional constructions permitted only where a step and/or stagger of at least 300 mm is used(Cont’d)

C. Two leaves of concrete block with 50 mmcavity, plasterboard on both room faces.Mass of masonry alone 415 kg/m2.12.5 mm plasterboard each face, use anynormal fixing method.Example: 100 mm leaves, 225 mm cours-ing; block density of 1990 kg/m3 gives therequired mass.

D. Two leaves of lightweight aggregate con-crete block (maximum density 1500kg/m3) with 75 mm cavity, plastered onboth room faces.Mass including plaster 250 kg/m2. 13 mmplaster each face.Seal the face of the blockwork, withcement paint or plaster, through the fullwidth and depth of any intermediate floor.Example: 100 mm leaves, lightweightplaster, 225 mm coursing; block density of1105 kg/m3 gives the required mass.

H


(H2.1), (H2.3)

75

50

11. Junctions for wall type 2(Cont’d)

RoofFire-stop the joint between wall and roof (seePart D).

Ceiling and roof spaceWhere there is a heavy ceiling with sealedjoints (12.5 mm plasterboard or equivalent),the mass of the wall above the ceiling may bereduced to 150 kg/m2. The cavity must still bemaintained. If lightweight aggregate blocks areused to reduce mass, one face of the wall mustbe sealed with cement paint or plaster skim.

Intermediate and ground floorsWith a timber floor use joist hangers for anyjoists supported on the wall.With a concrete intermediate or suspendedground floor the floor may be carried throughonly to the cavity face of each leaf.A concrete slab on the ground may be continuous.

External wallThe outer leaf of a cavity wall may be of anyconstruction.Where a cavity wall has an inner leaf ofmasonry -a. i. the masonry of the walls must be

bonded together, orii. the masonry of the external wall must

abut the separating wall and be tied toit with ties at no more than 300 mmcentres vertically,

to create a homogeneous unit; andb. the masonry must have a mass of

120 kg/m2 except where separating walltype 2 is used when there is no minimumrequired mass.

Where a cavity wall has an inner leaf of timberconstruction it must -c. abut the separating wall;d. be tied to it with ties at no more than

300 mm centres vertically; and e. have the joints sealed with tape or

caulking.The cavity in the separating wall must only besealed in accordance with Part D.

PartitionsThere are no restrictions on partition wallsmeeting a type 2 separating wall.

H


(H2.1), (H2.3)

��Roof

Ceiling

��

Intermediatefloor

Ground floor

concrete

concrete

timber

timber

Section

External wall

masonry

Plan

timber

caulkingor tape

12. Wall type 3: solid masonry between isolated panels

The resistance to airborne sound depends onthe mass and type of core and on the isolationand mass of the panels.

Points to watchFill masonry joints with mortar (to achieve themass and to avoid air paths).Support the panels only from floor and ceiling- do not fix or tie them to the masonry core (tomaintain isolation).

ConstructionsFour masonry cores and two panels are speci-fied which in any combination of core pluspanels give suitable resistance to direct trans-mission.Details of how junctions must be made to limitflanking transmission follow.

Basic constructionA masonry core, with an isolated panel on eachside.Minimum air space between panels and core25 mm. Keep framing clear of core (at least 5 mm).

Masonry cores A. Brick

Mass 300 kg/m2.Example: 215 mm core, 75 mm coursing;brick density of 1290 kg/m3 gives therequired mass.

B. Concrete blockMass 300 kg/m2.

Example: 140 mm core, 110 mm coursing;block density of 2200 kg/m3 gives therequired mass.

C. Lightweight aggregate concrete block(maximum density 1500 kg/m3).Mass 200 kg/m2.Example: 140 mm core, 225 mm coursing;block density of 1405 kg/m3 gives therequired mass.Example: 215 mm core, 150 mm coursing;block density of 855 kg/m3 gives therequired mass.

D. Autoclaved aerated concrete block. Mass160 kg/m2.

Example: 200 mm core, 225 mm coursing;block density of 730 kg/m3 gives therequired mass.

H


(H2.1), (H2.3)

25 25

Any framingmust be keptclear of themasonrycore

12. Panels(Cont’d)

E. Two sheets of plasterboard joined by a cel-lular core.Mass (including plaster finish if used) 18 kg/m2

Fix to ceiling and floor only. Tape jointsbetween panels.

F. Two sheets of plasterboard with jointsstaggered.

Thickness of each sheet 12.5 mm if a sup-porting framework is used, or total thick-ness of 30 mm if no framework is used.

Junctions for wall type 3

RoofFire-stop the joint between masonry core androof (see Part D).

Ceiling and roof spaceWhere there is a heavy ceiling with sealedjoints (12.5 mm plasterboard or equivalent),the free-standing panels may be omitted in theroof space and mass of the core above theceiling may be reduced to 150 kg/m2. If light-weight aggregate blocks are used to reducemass, seal one side with cement paint or plasterskim. Seal the junction between ceiling andfree-standing panels with tape or caulking.

Intermediate and ground floorsWith a timber intermediate floor use joisthangers for any joists supported on the walland seal the spaces between joists with fulldepth timber battens.With a concrete intermediate floor the floorbase may only be carried through where it hasa mass of 365 kg/m2. Seal the junction betweenceiling and panel with tape or caulking.The ground floor must be a solid slab, laid onthe ground to prevent air paths.

H


(H2.1), (H2.3)

�Roof

Ceiling

Caulkingor tape

concrete floorbuilt in (only ifgreater than365kg/m2)

timber joists atright angles

ground floormust be solidand may passthrough wall

Section

Ground floor

timber joistsparallel

12. External wall(Cont’d)

The outer leaf of a cavity wall may be of anyconstruction.

The inner leaf of a cavity wall must have aninternal finish of isolated panels as specifiedfor the separating wall except where the separating wall has core A or B when plasteror dry-lining with joints sealed with tape orcaulking may be used.

A layer of insulation may be added to suchinternal finish provided the 25 mm and 10 mmgaps shown in the diagram are maintained.

The inner leaf may be of any construction if itis lined with isolated panels.

If the inner leaf is dry-lined it must be masonrywith a mass of 120 kg/m2, butt jointed to theseparating wall core with ties at no more than300 mm centres, vertically.

PartitionsPartitions abutting a type 3 separating wallmust not be of masonry construction.

Other loadbearing partitions should be fixed tothe masonry core through a continuous pad ofmineral fibre quilt.

Non-loadbearing partitions should be tightbutted to the isolated panels.

All joints between partitions and panels mustbe sealed with tape or caulking.

H


(H2.1), (H2.3)

25 25

25 10

External wall

free-standingpanel lining

dry-liningalternativefor core typesA&B only

Plan

�Loadbearingpartition

Non-loadbearingpartition

Plan

13. Wall type 4: timber frames with absorbent curtain

The resistance to airborne sound depends onthe isolation of the frames plus absorption inthe air space between.

LimitationsPart D places limits on the storey height atwhich this type may be used. The special wallsspecified in Part D for common stairs are suit-able to resist sound transmission provided iso-lation of the leaves is maintained.

Points to watchOnly connect frames if necessary for structuralreasons, and then use as few ties as possible -not more than 14-16 gauge (40 mm x 3 mm)metal straps fixed at or just below ceiling level,1.2 m apart.Services must not be contained in the wall.This is a structural fire precaution (see Part D)but also prevents the creation of air pathsthrough the lining. Where fire-stops are neededin the cavity between frames they must eitherbe flexible or fixed to only one frame.

ConstructionsTwo constructions which, with appropriatecladding and absorbent curtain, give suitableresistance to direct transmission are specified.Details of how junctions must be made to limitflanking transmission follow.

Basic constructionA. Timber frames, 200 mm between

claddings, plus absorbent curtain in cavity.Plywood sheathing may be used in thecavity as necessary for structural reasons.

B. Timber frames, masonry core, plusabsorbent curtain in a cavity. Claddings200 mm apart (ignore core).Framing must be clear of core by 5 mm.

H


(H2.1), (H2.3)

�absorbentcurtain (positionmay vary - seespecification E)

plywoodsheathingif necessary

200between claddings

��

absorbent curtain(position may vary - seespecification E)

200between claddings

5 5

13. Masonry core(Cont’d)

C. This does not normally improve soundresistance but may be useful for supportand in stepped or staggered situations.There are no restrictions on type but thecore may be connected to only one frame.

CladdingD. On each side: two or more layers of plas-

terboard, combined thickness 30 mm,joints staggered to avoid air paths.

Absorbent curtainE. Unfaced mineral fibre quilt (which may be

wire reinforced), density 12-36 kg/m3,thickness 25 mm if suspended in thecavity between frames, 50 mm if fixed toone frame, or 25 mm per quilt if one fixedto each frame.

Junctions for wall type 4

RoofFire-stop the joint between wall and roof (seePart D).

Ceiling and roof spaceCarry the complete construction through to theunderside of the roof. Provision of a ceiling ofany type is optional.

Intermediate floor and ground floor Block the air path to the wall cavity either bycarrying the cladding through the floor or byusing a solid timber edge to the floor. Wherethe joists are at right angles to the wall, sealspaces between joists with full depth timberbattens.

External wallThere are no restrictions on a traditional timberframed wall but if the wall is of cavity construction. the cavity must be sealedbetween the ends of the separating wall and theouter leaf to prevent air gaps.

The internal finish must be 12.5 mm plaster-board or other equally heavy material (resilientlayers for thermal insulation may be incorpo-rated if desired).

Partitions There are no restrictions on partitions meetinga type 4 separating wall.

H


(H2.1), (H2.3)

��

��

Groundfloor

solid slabmay extendinto wall leaf

caulkingor tape

Intermediatefloor

absorbentcurtain(position mayvary, seespecification E) Ceiling

Roof

Section

External wall

caulkingor tape

Plan

14. Floor type 1: concrete base with soft covering

The resistance to airborne sound depends onthe mass of the concrete base and on eliminat-ing air paths. The soft covering reduces impactsound at source.

LimitationsWhere resistance to airborne sound only isrequired the soft covering may be omitted. Noother part of the construction may be omittedas this would reduce airborne sound resistance.

Points to watchFill all joints between parts of the floor to avoidair paths.Limit pathways around the floor to reduceflanking transmission.Workmanship and detailing must be givenspecial attention at the perimeter and whereverthe floor is penetrated by a pipe or duct to reduceflanking transmission and to avoid air paths.

ConstructionsFour floor bases which give suitable resistanceto direct transmission of airborne sound arespecified, followed by the soft covering whichmust be added to give suitable resistance toimpact sound transmission.Details of how junctions must be made to limitflanking transmission follow.

Floor basesA. Solid concrete slab (in-situ).

Floor screed and/or ceiling finish optional.Mass (including any screed and/or ceilingfinish) 365 kg/m2.

B. Solid concrete slab with permanent shut-tering.Floor screed and/or ceiling finish optional. Mass (including shuttering only if it issolid concrete or metal and including anyscreed and/or ceiling finish) 365 kg/m2.

C. Concrete beams with infilling blocks.Floor screed and/or structural toppingmust be used.Ceiling finish optional.Mass of beams, blocks, any structuraltopping and screed (including any ceilingfinish) 365 kg/m2.

D. Concrete planks (solid or hollow).Floor screed and/or structural toppingmust be used.Ceiling finish optional.Mass of planks, any structural topping andscreed (including any ceiling finish) 365 kg/m2.

H


(H2.1), (H2.3)

Sections

14. Soft covering(Cont’d)

E. Any resilient material, or material with aresilient base, with an overall uncom-pressed thickness of 4.5 mm. (A materialis resilient if it returns to its original thick-ness after it has been compressed). Thesoft covering must be bonded to the floorbase.

Junctions for floor type 1

External wall or cavity separating wallThe mass of the wall leaf adjoining the floormust be 120 kg/m2 (including any plaster)except where the area of openings in the exter-nal wall exceeds 20% of its area there is nominimum mass requirement for such a wall.The floor base (excluding any screed, even in Cand D) must pass through the leaf whetherspanning parallel to, or at right angles to, thewall. The cavity must not be bridged.

Internal wall or solid separating wallIf the wall mass is less than 355 kg/m2 includ-ing any plaster then the floor base excludingany screed must pass through.If the wall mass is more than 355 kg/m2 includ-ing any plaster either the wall or the floor baseexcluding any screed may pass through. Wherethe wall does pass through, tie the floor base tothe wall and grout the joint.

Floor penetrationsDucts or pipes penetrating the floor must be inan enclosure, both above and below the floor.Either line the enclosure, or wrap the duct orpipe within the enclosure, with 25 mm unfacedmineral fibre.The material of the enclosure must have a massof 15 kg/m2.Penetrations of a separating floor by ducts andpipes must have fire protection in accordancewith Part D.Where permitted by Part F, a flue-pipe maypenetrate the floor. Unless the flue-pipe dis-charges into a flue within a chimney carried bythe floor, a non-combustible enclosing ductwith mineral fibre absorbent must be provided.

H


(H2.1), (H2.3)

unfacedmineral fibre

unfacedmineral fibre

enclosure

enclosure

caulking

caulking

Sections

15. Floor type 2: concrete base with floating layer

The resistance to airborne sound dependsmainly on the mass of the concrete base andpartly on the mass of the floating layer. Resis-tance to impact sound depends on a resilientlayer from the base and from the surroundingconstruction.

LimitationsWhere resistance to airborne sound only isrequired the full construction must still beused.

Points to watchFill all joints between parts of the floor base toavoid air paths.Limit the pathways around the floor to reduceflanking transmission.Workmanship and detailing must be givenspecial attention at the perimeter and whereverthe floor is penetrated to reduce flanking trans-mission and to avoid air paths.Take care not to create a bridge between thefloating layer and the base, surrounding walls,or adjacent screeds.With bases C and D a screed is recommendedto accommodate surface irregularities andprevent reduced resistance at joints.

ConstructionsFour floor bases, two floating layers and oneresilient layer are specified. Any combinationof base, resilient layer and floating layer givesuitable resistance to direct transmission. Twoadditional resilient layers which may be usedunder screeds only are also specified (H and I).Details of how junctions must be made to limitflanking transmission follow.

Floor basesA. Solid concrete slab (in-situ).

Floor screed and/or ceiling finish optional.Mass (including any screed and/or ceilingfinish) 300 kg/m2.

B. Solid concrete slab with permanent shut-tering.Floor screed and/or ceiling finish optional.Mass (including shuttering only if it issolid concrete or metal, and including anyscreed and/or ceiling finish) 300 kg/m2.

H


(H2.1), (H2.3)

Sections

15. C. Concrete beams with infilling blocks.(Cont’d)

Floor screed/structural topping/ceilingfinish optional. (A levelling screed isrequired where the floating layer is atimber raft.) Mass of beams and blocksand any structural topping (including anyscreed and/or ceiling finish) 300 kg/m2.

D. Concrete planks (solid or hollow).Floor screed/structural topping/ceilingfinish optional.Mass of planks and any structural topping(including any screed and/or ceilingfinish) 300 kg/m2.

Floating layersE. Timber raft.

Timber boarding or wood based board, 18 mm thick with tongued and groovededges, fixed to 45 x 45 mm battens. The raftmust be laid loose on the resilient layer.

F. Screed.65 mm cement sand screed with meshunderlay to protect the resilient layerwhile the screed is being laid.

Resilient layerG. 25 mm mineral fibre, density 36 kg/m3.

A 13 mm thickness may be used under atimber raft if the battens used have an inte-gral closed cell resilient foam strip. Lay the fibre tightly butted and turned upat the edges of the floating layer.Under a timber raft, fibre may be paperfaced on the underside.Under a screed, fibre must be paper facedon upper side to prevent screed enteringthe layer.

Additional resilient layers for use underscreeds only.H. 13 mm pre-compressed expanded poly-

styrene board (impact sound duty grade).Lay boards tightly butted, use on edge as aresilient strip at edges of floating screed.

I. 5 mm extruded (closed cell) polyethylenefoam, density 30-45 kg/m3. To protect thematerial from puncture it should be laidover a levelling screed. Lay with jointslapped.

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(H2.1), (H2.3)

Sections

15. Junctions for floor type 2 (Cont’d)

External wall or cavity separating wall.The mass of the leaf adjoining the floor mustbe 120 kg/m2 (including any plaster) exceptwhere the area of openings in the external wallexceeds 20% of its area there is no minimummass requirement.The floor base (excluding any screed) mustpass through the wall whether spanning paral-lel to or at right angles to the wall.The cavity must not be bridged.Carry the resilient layer up at all edges toisolate the floating layer.Leave a 3 mm gap between skirting and float-ing layer or turn resilient layer under skirting.A seal is not necessary but if used must be flex-ible.

Internal wall or solid separating wallIf the wall mass is less than 355 kg/m2 includ-ing any plaster then the floor base excludingany screed must pass through.If the wall mass is more than 355 kg/m2 includ-ing any plaster either the wall or the floor baseexcluding any screed may pass through. Wherethe wall does pass through tie the floor base tothe wall and grout the joint.

Floor penetrationsDucts or pipes penetrating the floor must be inan enclosure, both above and below the floor.Either line the enclosure, or wrap the duct orpipe within the enclosure, with 25 mm unfacedmineral fibre.The material of the enclosure must have a massof 15 kg/m2.Penetrations of a separating floor by ducts andpipes must have fire protection in accordancewith Part D.Leave a 3 mm gap between enclosure andfloating layer and seal with acrylic caulking orneoprene.Where permitted by Part F, a flue-pipe maypenetrate the floor. Unless the flue-pipe dis-charges into a flue within a chimney carried bythe floor a non-combustible enclosing ductwith mineral fibre absorbent must be provided.

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(H2.1), (H2.3)

��

floating layerresilient layerscreed

floor

�

��unfaced mineral fibreenclosure caulking

caulking

��

unfaced mineral fibreenclosure caulking

caulking

Sections

16. Floor type 3: timber base with floating layer

The resistance to airborne sound dependspartly on the structural floor plus absorbentblanket or deafening, and partly on the floatinglayer. Resistance to impact sound depends on aresilient layer isolating the floating layer fromthe base and the surrounding construction.

LimitationsWhere resistance to airborne sound only isrequired the full construction must still beused.Part D places limits on the storey height atwhich this type may be used. This type can also be used as a specified con-struction for converted properties. Use is onlypermitted with appropriate adjoining walls (see“Junctions” below).

Points to watchLimit the pathways around the floor (to reduceflanking transmission).Workmanship and detailing must be givenspecial attention at the perimeter and whereverthe floor is penetrated (to reduce flankingtransmission and to avoid air paths).Use the correct density of resilient layer.Take care not to bridge between the floatinglayer and the base or surrounding walls (e.g.with services or fixings which penetrate theresilient layer). Allow for movement of materi-als e.g. expansion of chipboard after laying (tomaintain isolation).

ConstructionsThree complete constructions which give suit-able resistance to direct sound transmission arespecified. Note that there are some alternativeswithin each construction.Details of how junctions must be made to limitflanking transmission follow.

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16. Floors(Cont’d)

A. Platform floor with absorbent blanket.Either a floating layer of timber or woodbased board, 18 mm thick, with tonguedand grooved edges and all joints glued,spot bonded to substrate of 19 mm plaster-board; or a floating layer of two thick-nesses of cement bonded particleboardwith joints staggered, glued and screwedtogether, total thickness 24 mm.Resilient layer of 25 mm mineral fibre,density 60-100 kg/m3. Note that the lowfigure gives the best insulation but a “soft”floor.Floor base of 12 mm timber boarding orwood-based board nailed to timber joists(size to suit the structure).Ceiling of two layers of plasterboard withjoints staggered, total thickness 30 mm,with an absorbent blanket of 100 mmunfaced mineral fibre, density 12-36kg/m3, laid on the ceiling.

B. Heavy ribbed floor with absorbentblanket.Floating layer of timber or wood basedboard, 18 mm thick with tongued andgrooved edges and all joints glued, spotbonded to substrate of 19 mm plasterboardnailed to 45 mm x 45 mm timber battensplaced on the joists.Resilient strips of 25 mm mineral fibre,density 80-140 kg/m3, laid on joists.Floor base of 45 mm thick timber joists.Ceiling of two layers of plasterboard withjoints staggered, total thickness 30 mm,with an absorbent blanket of 100 mmunfaced mineral fibre, density 12-36 kg/m3, laid on the ceiling .

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(H2.1), (H2.3)

�� floating layer

resilient layerfloor base

absorbentblanket

ceiling

��floating layerbatten resilient layer

absorbentblanket

ceiling

�Sections

16. C. Ribbed floor with heavy deafening†

(Cont’d)

Floating layer of timber or wood basedboard, 18 mm thick with tongued andgrooved edges and all joints glued, nailedto 45 mm x 45 mm timber battens placedeither on or between joists (for sheet mate-rials, placing on joists is recommended).Resilient strips of 25 mm mineral fibre,density 80-140 kg/m3, laid on joists.Floor base of 45 mm thick timber joists.Ceiling of either 19 mm dense plaster onexpanded metal lath or 6 mm plywoodfixed under the joists plus two layers ofplasterboard with joints staggered, totalthickness 25 mm. Both types of ceiling tohave deafening of mass 80 kg/m2 laid on apolyethylene layer.

† Deafening (pugging) may be of the fol-lowing types:Traditional ash (75 mm), or2-10mm limestone chips (60 mm), or2-10 whin aggregate (60 mm), or Dry sand (50 mm).Figures in brackets show approximatethickness required to achieve 80 kg/m2.Do not use sand in kitchens, bathrooms,shower rooms or watercloset compart-ments.


Timber frame wallSeal the gap between wall and floating layerwith a resilient strip glued to the wall.Leave a 3 mm gap between skirting and float-ing layer. A seal is not necessary but if usedmust be flexible. Block air paths between thefloor base and the wall, including the spacebetween joists when joists are at right angles tothe wall. Seal the junction of ceiling and wall with tapeor caulking.

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(H2.1), (H2.3)

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Sections

��resilientstrip

timberframewall

floating layerresilient strip

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linerplywoodceiling

caulkingor tape

16. Heavy masonry leaf (Cont’d)

Mass of leaf (including any plaster) 355 kg/m2, both above and below floor.Seal the gap between wall and floatinglayer with a resilient strip glued to the wall.Leave a 3 mm gap between skirting andfloating layer. A seal is not necessary but ifused must be flexible. Use any normalmethod of connecting floor base to wall.Seal the junction of ceiling and wall liningwith tape or caulking.

Light masonry leafIf the mass (including any plaster) is lessthan 355 kg/m2 a free-standing panel asspecified in wall type 3 must be used.Seal the gap between wall and floatinglayer with a resilient strip glued to the free-standing panel.Leave a 3 mm gap between skirting andfloating layer. A seal is not necessary but ifused must be flexible. Use any normalmethod of connecting floor base to wall butblock air paths between floor and wall cav-ities.Take ceiling through to masonry, seal junc-tion with free-standing panel with tape orcaulking.

Floor penetrationsDucts or pipes penetrating the floor must bein an enclosure both above and below thefloor.Either line the enclosure, or wrap the ductor pipe within the enclosure, with 25 mmunfaced mineral fibre.The material of the enclosure must have amass of 15 kg/m2.Penetrations of a separating wall by ductsand pipes must have fire protection inaccordance with Part D.Leave a 3 mm gap between enclosure andfloating layer, seal with acrylic caulking orneoprene. Enclosure may go down to thefloor base if specification A is used, butkeep isolation of enclosure from floatinglayer.Where permitted by Part F, a flue-pipe maypenetrate the floor. The flue-pipe must be ina non-combustible enclosing duct withmineral fibre absorbent.Seal the junction of ceiling and enclosurewith tape or caulking.

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(H2.1), (H2.3)

�Sections

��resilient

strip floating layerresilient strip

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linerplywoodceilingcaulkingor tape

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resilientstrip

resilientstrip

floating layerresilient strip

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unfaced mineral fibre

linerplywoodceiling

ceiling

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25

25��

seal

seal

seal

seal

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Floor penetration (type A floor shown)

Floor penetration (type C floor shown)

floating layer resilient layer

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unfaced mineralfibre

floor base

absorbent blanket

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17. Floor type 4: timber base with independent ceiling

The resistance to airborne and impact sounddepends mainly on the mass and isolation ofthe independent ceiling and partly on the massof the floor base.

Limitations Where resistance to airborne sound only isrequired the full construction must still beused. Part D places limits on the storey height atwhich this type may be used. It must only beused with heavy masonry walls. It is mainly for use as a specified constructionfor converted properties with suitable existingfloors and walls.

Points to watch Limit the pathways around the floor, especiallyat the edges of the independent ceiling (toreduce flanking transmission and to avoid airpaths). Workmanship and detailing must be givenspecial attention wherever the floor is pene-trated. Take care not to create bridges between thefloor base and the independent ceiling.

ConstructionThe floor and independent ceiling specifiedbelow, together give suitable resistance todirect sound transmission. Details of how junctions must be made to limitflanking transmission follow.

FloorTimber boarding or wood based board, 18 mmthick with tongued and grooved edges (or 3.2mm hardboard over the whole floor to sealgaps).45 mm thick joists plus deafening of mass 80 kg/m2 and a ceiling of either 19 mm denseplaster on lath or two layers of plasterboardwith joints staggered, total thickness 30 mm. Inexisting floors deafening may be on boardsbetween joists, in new floors use 6 mmplywood fixed to underside of joists. A polyethylene liner may be used if desired.

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(H2.1), (H2.3)

��

150

Section (through new floor)

boarding orboard

deafening

liner (optional)

false ceiling(plasterboardoption)

unfacedmineralfibre

ceiling

��

150

Section (through adapted existing floor)

boarding orboard

deafening

plywoodfalse ceiling(plaster option)

unfacedmineralfibre

ceiling

17. Independent ceiling (Cont’d)

Absorbent blanket of 25 mm unfaced mineralfibre, density 12-36 kg/m3, draped over 45 mmthick joists supported independently of thefloor. Ceiling of two layers of plasterboardwith joints staggered, total thickness 30 mm.Keep ceiling 150 mm away from the undersideof the floor base.


External wall or separating wallMass of leaf must be 355 kg/m2 (including anyplaster), both above and below the floor, on atleast 3 sides. Leaf on fourth side must be atleast 180 kg/m2.Use bearers on walls to support the edges of theceiling and to block air paths.Seal the junction of ceiling and wall with tapeor caulking.

Internal wallIf masonry, mass must be 180 kg/m2. No restriction if stud partition.Support and seal as for external walls.

Floor penetrationsDucts or pipes penetrating the floor must be inan enclosure both above and below the floor.Either line the enclosure, or wrap the duct orpipe within the enclosure, with 25 mm unfacedmineral fibre.The material of the enclosure must have a massof 15 kg/m2.Penetrations of a separating floor by ducts andpipes must have fire protection in accordancewith Part D.Where permitted by Part F, a flue-pipe maypenetrate the floor. The flue-pipe must be in anon-combustible enclosing duct with mineralfibre absorbent.Seal the junction of ceiling and enclosure withtape or caulking.

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(H2.1), (H2.3)

boarding orboard

deafening

plywood

false ceiling(plaster option)


ceilingseal

boarding or board

deafening

plywood

false ceiling(plaster option)


unfaced mineral fibre

ceiling

enclosure

enclosure

trimmer

seal

Sections

Performance standards and test procedures

Standards

18. A wall or floor will meet the requirements for sound insulation if the following values are achieved whenthe performance is tested after construction under the procedures set out in 19 to 29.

Airborne Sound Minimum values of weighted standardised level difference(DnT,w) as defined in BS EN ISO 717-1: 1997

Mean Value (dB) Individual Value (dB)

Walls 53 49Floors 52 48

Impact Sound Maximum values of weighted standardised impact sound pressure level

(L’nT,w) as defined in BS EN ISO 717-2: 1997

Mean Value (dB) Individual Value (dB)

Floors 61 65

Test procedures

19. For each wall or floor which requires to be tested take four sets of measurements, or as close to four aspossible given the following restrictions -

a. for each set of measurements use a pair of rooms if possible;

b. use a pair consisting of a room and some other space only where necessary to make up the four sets;

c. use a pair consisting of spaces other than rooms only where no other measurement is possible; and

d. take only one set of measurements between each pair.

20. When measuring between a pair of rooms of unequal area, the sound source must be in the larger room.

21. When measuring between a room and some other space, the sound source must be in the other space.

22. Carry out the tests for airborne sound in accordance with BS EN ISO 140-4: 1998 and for impact soundin accordance with BS EN ISO 140-7: 1998. The tests are to be done in completed but unfurnisheddwellings. Doors and windows must be closed. The tests will determine the standardised level differ-ences (DnT) for airborne sound transmission and the standardised impact sound pressure levels (L’nT)for impact sound transmission.

23. For each set of measurements calculate the weighted standardised level difference (DnT,w) in accor-dance with BS EN ISO 717-1: 1997 or the weighted standardised impact sound pressure level (L’nT,w)in accordance with BS EN ISO 717-2: 1997.

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(H2.1), (H2.3)

24. The calculated value from each set of measurements must be no worse than that stated in the “Individ-ual Value” column in point 18.

25. The mean of the four† calculated values must be no worse than that stated in the “Mean Value” columnin point 18. † where only two or three sets of measurements have been possible the mean must still be reached, andwhere only one set is possible the value achieved must not be worse than the mean value.

26. In a building every wall or floor, or part of a wall or floor, which requires sound resistance and is of nom-inally identical construction, may be regarded as forming part of a single wall or floor e.g. in a blockof flats a wall rising through several storeys may be regarded as a single wall, and floors over a wholestorey may be regarded as a single floor, wherever the flat plans are nominally identical.

27. A wall which changes construction only in a roof space may be regarded as a single wall.

28. In any group of dwellings covered by one building warrant, walls and floors of nominally identicaldwelling types which are similarly situated in regard to adjoining buildings may all be regarded asmeeting the performance standard if the ones selected for test meet the standard.

29. Note that the test procedure described above is intended only to provide evidence that a particular wallor floor not built to a specified construction satisfies the performance standards set out in point 18.

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(H2.1), (H2.3)

Documents

RESISTANCE TO THE TRANSMISSION OF SOUND · PDF fileH1.1 This Part sets out the required standards for Regulations 19 to 21. ... Example: 215 mm brick, lightweight plaster, 75 mm coursing;