June Residential Refurbishment Separating walls

Transcription

1 June 2010 Residential Refurbishment Separating walls

2 Residential refurbishment 3.0 Residential Refurbishment Separating Walls Contents Introduction find online page Solution optimiser and pathfinder 298 Design considerations 300 Design Details 650 find online page Timber frame supporting wall (E-WT-1 and E-WT-2) Sw Steel frame supporting wall (E-WS-1) Sw Steel frame supporting wall (E-WS-3) Sw New masonry separating wall Sw Existing masonry into separating wall Sw Timber frame supporting wall Sw Steel frame supporting wall Sw Steel frame supporting wall Sw08 654

3 3.6.1 Residential refurbishment: Internal walls and floors Separating walls Solution optimiser and pathfinder Knauf Insulation offers a range of products for insulating separating walls between dwellings that contribute towards the separating wall systems meeting the design and Building Regulation requirements in a cost effective manner. Using these products also improves the thermal insulation values of the separating elements. Acoustic definitions Acoustic sealant A gun-applied sealant which is resilient when cured. It is used to seal gaps to prevent air movement. C tr The correction to a sound insulation quantity (such as DnT,w) used in Approved Document E that takes greater account of low frequency sounds. See BS EN ISO 717-1:1997. Decibel (db) The unit used in acoustics to quantify sound level with respect to a reference level. It uses a logarithmic scale. An increase of 3 db is roughly double the sound pressure level. D nt The difference in sound level between a pair of rooms, for a stated frequency band, corrected for the reverberation time in the receiving room. See BS EN ISO In other words this is reduction in airborne sound transmission effected by the separating wall at a particular sound frequency. D nt,w The weighted standardised level difference. A single-number quantity (weighted) which characterises the airborne sound insulation between rooms. See BS EN ISO This is a method of expressing the reduction in sound transmission effected by the separating wall for all frequencies of sound. It is attempting to give a real life value to the sound insulation offered by a separating wall. Frequency The number of vibrations per second that gives a sound its distinctive tone. The unit of frequency is the Hertz (Hz). R w A single-number quantity which characterises the airborne sound insulation of a material or building element from measurements undertaken in an acoustic test laboratory. See BS EN ISO L nt The impact sound pressure level in the receiving room at a stated frequency, corrected for the reverberation time. See BS EN ISO In other words this is a measure of the protection from impact sound transmission provided by the separating floor for a particular sound frequency. L nt,w The weighted standardised impact sound pressure level. A single-number quantity (weighted) used to characterise the impact sound insulation of floors. See BS EN ISO In other words this is a measure of the protection from impact sound transmission provided by the separating floor for all frequencies. It is attempting to give a real life value to the protection from impact sound transmission offered by a separating floor. 298

4 Residential refurbishment: Internal walls and floors Internal separating walls Part E requirement Airborne sound D ntw +C tr (higher value = greater protection from airborne sound) Knauf Insulation solution D ntw +C tr (db) Independent lining of existing masonry separating wall Product*: Earthwool Acoustic Partition Roll or Earthwool Flexible Slab Description: Independent metal frame with glass or rock mineral wool slab fitted between the studs Page No: 658 Sw05 2 Timber frame separating wall Product*: Earthwool FrameTherm range Description: Glasswool insulation fitted between studs to both sides of twin timber frame walls 1 Page No: 650 Sw06 Steel frame separating wall Product*: Earthwool Flexible Slab Description: Rock mineral wool insulation fitted between frames of twin metal stud walls 1 1 Page No: 652 Sw07 Steel frame separating wall Product*: Earthwool Universal Slab RS45 Description: Rock mineral wool insulation fitted in metal studs to both sides of twin metal stud walls 1 Page No: 654 Sw08 Key Sound insulation achievable by constructions within this document. * Recommended Knauf Insulation product(s). Other products may be applicable. Pb01 Find online. Visit and key in construction code to find the most up to date information on your chosen solution. 1 This value indicates performance levels that have been achieved when this construction was tested in new build. Necessarily, the variables involved when working with existing buildings mean that this value can only be used as a guide to potential performance in refurbishment work. 2 The condition of the existing wall is a major factor in the performance of this solution, meaning that the value indicated should only be taken as a guide to potential performance. 299

5 3.6.1 Residential refurbishment: Internal walls and floors Separating walls Separating wall design Separating walls are required to provide protection from noise between adjoining dwellings. To achieve the expected level of protection not only does the separating wall have to be designed and built correctly, but particular attention has to be paid to flanking transmission through the building elements adjoining the separating wall. It should be remembered that the performance levels required by Building Regulations and Standards measure the protection offered by the dwelling from an adjoining dwelling, not just the performance of the separating element in isolation. In England and Wales the Building Regulation Part E was revised in 2003 to ensure better performance of properties in this respect. The changes require performance to be established by on-site testing before compliance can be achieved, and place emphasis on low frequency noise. The Building Regulation requirements for England and Wales, Scotland and Northern Ireland are given later in this section. England and Wales Compliance with Approved Document Part E : Construct the separating wall and show compliance by carrying out a sound test, in accordance with the procedures stated in the Document, proving the performance of the wall equals or exceeds the standard set out in Table 10. Scotland and Ireland Section 5 in Scotland, Technical Booklet G in Northern Ireland and Part E in Ireland, compliance can be achieved either by adopting specified constructions or by testing to show that non-specified constructions meet the Performance Standards set out in Tables 11 and 12. Note that Scotland, Northern Ireland and The Republic of Ireland have not adopted the Dn T,w +C tr sound spectrum for testing that must be used in England and Wales. The performance standards are therefore not directly comparable. Separating walls between flats and communal areas Walls between flats and communal areas such as access corridors, not only act as separating walls, but, where the communal areas are unheated, they must also comply with the thermal requirements of the Building Regulations. This favours separating walls constructed of masonry cavity walls and framed constructions, as they can readily accommodate increased thicknesses of mineral wool insulation. BRE publication BR443 Conventions for U-value Calculations, sets out the shelter factors to be applied to separating walls in these locations. Table 10: Performance standards for separating walls England & Wales Dwelling-houses and flats formed by material change of use Airborne Sound Insulation D nt,w +Ctr db (min values) 43 Table 11: Performance standards for separating walls Scotland & NI Airborne Sound Insulation (D nt,w )* Mean value (db) Individual value (db) Separating walls * As defined in BS EN ISO 717-1:

6 Residential refurbishment: Internal walls and floors Table 12: Performance standards for separating walls Republic of Ireland Separating walls Individual value (db) * As defined in BS EN ISO 717-1: 1997 Airborne Sound Insulation (D nt,w )* Mean value in at least 4 pairs (db) Mean value in at least 8 pairs (db)

7 6.5.1 Design details: Separating walls Separating walls Timber frame separating wall ( RD E-WT-1 and E-WT-2) Advantages 3 The two timber frames ensure good acoustic isolation Sw01 Sw06 3 Mineral wool in void absorbs sound and improves acoustic performance 3 Earthwool FrameTherm products, which are being used for thermal insulation of external timber frame walls, meet the specification for mineral wool infill 3 Mineral wool friction fits between studs 3 No need to site test Robust Details 3 Provides a high level of thermal separation between adjoining properties and unheated enclosed spaces, such as stairwells and corridors One layer 19mm Knauf Drywall Plank and one layer12.5mm Knauf Drywall Soundshield each side, joints staggered 90mm Earthwool FrameTherm Products Earthwool FrameTherm is lightweight glass mineral wool available in both slab and roll form. It comes in a range of densities, but all products meet the requirements of Robust Details E-WT-1and E-WT-2 or deemed-to-satisfy solution in Scotland and Northern Ireland. Earthwool Flexible Slab is a semi-rigid non-combustible rock mineral wool slab. Its density meets the requirements of Robust Details E-WT-1and E-WT-2 or deemed-to-satisfy solution in Scotland and Northern Ireland. Earthwool Timber Roll RD10 is a lightweight glass mineral wool roll, its density meets the requirements of Robust Details E-WT-1and E-WT-2. Typical construction Twin timber frame construction with facing of two layers of plasterboard on each side. Mineral wool is inserted in the cavities to absorb sound. The construction above uses 90mm Earthwool FrameTherm between both sets of studs, and complies with Robust Detail E-WT-1 (no sheathing board) and E-WT-2 (with cavity sheathing board as shown). Refer to RD specification sheets and checklists for junction, flanking and other construction details. It should be noted when considering using Robust Details in the construction of flats that separating walls and floors must be compatible. The Robust Detail manual carries details of which walls and floors can be combined together. 60mm Earthwool Flexible Slab and Earthwool Acoustic Timber Roll RD10 can also be used in this application. Installation Two separate stud walls are constructed. 90mm Earthwool FrameTherm is friction fitted between the studs of both timber frames. Two layers of plasterboard, as specified above, fixed to each side of the party wall, all joints staggered. Seal all joints in outer leaf with Knauf Drywall Joint Tape or caulk with Knauf Drywall Sealant. Cavity barriers To meet the requirements of the Building Regulations, cavity barriers must be installed in timber party walls at the junction with external walls and at horizontal floor zones. Earthwool Cavity Barrier and Rocksilk Smoke and Fire Barrier meet this requirement. See pages Performance Acoustic performance This wall construction, if used on a building plot registered with Robust Details Limited, does not require pre-completion testing. In site tests, Robust Detail E-WT-1 has achieved sound reduction results of db. Robust Detail E-WT-2 has achieved sound reduction results of db. Thermal performance Table 84 shows typical U-values. Fire performance Earthwool FrameTherm, Earthwool Flexible Slab and Earthwool Timber Roll RD10 are classified as Euroclass A1 to BS EN ISO

8 Design details: Separating walls Typical wall/floor section 240mm minimum between plasterboard faces Typical specification Robust details E-WT-1 and E-WT-2 One layer 19mm Knauf Drywall Plank and one layer12.5mm Knauf Drywall Soundshield each side, joints staggered Type FFT-1 floating floor with 60mm Earthwool Acoustic Timber Roll RD10 Acoustic sealant Earthwool Cavity Barrier Earthwool FrameTherm, 90mm thick*/ Earthwool Flexible Slab 60mm thick*/ Earthwool Timber Roll RD10* to be friction fitted between the studs. (*Delete as appropriate) Alternatively, consult the National Building Specifications (NBS) based on Standard Version K10/165A. It contains a set of proprietary clauses, which are edited versions written by Knauf Insulation. 100mm Earthwool Acoustic Joist Roll 90mm Earthwool FrameTherm, or 60mm of Earthwool Flexible Slab or 60mm Earthwool Timber Roll RD10 Although this solution was Sw06 developed as a Robust Detail which can be used without on site testing in new build dwellings in England and Wales its use, with the same products, is appropriate as a separating wall in both new build non dwellings such as student accommodation, nursing homes and hotels constructed using timber frame. Similarly, it could be used in refurbishment projects in both dwellings and non dwellings in existing constructions which require new separating walls providing the flanking walls and floors are suitable. In all cases if it is used for work other than new dwellings its performance must be proven by the stipulated on site testing procedures that apply. For dwellings in Scotland and Northern Ireland this solution exceeds the requirements of Specified Wall Type 4A as defined in Technical Handbook 5 Sound (Scotland) and Technical Booklet G 1990 (Northern Ireland) when used with Earthwool FrameTherm Products (except FrameTherm 43) and Earthwool Flexible Slab. As such it can be used without on-site testing. Table 84: U-values of timber frame separating walls Thickness U-values (W/m 2 K) with additional airspace resistance* (m 2 K/W) Product (mm) Earthwool FrameTherm 35 2x Earthwool FrameTherm 40 2x Earthwool Flexible Slab 2x x * The additional airspace resistances are taken from Appendix A of BR 443 as follows: 0.31 for an access corridor with heat loss through the facing wall, plus floor or ceiling 0.43 for an access corridor with heat loss through the floor or ceiling 0.82 for a stairwell with the facing wall exposed 0.90 for a stairwell with the facing wall not exposed. There are specific additional requirements that need to be taken into to consideration when calculating the U-values for elements that are adjacent to unheated spaces. In multi storey dwellings such as flats and apartments the stairwells and access corridors are not regarded as part of the dwelling, and heat losses through the separating elements between the dwelling and the stairwell or access corridor are ignored if they are heated. If the stairwell or access corridor is unheated then the U-value of the walls between the dwelling and the unheated space can be modified by the inclusion of an additional amount of thermal resistance (R u ). The amount of additional thermal resistance that can be included in U-value calculations is dependent on whether or not the wall directly facing the dwelling wall is exposed or un-exposed, the influence of the floors in corridors is also taken into account. Standard default values can be taken from BR443 (Conventions for U-value Calculations) or SAP For situations not covered by default values, or where additional guidance is required contact our Technical Advisory Centre on

9 6.5.1 Design details: Separating walls Separating walls Steel frame separating wall ( RD E-WS-1) Advantages 3 The two frames ensure good acoustic isolation Sw02 Sw07 3 Mineral wool in void absorbs sound and improves acoustic performance 3 No need to site test Robust Detail 3 Provides a high level of thermal separation between adjoining properties and unheated enclosed spaces, such as stairwells and corridors One layer 19mm Knauf Drywall Plank and one layer12.5mm Knauf Drywall Soundshield each side, joints staggered 60mm Earthwool Flexible Slab between frames 70mm C stud frames First layer of plasterboard mounted horizontally, second layer vertically Products Earthwool Flexible Slab is a semi-rigid rock mineral wool slab. Its density meets the requirements of Robust Details E-WS-1. Earthwool Universal Slab CS48 is a semi-rigid glass mineral wool slab. Its density meets the requirements of Robust Details E-WS-1. Typical construction Twin steel frame construction with facing of one layer of 19mm Knauf Drywall Plank and one layer of 12.5mm Knauf Drywall Soundshield plasterboard on each side. 60mm Earthwool Flexible Slab between the frames. Note that two 70mm wide studs and 60mm thick Earthwool Flexible Slab gives an overall thickness of 200mm between the plasterboard faces. The construction complies with Robust Detail E-WS-1. No pre-completion testing is required with Robust Details. Refer to Robust Detail specification sheets and checklists for junction, flanking and other construction details. It should be noted when considering using Robust Details in the construction of flats that separating walls and floors must be compatible. The Robust Detail manual carries details of which walls and floors can be combined together. Installation Two separate steel frame walls are constructed. 60mm Earthwool Flexible Slabs are slotted into the cavity between the two steel frames and butt jointed. There should be no gaps between the slabs. The rows of slabs should be laid broken bond to avoid coincident vertical joints. One layer of 19mm Knauf Drywall Plank and one layer of 12.5mm Knauf Drywall Soundshield must be screwed to each side of the party wall, all joints staggered. Seal all joints in outer leaf with Knauf Drywall Joint Tape or caulk with Knauf Drywall Sealant. Cavity barriers To meet the requirements of the Building Regulations, cavity barriers must be installed in steel party walls at the junction with external walls and at horizontal floor zones. Earthwool Cavity Barrier and Rocksilk Smoke and Fire Barrier meet this requirement. Performance Acoustic performance This wall construction, if used on a building plot registered with Robust Details Limited, does not require pre completion testing. In site tests, Robust Detail E-WS-1 has achieved sound reduction results of db. Thermal performance Table 85 shows the U-values achieved by this construction in various situations where the separating wall adjoins an unheated space. Fire performance Earthwool Flexible Slab and Earthwool Universal Slab CS 48 are classified as Euroclass A1 to BS EN ISO

10 Design details: Separating walls External wall/separating wall junction 300x100mm Earthwool Cavity Barrier 200mm minimum between plasterboard faces One layer of 19mm Knauf Drywall plank and one layer 12.5mm Knauf drywall Soundshield each side. joints staggered Typical specification Earthwool Flexible Slab*/Earthwool Universal Slab CS48*, to be slotted into the cavity between the two steel frames and butt jointed. The slabs should be laid broken bond to avoid continuous vertical joints. (*Delete as appropriate) Alternatively, consult the National Building Specifications (NBS) based on Standard Version K10/125A It contains a set of proprietary clauses, which are edited versions written by Knauf Insulation. Minimum 600mm width of Earthwool Flexible Slab between steel studs either side of separating wall 60mm Earthwool Flexible Slab between frames 70mm C stud frame Although this solution was Sw07 developed as a Robust Detail which can be used without on site testing in new build dwellings in England and Wales, its use with the same products is appropriate as a separating wall in both new build non dwellings such as student accommodation, nursing homes and hotels constructed using light weight steel frames. Similarly, it could be used in refurbishment projects in both dwellings and non-dwellings in existing constructions which require new separating walls, providing the flanking walls and floors are suitable. In all cases, if it is used for work other than new dwellings, its performance must be proven by the stipulated on site testing procedures that apply. For dwellings in Scotland and Northern Ireland there are no approved light steel frame separating wall constructions. Performance must be proven by the stipulated on site testing procedures. Table 85: U-values of separating wall E-WS-1 Product Thickness U-values (W/m 2 K) with additional airspace resistance* (m 2 K/W) (mm) Earthwool Flexible Slab Earthwool Universal Slab CS * The additional airspace resistances are taken from Appendix A of BR 443 as follows: 0.31 for an access corridor with heat loss through the facing wall, plus floor or ceiling 0.43 for an access corridor with heat loss through the floor or ceiling 0.82 for a stairwell with the facing wall exposed 0.90 for a stairwell with the facing wall not exposed. There are specific additional requirements that need to be taken into to consideration when calculating the U-values for elements that are adjacent to unheated spaces. In multi storey dwellings such as flats and apartments the stairwells and access corridors are not regarded as part of the dwelling, and heat losses through the separating elements between the dwelling and the stairwell or access corridor are ignored if they are heated. If the stairwell or access corridor is unheated then the U-value of the walls between the dwelling and the unheated space can be modified by the inclusion of an additional amount of thermal resistance (R u ). The amount of additional thermal resistance that can be included in U-value calculations is dependent on whether or not the wall directly facing the dwelling wall is exposed or un-exposed, the influence of the floors in corridors is also taken into account. Standard default values can be taken from BR443 (Conventions for U-value Calculations) or SAP For situations not covered by default values, or where additional guidance is required contact our Technical Advisory Centre on

11 6.5.1 Design details: Separating walls Separating walls Steel frame separating wall ( RD E-WS-3) Advantages 3 Two frames ensure good acoustic isolation Sw03 Sw08 3 Mineral wool in void absorbs sound and improves acoustic performance 3 No need to site test Robust Details 3 Provides a high level of thermal separation between adjoining properties and unheated enclosed spaces, such as stairwells and corridors 75mm Earthwool Universal Slab RS45 between frames One layer 19mm Knauf Drywall Plank and one layer12.5mm Knauf Drywall Soundshield each side, all joints staggered 72mm C stud frames First layer of plasterboard mounted horizontally, second layer vertically Products Earthwool Universal Slab RS45 is a semi-rigid rock mineral wool slab. Its density meets the requirements of Robust Details E-WS-3. Typical construction Twin steel frame construction with facing of one layer of 19mm Knauf Drywall Plank and one layer of 12.5mm Knauf Drywall Soundshield plasterboard on one side, 75mm Earthwool Universal Slab RS45 between and sheathing on the inner face. This construction is repeated for the second steel frame with a 40mm cavity between the two leaves. The construction complies with Robust Detail E-WS-3. No pre completion testing is required with Robust Details. Refer to RD specification sheets and checklists for junction, flanking and other construction details. It should be noted when considering using Robust Details in the construction of flats that separating walls and floors must be compatible. The Robust Detail manual carries details of which walls and floors can be combined together. Installation Two separate steel frame walls are constructed. Around each steel frame a sandwich of one layer of 19mm Knauf Drywall Plank and one layer of 12.5mm Knauf Drywall Soundshield plasterboard on the outer face, 75mm Earthwool Universal Slab RS45 between and sheathing on the inner face is constructed. There should be no gaps between the slabs. The rows of slabs should be laid broken bond to avoid vertical joints coinciding. One layer of 19mm Knauf Drywall Plank and one layer of 12.5mm Knauf Drywall Soundshield must be screwed to each side of the party wall, all joints staggered. Seal all joints in outer leaf with Knauf Drywall Joint Tape or caulk with Knauf Drywall Sealant. Cavity barriers To meet the requirements of the Building Regulations, cavity barriers must be installed in steel party walls at the junction with external walls and at horizontal floor zones. Earthwool Cavity Barrier and Rocksilk Smoke and Fire Barrier meet this requirement. Performance Acoustic performance This wall construction, if used on a building plot registered with Robust Details Limited, does not require pre completion testing. In site tests Robust Detail E-WS-3 has achieved sound reduction results of db. Thermal performance Typical U-values are shown in Table 86. Fire performance Earthwool Universal Slab RS45 is classified as Euroclass A1 to BS EN ISO

12 Design details: Separating walls External wall/separating wall junction Earthwool Steel FrameTherm Earthwool Cavity Barrier 75mm Earthwool Universal Slab RS45 Typical specification Earthwool Universal Slab RS45, 75mm thick, to be slotted into the cavity between the two steel frames and butt jointed. The slabs should be laid broken bond to avoid continuous vertical joints. Alternatively, consult the National Building Specifications (NBS) based on Standard Version K10/125A It contains a set of proprietary clauses, which are edited versions written by Knauf Insulation. Typically 72mm C studs at 600mm centres Although this solution was developed Sw08 as a Robust Detail, which can be used without on site testing in new build dwellings in England and Wales, its use with the same products, is appropriate as a separating wall in both new build non dwellings such as student accommodation, nursing homes and hotels constructed using light weight steel frames. Similarly, it could be used in refurbishment projects in both dwellings and non-dwellings in existing constructions which require new separating walls, providing the flanking walls and floors are suitable. In all cases, if it is used for work other than new dwellings, its performance must be proven by the stipulated on site testing procedures that apply. For dwellings in Scotland and Northern Ireland there are no approved light steel frame separating wall constructions. Performance must be proven by the stipulated on site testing procedures. Table 86: U-values of separating wall E-WS-3 Product Thickness U-values (W/m 2 K) with additional airspace resistance* (m 2 K/W) (mm) Earthwool Flexible Slab * The additional airspace resistances are taken from Appendix A of BR 443 as follows: 0.31 for an access corridor with heat loss through the facing wall, plus floor or ceiling 0.43 for an access corridor with heat loss through the floor or ceiling 0.82 for a stairwell with the facing wall exposed 0.90 for a stairwell with the facing wall not exposed. There are specific additional requirements that need to be taken into to consideration when calculating the U-values for elements that are adjacent to unheated spaces. In multi storey dwellings such as flats and apartments the stairwells and access corridors are not regarded as part of the dwelling, and heat losses through the separating elements between the dwelling and the stairwell or access corridor are ignored if they are heated. If the stairwell or access corridor is unheated then the U-value of the walls between the dwelling and the unheated space can be modified by the inclusion of an additional amount of thermal resistance (R u ). The amount of additional thermal resistance that can be included in U-value calculations is dependent on whether or not the wall directly facing the dwelling wall is exposed or un-exposed, the influence of the floors in corridors is also taken into account. Standard default values can be taken from BR443 (Conventions for U-value Calculations) or SAP For situations not covered by default values, or where additional guidance is required contact our Technical Advisory Centre on

13 6.5.1 Design details: Separating walls Separating walls New masonry separating wall Advantages Sw04 3 No need to use wet trades as parge coating not required 3 Slabs knit together, thus eliminating air gaps between adjacent slabs 3 Glass mineral wool is non-combustible with Euroclass A1 classification 3 High content of recycled glass used in the manufacturing process Light weight aggregate block Earthwool Acoustic Party Wall Slab Plasterboard on dabs Suitable wall tie Lightweight aggregate block Plasterboard on dabs Products Earthwool Acoustic Party Wall Slab is a 35mm thick foil-faced semi-rigid non-combustible, glass mineral wool slab with a water repellent additive. They are 455mm wide to suit standard vertical wall tie spacings, ensuring a closed joint with adjacent slabs. Typical construction The construction is based on 2 leaves of lightweight aggregate blocks with a minimum cavity width of 75mm leaf to leaf. A gypsumbased plasterboard is then dot-and-dabbed directly to the bare block face to provide the internal finish. The nominal specified weight of this gypsumbased plasterboard is 9.8 kg/m 2 m with a board thickness of 12.5mm or 15mm provided the nominal weight requirement is achieved. Installation Earthwool Acoustic Party Wall Slabs are installed as a partial-fill insulation positioned in the party wall cavity between wall ties. The slabs are held in place with retaining discs in the same manner as Earthwool DriTherm Cavity Slabs are when they are used to partially fill cavities in external masonry walls. All slabs should be tightly butted together with no open joints. The residual cavity between the foil-facing and the face of the opposite block must be a minimum of 40mm. Care should be taken to ensure that there are no mortar droppings bridging the cavity and the top of the slabs and wall ties are kept clean as installation proceeds. Cavity barriers The junction of the separating wall cavity and the external wall cavity must be closed to prevent flanking sound transmission. This is usually achieved by installing Earthwool DriTherm Cavity Wall Slab or Earthwool Cavity Barriers. Normal practice is to continue the installation of Earthwool Acoustic Party Wall Slab to the full height of the separating wall up to the underside of the roof. Performance Thermal performance Thermal performance typical U-values are shown in Table 87. Fire performance Earthwool Acoustic Party Wall Slab is classified as Euroclass A1 to BS EN ISO Acoustic performance Pre-completion testing is required for this construction. 656

14 Design details: Separating walls Separating wall/roof junction 2 layers 8kg/m 2 gypsum-based board Room-in-roof Glass wool closing junction between wall and roof eaves 100mm Earthwool Room-in-Roof Roll 32/37 Earthwool Acoustic Party Wall Slab Room-in-roof Typical specification Earthwool Acoustic Party Wall Slab...mm thick to be located in the cavity of all separating cavity walls. The residual cavity width to be 40mm. Insulation to be retained against one leaf of masonry by means of insulation retaining wall ties as manufactured by...* The wall ties to be Approved Document E tie type A. The first run of wall ties to be located at 600mm centres horizontally (at a level to be decided by the specifier). Ties thereafter to be at 450mm centres vertically and a maximum of 600mm horizontally. All work under construction must be protected overnight and during adverse weather conditions in accordance with BS 5628: Part 3: Alternatively, refer to NBS clause: F30/12,151. *Insert manufacturers details as appropriate Table 87: U-values of separating wall Product Thickness U-values (W/m 2 K) with additional airspace resistance* (m 2 K/W) (mm) Earthwool Acoustic Party Wall Slab * The additional airspace resistances are taken from Appendix A of BR 443 as follows: 0.31 for an access corridor with heat loss through the facing wall, plus floor or ceiling 0.43 for an access corridor with heat loss through the floor or ceiling 0.82 for a stairwell with the facing wall exposed 0.90 for a stairwell with the facing wall not exposed. There are specific additional requirements that need to be taken into to consideration when calculating the U-values for elements that are adjacent to unheated spaces. In multi storey dwellings such as flats and apartments the stairwells and access corridors are not regarded as part of the dwelling, and heat losses through the separating elements between the dwelling and the stairwell or access corridor are ignored if they are heated. If the stairwell or access corridor is unheated then the U-value of the walls between the dwelling and the unheated space can be modified by the inclusion of an additional amount of thermal resistance (R u ). The amount of additional thermal resistance that can be included in U-value calculations is dependent on whether or not the wall directly facing the dwelling wall is exposed or un-exposed, the influence of the floors in corridors is also taken into account. Standard default values can be taken from BR443 (Conventions for U-value Calculations) or SAP For situations not covered by default values, or where additional guidance is required contact our Technical Advisory Centre on

15 6.5.1 Design details: Separating walls Separating walls Existing masonry into separating wall Advantages Sw05 3 The independent steel studwork provides good acoustic isolation 3 50mm deep studs results in minimum loss of room space 3 Mineral wool in void absorbs sound and improves acoustic performance 3 Provides a high level of thermal separation between adjoining properties and unheated enclosed spaces, such as stairwells and corridors Existing separating wall 50mm Earthwool Acoustic Partition Roll or 50mm Earthwool Flexible Slab or 50mm Earthwool Universal Slab CS24 Independent I stud Two layers of 12.5mm plasterboard Products Earthwool Acoustic Partition Roll is made from glass mineral wool and formed into rolls which are lightweight, flexible, resilient and noncombustible. Earthwool Flexible Slab is a semi-rigid rock mineral wool slab. Earthwool Universal Slab CS24 is a semi-rigid glass mineral wool slab. Typical construction An existing brick or block wall with plaster finish on both sides that is intended to become a separating wall. An independent lining is added to one side of the wall using an independent I stud partition with 50mm Earthwool Acoustic Partition Roll between the studs and finished with two layers of 12.5mm plasterboard. This construction complies with Wall Treatment 1 in section 4 of Approved Document E. Pre-completion testing is required. Earthwool Flexible Slab and Earthwool Universal Slab CS24 are also suitable for use in this application. Installation Mark positions of the floor and ceiling of the floor U channels. Bed the U channels on two continuous beads of acoustic sealant and secure with nailable plugs at 600mm centres and 50mm from ends of channels. Cut the I studs to the floor to ceiling height, less 5mm. Place within the channels at 600mm centres. Install the Earthwool Acoustic Partition Roll, Earthwool Flexible Slabs or Earthwool Universal Slabs between the I studs, so there are no gaps. Fix the plasterboard layers with drywall screws at 300mm centres. The board joints should be staggered between layers. Seal all gaps at the perimeter of the plasterboard lining and where services, such as electrical sockets, penetrate the plasterboard, finish with acoustic sealant. Finish using standard drylining techniques. Performance Acoustic performance Earthwool Acoustic Partition Roll, Earthwool Flexible Slab and Earthwool Universal Slab have excellent sound absorption characteristics. For optimum performance, the insulation must be installed with no gaps. This solution is only suitable for refurbishment work and will require pre-completion testing to show compliance with Building Regulation requirements. Thermal performance Earthwool Flexible Slab has a thermal conductivity of or W/mK. Earthwool Universal Slab CS24 has a thermal conductivity of W/mK. Typical U-values are shown in Table

16 Design details: Separating walls Typical wall/floor section Typical specification Construct an independent framework using steel I studs, 10mm clear of the existing separating wall. Existing separating wall 50mm Earthwool Acoustic Partition Roll, 50mm Earthwool Flexible Slab or 50mm Earthwool Universal Slab CS24 Two layers of 12.5mm plasterboard Acoustic sealant Infill between the studs with 50mm Earthwool Acoustic Partition Roll*/Earthwool Flexible Slab*/Earthwool Universal Slab CS24*. Screw fix plasterboard to the steel framing as specified. Seal round the perimeter of the plasterboard with acoustic sealant. (*Delete as appropriate) Alternatively, consult the National Building Specifications (NBS) based on Standard Version K10/175A. It contains a set of proprietary clauses, which are edited versions written by Knauf Insulation. Fire performance Earthwool Acoustic Partition Roll, Earthwool Flexible Slab and Earthwool Universal Slab are classified as Euroclass A1 to BS EN ISO The use of a Class 0 plasterboard will meet the requirements of the Building Regulations for wall linings in all locations. Table 88: U-values for upgrading of 215mm sold brick separating wall Product Thickness Stud size U-values (W/m 2 K) with additional airspace resistance* (m 2 K/W) Product (mm) (mm) Earthwool Universal Slab CS24/Earthwool Flexible Slab * The additional airspace resistances are taken from Appendix A of BR 443 as follows: 0.31 for an access corridor with heat loss through the facing wall, plus floor or ceiling 0.43 for an access corridor with heat loss through the floor or ceiling 0.82 for a stairwell with the facing wall exposed 0.90 for a staircase with the facing wall not exposed. There are specific additional requirements that need to be taken into to consideration when calculating the U-values for elements that are adjacent to unheated spaces. In multi storey dwellings such as flats and apartments the stairwells and access corridors are not regarded as part of the dwelling, and heat losses through the separating elements between the dwelling and the stairwell or access corridor are ignored if they are heated. If the stairwell or access corridor is unheated then the U-value of the walls between the dwelling and the unheated space can be modified by the inclusion of an additional amount of thermal resistance (R u ). The amount of additional thermal resistance that can be included in U-value calculations is dependent on whether or not the wall directly facing the dwelling wall is exposed or un-exposed, the influence of the floors in corridors is also taken into account. Standard default values can be taken from BR443 (Conventions for U-value Calculations) or SAP For situations not covered by default values, or where additional guidance is required contact our Technical Advisory Centre on

17 Knauf Insulation Ltd PO Box 10 Stafford Road St Helens Merseyside WA10 3NS UK Tel: Fax: Ref: KB June 2010 Knauf Insulation Ltd Customer Service (Sales) Technical Advisory Centre Literature PO Box 10 Tel: Tel: Tel: Stafford Road Fax: Fax: Fax: St Helens Merseyside WA10 3NS