British Gypsum Guide to Timber Frame Construction. March 1998

Transcription

1 British Gypsum Guide to Timber Frame Construction March 1998

2 Timber frame construction has a centuries long tradition in the UK, however, over the last 80 years it has continuously evolved to meet the challenges of c1560 changing Regulations and expectations. Currently, the UK population of modern timber frame dwellings is around 1 million and the number is growing. Non housing c1860 applications such as hotels, nursing homes, schools, and community buildings, now account for over 30% of the UK Timber Frame Industry output British Gypsum products are widely specified within timber frame buildings to form internal elements. Applications include linings to external walls, partitions, ceilings, separating and compartment floors, cavity barriers and ceilings below roof spaces

3 Contents Introduction 4 Components 5 Applications 6 Performance 8 Performance tables 9 Design 15 Construction details 17 Board fixing on site 26 3

4 Introduction Timber framed construction is being increasingly adopted by a wide range of client groups because of its contribution to energy efficiency. Typical applications range from private dwellings through to hotels, nursing homes, and community buildings. Within timber frame buildings, British Gypsum products are extensively used to form the internal elements. They provide external wall linings, partitions, separating and compartment walls, ceiling linings, compartment floors, cavity barriers, and ceilings below roof spaces. Linings range from basic Gyproc Wallboard where economical space division is required, through to specialist boards such as Gyproc Wallboard Duplex, Moisture Resistant Board, Plank, Duraline, SoundBloc, Fireline, and Glasroc Multi-Board, chosen to achieve specified performance requirements. The lightweight nature of plasterboard and its speed of installation are ideally suited to timber frame building methods. This, coupled with completely dry construction techniques and the high standards of finishing that are possible, mean that British Gypsum products provide extremely cost-effective internal lining solutions. British Gypsum linings/elements conform to : BS 1230: Part 1: 1985 Specification for plasterboard excluding materials submitted to secondary operations. BBA Certificate No. 90/2541: Glasroc Multi-Board. BS 5234: Parts 1 & 2: 1993 Code of Practice: Internal non-loadbearing partitions. Limitations British Gypsum standard plasterboard linings are not generally suitable for use in areas subject to continuously damp or humid conditions. In such applications the designer should consider the use of specialist boards or treatments. For further details contact British Gypsum Technical Service Department on Seasoned timber with a moisture content not exceeding that recommended in BS 5268: Part 2: 1991 and BS 4978: 1988 should be used throughout. Handling and storage British Gypsum fully accepts its responsibilities as a supplier of building materials and systems as required by Section 6 of the Health and Safety at Work Act However, in designing and installing systems incorporating British Gypsum products, full consideration must be taken of the requirements of the following : Your attention is brought to the following publications which give approved guidance. 4 Manual Handling Guidance on Regulations ISBN Managing Construction for Health and Safety ACOP ISBN A Guide to Managing Health and Safety in Construction ISBN Designing for Health and Safety in Construction ISBN The Control of Substances Hazardous to Health in the Construction Industry ISBN Quality British Gypsum British Gypsum operates quality assurance procedures to BS EN ISO 9002, and maintains the quality and leading edge performance of its products and systems through an extensive and on going programme of research, development, and testing. This is supported by in house fire, acoustic, and system test facilities which are unique among building manufacturers, and match the best available anywhere in the U.K. Timber & Brick The Timber & Brick Quality Mark is a Quality Management and Product Conformity Scheme, which establishes a benchmark of good practice for designers and manufacturers of timber framed buildings. It is based upon the system requirements of ISO 9000, and the technical requirements of Building Regulations together with relevant British, European and Warrantors' Standards. There are two parts to the scheme covering both design and manufacture. Specifiers can now procure timber framed buildings safe in the knowledge that the companies they are approaching have all been through a rigorous third party certification process before being awarded their Certificate of Registration. In addition they are assured that on going surveillance is taking place to make sure that the high standards established at the initial registration stage are being maintained. The benefits of the Timber & Brick Quality Mark are only available from timber frame design and manufacturer members of Timber & Brick. A full list of members is available from The Timber & Brick Information Council on Manual Handling Operations Regulations Construction (Design and Management) Regulations Control of Substances Hazardous to Health Regulations 1988 (COSHH). 4

5 Components Gyproc and Glasroc boards description Gyproc and Glasroc boards data Table 1 Dimensions Type of board Thickness Width mm mm... Wallboard, Wallboard Duplex 9.5, 12.5, , 1200 Plank Moisture Resistant Board 9.5, 12.5, Duraline SoundBloc 12.5, Fireline 12.5, , 1200 Fireline Duplex Multi-Board 6, 10, Baseboard / Baseboard Duplex Lath 9.5, Gyproc Nails - 30, 40, 50, and 65mm, fixing boards to framing. Gyproc Drywall Screws - 32, 36, 42, 50, and 60mm, fixing boards to framing as an alternative to nail-fixing. Isowool General Purpose Roll (1000) or Isowool Acoustic Partition Roll (1200) - providing acoustic and thermal insulation in partitions, walls, roofs, and floors. Isowool Timber Frame Batts (1005) - providing thermal and acoustic insulation in external walls. Isowool Sound Deadening Floor Slabs (6405) - providing sound deadening in timber-base intermediate separating floors. Isowool Flanged Rolls (1012) and (1022) - paper-faced and aluminium-faced products respectively for specialist applications. Isowool Sleeved Cavity Fire Barrier - fire stopping. Gyproc Resilient Bar - for partially isolating the lining from the framing for improved sound insulation. Gyproc Sealant (optional) - sealing airpaths. Gyproc jointing materials - for a seamless finish, including: Joint Tape - perforated paper tape for joint reinforcement. Fibatape - self-adhesive glass fibre mesh tape. Joint Filler - tape bedding and filling joints. Easi-Fill - tape bedding, bulk filling, and finishing. Joint Cement - joint finishing (hand or mechanical). Glasroc Filler - bulk filling joints in Glasroc Multi-Board. Drywall Primer - priming the lining surface ready for decoration. Drywall Sealer - priming and sealing the lining surface to provide vapour control. Thistle Multi-Finish or Thistle Board Finish - providing a plaster finish to the decorative face as an alternative to jointing. Wallboard / Wallboard Duplex Standard board product suitable for direct decoration or gypsum plaster finish. Wallboard Duplex is backed with a vapour control membrane for use where a vapour control layer is specified. Plank 19mm thick version of Wallboard which provides additional mass Moisture Resistant Board Silicone treated core and water repellent green paper liner. Suitable as a base for ceramic tiling in wet use areas, and for external soffits in sheltered positions. Duraline Modified higher mass core with a heavy duty mustard coloured liner. Provides a high impact resistance wall and partition lining. SoundBloc High density core with a pale blue liner. Suitable for wall linings and partitions where greater levels of sound insulation are required. Fireline / Fireline Duplex Pink coloured liner. Glass fibre and other additives in the core to provide increased fire protection. Fireline Duplex is backed with a vapour control membrane for use where a vapour control layer is specified. Glasroc Multi Board Non combustible glass reinforced gypsum board. Combines excellent fire protection properties and high impact resistance. Ideal for curved linings. Baseboard / Baseboard Duplex Grey faced board suitable for lining timber joists, studs, and battens as a base for gypsum plasters. Baseboard Duplex is backed with a vapour control membrane for use where a vapour control layer is specified. Lath Grey faced ceiling board suitable for gypsum plaster application. 5

6 Applications Internal partitions and walls Timber stud partitions and walls are used in both new-build and general refurbishment. Timber stud separating and compartment walls are primarily specified as sound resisting walls in residential units such as flats and apartments to meet the sound insulation requirements of national Building Regulations. The partitions and walls are constructed from timber sections nail-fixed to provide a suitable single stud or twin stud framework. Gyproc or Glasroc boards are nail or screw-fixed to each side to form the lining. Isowool insulation will improve sound insulation if included in the stud cavity. Refer to Tables 2 and 3. External walls Gyproc plasterboards are used as the internal lining to structural timber frame walls. The external wall is based on a structural timber frame comprising factory-produced timber units to which sheathing board and a breather membrane is attached. The frame is tied to the external brick leaf using flexible wall ties. Alternative claddings, such as tile hanging and timber cladding, are fixed directly to the timber frame. Isowool glass mineral wool insulation is included in the stud cavity, and Gyproc plasterboard forms the internal lining. Refer to Table 4. Floors and ceilings Gyproc plasterboards are fixed to timber joists to form ceiling linings in both new-build and general refurbishment. They comprise one or two layers of board which are nail or screw-fixed to the timber joist supports. Isowool glass mineral wool insulation will improve the thermal and sound insulation. Compartment floors are primarily specified as sound resisting floors in residential units such as flats and apartments to meet the sound insulation requirements of national Building Regulations. They combine a plasterboard ceiling lining, Isowool insulation in the floor cavity, and a platform or Gyproc SI Floor to give the required airborne and impact sound performance. Refer to Tables 5 and 6. Roofs Gyproc plasterboard is used to line the underside of traditional or trussed roof rafters to provide a ceiling membrane with Isowool glass mineral wool insulation laid over the membrane to provide sound / thermal insulation. Gyproc Gyplyner or Gyproc MF Suspended Ceiling can be used where a reduced height ceiling is required. Refer to Table 7. Typical interiors Cavity barriers National Building Regulations require that concealed spaces in the structure or fabric of a building are sub-divided or sealed by means of cavity barriers or fire stopping. Suitable cavity barriers can be formed using Gyproc Fireline or Glasroc Multi-Board of appropriate thickness. Isowool Sleeved Cavity Fire Barrier can provide fire stopping. Refer to Table 8. 6

7 Energy efficient private housing Community housing for the elderly Period style private housing Private flats development Stone-faced environmentally conscious development 7

8 Performance Fire protection Plasterboard is designated a 'material of limited combustibility' within the Building Regulations The plasterboard surfaces achieve a Class 0 rating as a result of their performance when tested to BS 476: Parts 6 and 7. Glasroc Multi-Board is non-combustible when tested to BS 476: Part 4: Fire resistance The fire resistances given in Tables 2-8 are for imperforate constructions tested to BS 476: Part 8: 1972, or BS 476: Part 22: 1987, or are assessments based on these tests. Sound insulation The R w ratings given in Tables 2 8 are for imperforate constructions and have been calculated in accordance with BS 5821: Part 1: 1984, using measurements from laboratory tests to BS 2750: Part 3 : 1980, or estimates where direct test data is not available. Airtightness is essential for optimum sound insulation. While most junctions will be sealed by standard jointing materials, gaps at the base of the partition or lining, at the perimeter of the floor / ceiling, and other small airpaths, can be sealed using Gyproc Sealant. The laboratory sound insulation data quoted was measured in the absence of flanking transmission. The actual performance of the building element will generally be governed by flanking transmission. Water vapour control Where there is a requirement for a vapour control layer, Duplex grade boards should be specified as the face layer (i.e. the outer layer in double layer linings). The application of two coats of Gyproc Drywall Sealer to the face lining will also provide vapour control. Thermal properties Isowool glass mineral wool insulation is positioned between joists or wall studs to provide the required level of thermal insulation. The U values given in Table 4 for external wall constructions are based on a non-combustible glass mineral wool quilt being provided in the stud cavity. The use of 90mm Isowool Timber Frame Batts 1005 in conjunction with a standard 89mm stud framework can provide a U value down to 0.38W/m 2 K. The use of 140mm studs with the same thickness of Isowool 1005 can provide a U value down to 0.27W/m 2 K. Roof designs 8

9 Performance Table 2 Timber stud partitions and walls with Gyproc linings One layer of board each side One layer of board each Two layers of board each side Remedial treatment on one of timber studs at 600mm side of timber studs at of timber studs at 600mm side of existing plasterboard centres. 600mm centres with one layer centres. partition using 50 x 50mm fixed to Gyproc Resilient Bars timber battens at 400mm to one side plus 25mm centres with 50mm Isowool Isowool 1200 in the cavity between Gyproc Resilient Bar fixed horizontally and two layers of board. Detail Board type Board Nominal Approx. Fire Laboratory sound insulation Performance thickness partition weight resistance Hz substantiation thickness No insulation 25mm report Isowool 1200 ø mm mm kg/m 2 hours R w db R w db 1 Multi Board ½ 34 G Wallboard ½ A / Duraline ½ 36 Q Wallboard ½ A / SoundBloc ½ A / SoundBloc ½ A / Wallboard ½ 42 A / SoundBloc ½ A / Fireline A Wallboard A / SoundBloc A / SoundBloc A Fireline A Notes to Table 2 The fire resistance and sound insulation performances are for partitions and walls incorporating tapered edge boards with all joints taped and filled according to British Gypsum s recommendations. The quoted performances are achieved only if British Gypsum components are used throughout, and the Company's fixing recommendations are strictly observed. Any variations in the specifications should be checked with British Gypsum. All tests were carried out with boards nailed-fixed. Screw-fixing is an acceptable alternative - refer to board fixing on site, Table 12. Minimum dimensions of timber studs 75 x 38mm unless otherwise stated. Larger stud sizes will enhance performance. Loadbearing partitions at 100% load ratio, with minimum dimensions of timber studs nominal thickness 100 x 50mm. 50mm Isowool ø An equivalent sound insulation improvement can be achieved using 60mm Isowool

10 Table 3 Timber stud separating and compartment walls with Gyproc linings Separating / compartment walls 100% load ratio Compartment walls Two separate timber frames Two separate timber frames Two layers of board each side Two layers of board each side spaced 50mm apart, consisting consisting of 89 x 38mm timber of 75 x 38mm timber studs at of 75 x 38mm timber studs at of 89 x 38mm timber studs at studs at 600mm centres with 600mm centres with Gyproc 600mm centres with Gyproc 600mm centres with mid height mid height noggings. Two layers Resilient Bars fixed horizontally Resilient Bars fixed horizontally noggings. Two layers of board each of board each side. Min. 80mm to one side at 600mm centres. to both sides at 600mm centres. side. Min. 25mm Isowool 1200 Isowool 1000 between the studs Min. 50mm Isowool 1200 in Min. 50mm Isowool 1200 in the between the studs on one side. on one side. the cavity. cavity. 5 Separating / compartment wall in roof spaces Minimum 37mm timber roof trusses with additional framing to back board joints. One or two layers of board each side. Isowool insulation installed if required. Detail Board type Board Nominal Approx. Fire Laboratory sound insulation Performance thickness partition weight resistance Hz substantiation thickness report mm mm kg/m 2 hours R w db 5 Duraline (min) Q Wallboard 25 (2 x 12.5) 250 (min) A SoundBloc 25 (2 x 12.5) A SoundBloc 25 (2 x 12.5) A SoundBloc 30 (2 x 15) 263 (min) A Wallboard / Plank (min) A SoundBloc / Plank (min) A SoundBloc 30 (2 x 15) ½ 58 A SoundBloc / Plank ½ 58 A SoundBloc 30 (2 x 15) ½ 60 A SoundBloc / Plank ½ 60 A Notes to Table 3 The fire resistance and sound insulation performances are for walls incorporating tapered edge boards with all joints taped and filled according to British Gypsum s recommendations. The quoted performances are achieved only if British Gypsum components are used throughout, and the Company's fixing recommendations are strictly observed. Any variations in the specifications should be checked with British Gypsum. All tests were carried out with boards nailed-fixed. Screw-fixing is an acceptable alternative - refer to board fixing on site, Table 12. Detail 5 provides the 1 hour fire resistance between compartments as required by Building Regulations, subject to the suitability of the surrounding structure. The combination of ceiling and truss cladding is essential to meet the acoustic requirements of Building Regulations (see construction detail F). Where single layer Gyproc Duraline linings are used however, joints must be backed with timber. Alternatively, a min. 100mm wide strip of Duraline can be used. The actual fire and sound figures quoted are based on 100 x 35mm trusses at 600mm centres. The terminology for Separating and Compartment walls and floors follows the conventions established in the Approved Documents to the England and Wales Building Regulations. Part B refers to fire resisting constructions as "Compartment" walls, and Part E to sound resisting constructions as "Separating" walls. Please note, however, that not all walls designated as "Compartment" under Part B will be required to perform as "Separating" walls under Part E, although this is generally the case. If in doubt refer to the relevant Approved Document. Site sound test data is available on request. Contact British Gypsum Technical Service Department on

11 Table 4 Timber frame external walls mm 265mm 215mm Cladding of 100mm aggregate block with Cladding of 103mm facing brick ø Cladding comprising vertical tile hanging 20mm render tied with stainless steel wall ties tied with stainless steel wall ties across on treated 25mm battens fixed through across a nominal 50mm clear cavity through a nominal 50mm clear cavity through breather membrane and sheathing board breather membrane and sheathing board breather membrane and sheathing board to minimum 89 x 38mm timber studs to minimum 89 x 38mm timber studs to minimum 89 x 38mm timber studs at max 600mm centres. 90mm Isowool 1005 at max 600mm centres. at max 600mm centres. in stud cavity with internal linings as below. 90mm Isowool 1005 in stud cavity with 90mm Isowool 1005 in stud cavity with 100% load ratio. internal linings as below. 100% load ratio. internal linings as below. 100% load ratio. Detail Board Type Fire U value Estimated laboratory Performance resistance sound insulation substantiation hours W/m 2 K Hz, R w db report 1 One layer of 12.5mm Gyproc Wallboard Duplex ½ A One layer of 12.5mm Gyproc Wallboard Duplex ½ A One layer of 12.5mm Gyproc Wallboard Duplex ½ A Inner layer of 12.5mm Gyproc Wallboard and A outer layer of 12.5mm Gyproc Wallboard Duplex 2 Inner layer of 12.5mm Gyproc Wallboard and A outer layer of 12.5mm Gyproc Wallboard Duplex 3 Inner layer of 12.5mm Gyproc Wallboard and A outer layer of 12.5mm Gyproc Wallboard Duplex Notes to Table 4 The fire resistances quoted are for loadbearing walls tested with fire exposure to the internal face. Performances are for walls incorporating tapered edge boards with all joints taped and filled according to British Gypsum's recommendations. The quoted performances are achieved only if British Gypsum components are used throughout, and the Company's fixing recommendations are strictly observed. Any variations in the specifications should be checked with British Gypsum. All tests were carried out with boards nailed-fixed. Screw-fixing is an acceptable alternative - refer to board fixing on site, Table 12. Where higher standards of thermal insulation are required the use of 140mm studs with an equivalent thickness of Isowool 1005 will produce lower U values. Contact British Gypsum Technical Service Department on for guidance. U values are calculated by the proportional area method. The proportion of timber to mineral wool used in the calculations is 15% timber to 85% mineral wool. This allows for framing, lintels, cripple studs, etc., and is the figure used by T.R.A.D.A. for over 10 years. The Thermal Conductivity ( l )value used of 0.12W/mK for timber is based on that applicable to the Spruce / Pine / Fir groups from N. America and Europe used in timber frame structures. If standard wallboard is used in place of Duplex, a min. 500 gauge polyethylene film vapour control layer will be required directly behind the plasterboard, fixed to the face of the timber frame. The fire resistance performances quoted are independent of any contribution from the external construction. Conductivity ( λ ) of block taken as 0.51 W/mK (1400 kg/m 3 ) ø Conductivity ( λ ) of brick taken as 0.84 W/mK Other lightweight claddings, such as timber sidings, cementitious render or lath, etc., can be used and will offer the same performance. 11

12 Table 5 Timber joist floors with Gyproc ceiling linings Standard timber floor Minimum 30mm Gyproc Alpha Floor Gyproc Gyplyner Ceiling Gyproc Resilient Bars at with no insulation Screed on 1000 gauge polythene sheet framework to joists. 450mm centres to underside (taped at joints) laid on Expamet wire of joists. reinforced mesh with Gyproc Edge Strips to perimeter on any suitable floor deck. Detail Board type Flooring Joist Joist Fire Estimated laboratory Performance board centres width resistance sound insulation substantiation type (min.) Hz report Airborne Impact mm mm hours R w db L nw db 1 One layer of 12.5mm Gyproc Wallboard a ø ½ (modified) ø C One layer of 12.5mm Gyproc Wallboard a ½ (modified) ø V One layer of 12.5mm Gyproc Wallboard c ½ C One layer of 15mm Gyproc Wallboard a ½ C Two layers of 15mm Gyproc Wallboard c C Inner layer of 12.5mm Gyproc Fireline a C and outer layer of 15mm Gyproc Fireline 1 Two layers of 12.5mm Gyproc Fireline b C Inner layer of Gyproc Plank and a V outer layer of 12.5mm Gyproc Wallboard 4 Inner layer of Gyproc Plank and a C outer layer of 12.5mm Gyproc Wallboard 3 Inner layer of Gyproc Plank and a C outer layer of 12.5mm Gyproc Wallboard Two layers of 15mm Gyproc Fireline b ½ C Notes to Table 5 The fire resistance and sound insulation performances are for ceilings incorporating tapered edge boards with all joints taped and filled according to British Gypsum's recommendations. The quoted performances are achieved only if British Gypsum components are used throughout, and the Company's fixing recommendations are strictly observed. Any variations in the specifications should be checked with British Gypsum. All tests were carried out with boards nail fixed. Screw-fixing is an acceptable alternative - refer to Board fixing on site, Table 12. Where joist width is less than that stated, nominal 50 x 25mm timber battens should be screw fixed to the side of those joists where the ceiling boards butt in order to maintain an adequate bearing surface. Floor types a Any structurally suitable wood board flooring. b Wood board t & g flooring, not less than 15mm (finished) thickness. c Wood board t & g flooring, not less than 21mm (finished) thickness. No noggings. The acoustic ratings quoted above are based on 200mm deep joists and a walking surface of min. 9.6kg/m 3. ø 15 : 15 : 30 in accordance with Approved Document. If floor type c is used the fire resistance increases to a full ½ hour. 12

13 Table 6 Compartment / separating floors Platform floor. Platform floor. Gyproc Gyplyner Gyproc SI Floor with Gyproc Plank 100mm Isowool 1000 or Gyproc MF Suspended Ceiling hung on SIF Channels. between the joists. underneath timber joists to give a 277mm cavity, 100mm Isowool 1000 in cavity. with 80mm Isowool 1000 between joists. Gyproc Resilient Bars at 450mm centres Gyproc SI Floor with Gyproc Plank on Separating sub joist floor comprising Minimum 30mm Alpha Gyproc Floor Screed on SIF Channels. 100mm Isowool 1000 in cavity. platform floor gauge polythene sheet (taped at joints) Gyproc Gyplyner Ceiling framework to joists. 100mm Isowool 1000 in cavity laid on Expamet wire reinforced mesh with Gyproc Edge Strips to perimeter on any suitable floor deck. 100mm Isowool 1000 in cavity Gyproc Gyplyner Ceiling framework to joists. Detail Board type Flooring Joist Joist Fire Laboratory sound insulation Performance board centres width resistance Hz substantiation type (min.) Airborne Impact report mm mm hours R w db L nw db 6 One layer of 15mm Gyproc Fireline a V Two layers of 12.5mm Gyproc SoundBloc b C Gyproc Plank with outer layer of c C mm Gyproc SoundBloc 3 One layer of Gyproc Plank and b C one layer of 12.5mm Gyproc SoundBloc 4 One layer of Gyproc Plank and b C one layer of 12.5mm Gyproc SoundBloc 2 Two layers of 12.5mm Gyproc SoundBloc c C Two layers of 15mm Gyproc SoundBloc c ø 48 C Two layers of 15mm Gyproc Fireline b ½ C Notes to Table 6 The fire resistance and sound insulation performances are for ceilings incorporating tapered edge boards with all joints taped and filled according to British Gypsum's recommendations. The quoted performances are achieved only if British Gypsum components are used throughout, and the Company's fixing recommendations are strictly observed. Any variations in the specifications should be checked with British Gypsum. All tests were carried out with boards nailed-fixed. Screw-fixing is an acceptable alternative - refer to board fixing on site, Table 12. Where joist width is less than that stated, nominal 50 x 25mm timber battens should be screw fixed to the side of those joists where the ceiling boards butt in order to maintain an adequate bearing surface. The terminology for Separating and Compartment walls and floors follows the conventions established in the Approved Documents to the England and Wales Building Regulations. Part B refers to fire resisting constructions as "Compartment" walls, and Part E to sound resisting construction as "Separating" walls. Please note, however, that not all walls designated as "Compartment" under Part B will be required to perform as "Separating" walls under Part E, although this is generally the case. If in doubt refer to the relevant Approved Document. Floor types a Any structurally suitable wood board flooring. b Softwood floor boarding, not less than 21mm (finished) thickness. c Walking surface of 18mm t & g wood board flooring, spot bonded with Gyproc Sealant at 300mm centres to a substrate of Gyproc Plank laid on 25mm Isowool 6405 (64kg/m 3 ) laid on minimum 12mm wood based sheet sub-deck nailed to the joists. Site sound insulation figures are available on request. ø Under estimate of airborne sound insulation performance due to laboratory constraints. Normal fixing centres for MF5s and MF7s (450 and 1200mm respectively). The example shown, using a combination of Gyproc Alpha Floor Screed and timber floor construction, has been the subject of acoustic testing and fire resistance assessment. Before specifying this construction, advice should be sought from a suitably qualified timber or structural engineer to determine the appropriate size, span, and spacing of joists able to withstand all imposed loads, including that of the floor screed. At 30mm thickness, Gyproc Alpha Floor Screed has a mass of up to 63kg/m 2. The 30N/mm 2 grade of Gyproc Alpha Floor Screed has a flexural strength of at least 6N/mm 2. 13

14 Table 7 Ceilings below roof spaces Timber joists or bottom chord of trusses with suitable timber noggings between joists to Gyproc Gyplyner or MF Suspended support board edges. Insulation laid between joists. Ceiling hung from joists. Insulation laid over grid. Detail Board type Joist / truss Min. joist / truss Insulation Insulation Fire Performance centres width type thickness resistance substantiation mm mm mm hours report 1 One layer 12.5mm Glasroc Multi Board Isowool ½ G Two layers 12.5mm Gyproc Wallboard Isowool ½ C One layer 12.5mm Gyproc Fireline Isowool ½ C Two layers 12.5mm Gyproc Wallboard Isowool ½ C Two layers 10mm Glasroc Multi Board Isowool G Two layers 12.5mm Gyproc Fireline Rock mineral C wool (24kg/m 3 ) 4 Two layers 12.5mm Gyproc Fireline Rock mineral 30 1 C wool (45kg/m 3 ) Notes to Table 7 The fire resistance performances are for imperforate ceilings incorporating tapered edge boards with all joints taped and filled according to British Gypsum's recommendations. The quoted performances are achieved only if British Gypsum components are used throughout, and the Company's fixing recommendations are strictly observed. Any variations in the specifications should be checked with British Gypsum. All tests were carried out with boards nail fixed. Screw-fixing is an acceptable alternative - refer to Board fixing on site, Table 12. Where timber bearing width is 35mm or less than the minimum stated, nominal 50 x 25mm timber battens should be fixed to the side of timber supports where the ceiling boards butt in order to maintain an adequate bearing surface (refer to Board fixing on site, Fig 1). Table 8 Cavity barriers Detail Construction Fire resistance Performance Integrity : Insulation substantiation minutes report 10mm Glasroc Multi Board fixed to one side of a timber stud framework G or trusses at maximum 600mm centres using Gyproc Nails or Screws at 230mm centres. Fire stopping to the perimeter as necessary. As above but with 12.5mm Gyproc Fireline E Isowool Sleeved Cavity Fire Barrier sealing the cavity between the outer brick wall E and the internal timber frame leaf. Notes to Table 8 The fire resistances are for barriers with all joints taped and filled according to British Gypsum's recommendations. The quoted performances are achieved only if British Gypsum components are used throughout, and the Company's fixing recommendations are strictly observed. Any variations in the specifications should be checked with British Gypsum. Joints between sleeved cavity barriers must be compressed in accordance with Isowool recommendations in order to achieve 30 minutes insulation. 14

15 Specification clauses For details of Specification Clauses contact British Gypsum Technical Service Department on Design When designing timber frame buildings, the designer should take account of relevant British Standards, Documents, and associated literature. General guidance can be obtained by contacting the Timber and Brick Information Council on For further guidance on British Gypsum products and systems, refer to The White Book, or contact British Gypsum Technical Service Department on General considerations Ensure that fixing recommendations are followed for the specific board to be installed refer to current British Gypsum literature. Consider using Gyproc Drywall Screws to eliminate the risk of nail popping. Consider using Gyproc Duplex grade board where there is a need for vapour control. Site conditions must be suitable for the installation of plasterboard, e.g. building sealed against the elements, wet trades finished (floor screeds etc.). Timber must be aligned and levelled, and should satisfy the requirements of BS 5268: Part 2: When textured coatings are specified the manufacturer's recommendations must be followed. Ensure that the floor construction is suitable to support any imposed loads, such as the inclusion of thermal insulation in the cavity. If ceiling heating is specified for use with plasterboard, the manufacturer's recommendations must be followed. Ensure that cavity barriers are installed where required in order to satisfy national Building Regulations, particularly in perimeter walls in roof spaces and at roof / separating wall junctions. Racking resistance Plasterboard products contribute to the racking resistance of timber frames in accordance with BS 5268: Section 6.1: 1988 Strength and robustness The dimensions and assembly of timber supports should be sufficient to allow positive fixing of boards without bounce or undue deflection because of nailing, screwing, or other applied force. When the above fixing conditions cannot be met, a timber batten should be securely fixed to the side of the timber support to increase the bearing surface. Where boards are fixed at maximum centres in adverse conditions, the standard of lining can be affected. Adverse conditions can generally be described as conditions where high humidity occurs, principally in the cold, damp autumn / winter period. They also refer to buildings under construction during this period where both the structure and wet applications such as plastering and screeding are subject to slow drying conditions. In small flat roof areas, where a polythene vapour control layer is included in the ceiling construction, condensation can form on the polythene surface. This can result in plasterboard becoming unduly damp, and affecting the standard of acceptability of the lining, and any applied plaster or textured coating. Sound insulation In designing for sound insulation it is important to set targets which are correct in terms of the uses of spaces separated by partitions and walls. The table below can be used for guidance. R w Table 9 Degree of acoustic privacy Speech level db Normal speech can be easily overheard 30 db Loud speech can be heard clearly 35 db Loud speech can be distinguished under normal conditions 40 db Loud speech can be heard but not distinguished 45 db Loud speech can be heard faintly but not distinguished > 50 db Loud speech or shouting can only be heard with great difficulty... Service penetrations Suitable detailing will be required at service penetrations if specified levels of fire resistance and sound insulation are to be achieved. Refer to construction details F and M, which have been shown by tests to maintain integrity. Room in a roof Where Gyproc plasterboard is used to line a room in a roof for the purposes of fire resistance, a surface sloping more than 70º from vertical is treated as a ceiling, and less than 70º from vertical as a wall lining. Timber noggings Perimeter support, using either min. 38 x 38mm timber noggings or plasterboard clips, may be required between ceiling joists to support board edges. The provision of noggings depends on the thickness of boards used, and the spacing of timber joists. Timber noggings / clips should always be provided at the room perimeter with the exception that they are not required when using 15mm Gyproc Wallboard. Nail popping Loosening of nails in timber can occur through timber shrinkage, or as a result of fixing boards to misaligned or twisted framing. To reduce the risk, boards should be fixed tight to framing members. Where the risk of nail popping is unacceptable, consideration should be given to fixing using Gyproc Drywall Screws. For further advice contact British Gypsum Technical Service department on

16 Partition junctions Where partition junctions occur, additional studs can be specified within the factory produced wall panels, and can be incorporated either during manufacture or on site. Alternatively, a suitable ladder frame can be installed between vertical studs during site construction, with horizontal members at 600mm centres (see Construction detail W for typical example). Services Electrical and other small service runs can be routed within the timber stud / floor cavity. The installation of electrical services should be carried out to BS 7671, following the recommendations of the Institution of Electrical Engineers. Concealed cables may need earthed metallic covering, or be enclosed in earthed conduit, trunking, or ducting to satisfy BS Cables located within thermal insulation may need to be up rated to counter the effect of overheating (IEE Regulations refer). Fixtures The selection of the most appropriate fixing depends on the weight of fixtures to be installed, the particular Gyproc system used, and whether the fixing has to bridge a cavity. Table 10 gives general guidance. Table 10 Fixtures to plasterboard Fixture Example Solution... Heavy Lavatory cisterns; Framing to be incorporated in wash hand basins; partitions. In lining systems storage heating the fixing to be made back to the units; structure using a proprietary central heating fixing. The cavity may need to be boilers. blocked.... Medium to Wall cupboards; Mushroom plugs, proprietary heavyweight radiators. anchors, cavity fixings.... Medium Floor cupboards; Proprietary anchors, cavity light fittings. fixings.... Lightweight Pictures. Steel pin and hook.... Note : Detailed recommendations and guidance on suitable proprietary fixings are given in the British Gypsum White Book, or Technical Information leaflet 'Fixtures to plasterboard', and in the Timber and Brick Information Council publications 'Living in a Timber and Brick Home', and the Timber and Brick Homes Handbook. Ceramic tiling Ceramic tiles up to 12.5mm thick with a maximum weight of 32kg/m 2 can be applied using thin bed adhesives (usually 3mm thick). Stud support centres should be closed down to 400mm, or alternatively, timber noggings (50 x 38mm) should be installed horizontally between studs at 600mm centres within the area to be tiled. Gyproc Moisture Resistant Board should be specified as the lining. For small areas such as splashbacks, however, standard wallboard can be used, provided that the surface is protected by applying two coats of Gyproc Drywall Sealer prior to tiling. Finishing Plasterboards (excluding Moisture Resistant Board) Tapered edge boards are used for the vast majority of dry lining work. For jointing, Gyproc Joint Tape is used to reinforce board joints to minimise any risk of cracking. Gyproc Fibatape provides an alternative method but is not a direct substitute in its resistance to cracking. Tape is bedded, (or in the case of Fibatape, which is self adhesive, stuck over the joint), and the joint filled, using Gyproc Joint Filler or Gyproc Easi Fill. Gyproc Joint Cement is used as the finishing compound. If Gyproc Easi Fill is used, it can be also be used for finishing. Once the joint treatment is set and dry, the entire plasterboard surface is treated with one coat of Gyproc Drywall Primer. This primes the board ready for direct decoration, and allows wall coverings to be wet stripped in the future. Where vapour control is specified, two coats of Gyproc Drywall Sealer are applied to prime and seal the board surface. Drywall Sealer, however, should not be used in conjunction with vinyl or other low permeability wall coverings. A gypsum plaster finish can be specified as an alternative to jointing and primer application. Thistle Multi Finish or Thistle Board Finish plaster can be applied to the decorative face of the board to a nominal 2mm thickness after joint treatment. Gyproc Moisture Resistant Board Gyproc Moisture Resistant Board can be used as a ceramic tile backer board, and is available with tapered or square edges. This product can only be plastered provided the surface is pre treated with a proprietary PVAC bonding agent applied in accordance with the manufacturer's instructions. Gyproc Easi Fill is recommended for jointing. Glasroc Multi Board Glasroc Multi Board is jointed using Glasroc Filler as a taped or tapeless joining method, or Gyproc Joint Cement where the joint is to be reinforced with Gyproc Joint Tape. Textured finishes If a textured finish is to be applied, nail heads should be spotted using Gyproc jointing material. Gyproc Drywall Primer should be applied as soon as possible after board fixing. Joint treatment and texturing should be carried out in accordance with the texture manufacturer's instructions. Ornate / decorative features Other decorative products from British Gypsum and Artex-Blue Hawk include Gyproc Cove and Cornice profiles, Gyproc Styletrims, Artex Ceiling Roses and Artex Dado Panels. 16

17 Construction key drawings The construction details that follow are generic and represent good practice. Individual practitioners will have their own preferred details, but these should follow the principles set out herein. Particular attention is drawn to the junctions between external walls and separating / compartment floors, where the principles of separation to avoid flanking sound transmission must be followed if the quoted acoustic performance of individual elements is to be achieved. The terminology for Separating and Compartment walls and floors follows the conventions established in the Approved Documents to the England and Wales Building Regulations. Part B refers to fire resisting constructions as "Compartment" walls, and Part E to sound resisting construction as "Separating" walls. Please note, however, that not all walls designated as "Compartment" under Part B will be required to perform as "Separating" walls under Part E, although this is generally the case. If in doubt refer to the relevant Approved Document. Key Drawings - Housing Cross section Longitudinal section Plan Key Drawings - Flats / Commercial buildings Cross section Longitudinal section 17

18 Construction individual details A C B D 18

19 Construction individual details E F G H 19

20 Construction individual details J K L M 20

21 Construction individual details N Q P R 21

22 Construction individual details S U T V 22

23 Construction individual details W Y X Z 23

24

25 List of details by reference letter Detail Reference Title A B C D E F G H Typical Eaves detail External wall/ground floor Non loadbearing partition/upper floor ceiling Non loadbearing partition/ground floor External wall to verge Compartment (Separating) wall to underside of tiled roof External wall/timber joist floor Compartment (Separating) wall junction with timber joist floor. (Small electrical outlet box detail also shown) J K L M N P Q R S T U V W X Y Z External wall/compartment (Separating) floor with typical window head External wall with typical window cill Compartment (Separating) floor junction with Compartment (Separating) wall Compartment (Separating) wall with larger electrical outlet box Non-loadbearing partition on Compartment (Separating) floor Compartment (Separating) floor junction with loadbearing partition under Compartment (Separating) floor with loadbearing partition under and non loadbearing partition over Compartment (Separating) floor junction with loadbearing partition top and bottom Non loadbearing partition on timber joist floor Loadbearing partition/ground floor Loadbearing or non-loadbearing partition under timber joist floor Compartment (Separating) wall/ground floor Compartment (Separating) wall junction with internal partition on plan External wall with internal partition junction and typical door jamb on plan Compartment (Separating) wall junction with external wall showing typical window jamb on plan External wall at corner showing typical window jamb on plan. Note These details relate to buildings constructed in England & Wales. Some minor modifications will be required to comply with the Scottish and Northern Ireland Building Regulations. 24

26

27 Annotation notes to Construction details 1. Brickwork. 2. External wall cavity. 3. Stainless steel wall ties. 4. Breather membrane. 5. Wood based sheathing board. 6. Structural timber frame. 7. Vapour control layer (minimum 500 gauge or Gyproc Wallboard Duplex). 8. Gyproc Wallboard 12.5mm thick. 9. Gyproc Plank (19mm thick). 10. Gyproc SoundBloc 12.5mm thick. 11. Mineral wool insulation minimum 10kg/m 3 (Isowool Timber Frame Batts ) mm glass wool kg/m 3 (Isowool Sound Deadening Floor Slabs 25mm thick ) mm mineral wool minimum 10kg/m 3 (Isowool General Purpose Roll ). 14. Isowool Sleeved Cavity Fire Barrier 15. Fire stop. (50mm thick wire reinforced rock mineral wool). 16. Wood based sheet walking surface (minimum 18mm thick). 17. Walking surface spot bonded to Gyproc Plank with Gyproc Sealant at 300mm centres. 18. Wood based sheet sub-deck (minimum 12mm thick). 19. Isowool General Purpose Roll (1000) 50mm thick in one leaf of separating wall. Alternatively, 25mm of mineral wool (paper faced on one side) may be suspended in the cavity for the full storey height. 20. Resilient upstand (strips of EPS or Extruded Polystyrene). 21. Gap: A 3mm gap must be retained between the wall lining, skirting and walking surface to maintain the correct isolation so as to prevent flanking transmission of impact sound. This may, if desired, be pugged with loose mineral wool or sealed with polysulphide mastic m x 3m metal straps at minimum 1200mm centres located just above or below floor level. 23. Damp proof course. 24. Damp proof membrane. 25. Differential movement gap. Minimum gaps to be as in the table below. Differential movement gap table Suspended timber ground floor Other ground floor when panels are supported construction on ground floor joists or perimeter joists... Allowances for : ground floor openings 5mm 3mm first floor openings 12mm 9mm second floor openings 18mm 15mm Eaves and verges Add 3mm to the allowance for openings on the uppermost floor Roof space ventilation. 27. Maximum 65mm long annular ring shank nails or screws. 28. Additional layer of Gyproc Wallboard 12.5mm thick required in buildings of 1hr fire resistance (for example flats 3 storeys and over). 29. Window frame (typical). 30. Door frame (typical). 31. Small electrical outlet box viz. switch or 13amp socket. 32. Larger electrical outlet box for example, cooker point. 33. Minimum 38mm thick s.w. nogging. 34. Electricity cable tight fit through hole in nogging. 35. Proprietary mild steel lintel to support outer leaf of brickwork. 36. Weephole in perpend joint, min. two per opening and at 900mm max. centres. 37. Flexible and compressible mastic sealant. 38. Semi rigid slab insulation. 39. Trussed rafter. 40. Gable ladder. 25

28 Board fixing on site The following gives an appreciation of installation procedures. For full fixing details contact British Gypsum Technical Service Department on Timber frame external walls Factory produced timber wall panels of the required dimension are installed to form the structural building frame. Studs are uniformly spaced at max. 600mm intervals, with additional framing installed as required to support heavy fixtures or adjoining partitions. Isowool Timber Frame Batts 1005 are fitted into the stud cavity. Alternatively, if an Isowool roll is used, it should be suspended between studs. Gyproc Wallboard Duplex is nail fixed to all framing members at 150mm centres, or screw fixed at 300mm centres, to form the lining. Where door or window openings occur, lintels and additional vertical studs are normally incorporated within wall units during factory construction. Timber stud partitions and walls Timber of the required dimensions is installed to the perimeter, abutments, and to frame any openings. Additional framing is installed as required to support heavy fixtures. Isowool insulation is suspended in the cavity where required. Where Gyproc Resilient Bars are specified, these are fixed across studs, at 600mm centres, with one fixing per stud position. Gyproc plasterboard is nail fixed to all framing members at 150mm centres, or screw fixed at 300mm centres, to form the lining. Additional boarding is nail or screw fixed as specified. At door openings, full height studs are located both sides of the opening together with a timber head piece. Door facings are then fixed to the timber ground. Run of ceiling Lath and Baseboard Boards are installed as for Wallboards, except that the rounded edge of Gyproc Lath and the square edge of Gyproc Baseboard only require to be supported by noggings at the perimeter. Services Electrical and other services are installed within the stud or floor cavity prior to fitting insulation. Timber noggings are installed to support recessed switch boxes / socket outlets. Additional linings may be required to maintain fire resistance and acoustic performance. Table 11 Provision of timber noggings in floors Board thickness Max. joist centres with noggings without noggings mm mm mm Noggings are recommended for Fireline board and Duplex grade boards, regardless of joist spacing, to ensure that fire and/or vapour control integrity is maintained. When fixing Gyproc Lath or Baseboard, noggings are not required in the field of the boards. Fig 1 Fixing boards to trussed rafters Timber joist ceilings and compartment floors Run of ceiling Wallboard linings Boards should be fixed to form the ceiling with the long edges at right angles to the joists. Cut ends must be located over a joist or timber nogging support. Unless 15mm Gyproc Wallboard is used, timber noggings should be provided between joists at the perimeter to support board edges in the field of the boards (see Table 11). Boards are fixed using Gyproc Nails inserted at 150mm centres, or Gyproc Drywall Screws inserted at 230mm centres. For double layer ceilings, noggings are set out to suit the second layer to provide fixing and support for board edges. All joints are staggered in relation to the first layer. 35mm 25mm In trussed rafter situations, it is possible that the bottom chord of the truss can be as little as 35mm thick. Where board ends butt and fire resistance is a requirement, it is important that additional timber is planted on the side of the truss to give an adequate bearing surface, (see Fig 1). 26

29 Nail / screw fixing Table 12 gives the recommended length of fixings. Where there is a risk of nail popping the use of Gyproc Drywall Screws should be considered. Fixing tolerances are given in Fig 2. Table 12 Fixing plasterboard to timber supports Plasterboard Gyproc Drywall Screws Gyproc Nails to fix thickness to fix plasterboard for plasterboard for direct direct decoration decoration or plastering to timber mm mm mm over over over over Note: Nail fixing to timber supports. Drive the nails into the timber straight not skewed and not closer than 6mm from the timber edge (see Fig 2). If the timber support has insufficient bearing surface, fix a further timber support to it, or, in the case of joists and trusses, consider using suitable counter battens. Drive the nails firmly home without fracturing the paper surface, but leaving a shallow depression to facilitate spotting. 5.65m high structural elements Fig 2 Fixing tolerances A 6mm min Boards should be lightly butted with a max. separation of 3mm. Where a cut edge occurs dimension A is 13mm min; where a bound edge occurs dimension A is 10mm min. Built-up elements 27

30 Prefabrication Structural elements Internal structure Typical Dormer window 28

31 Acknowledgements British Gypsum would like to thank the Timber and Brick Information Council, together with Laing Homes, for their assistance and support in preparation of this brochure. The Timber and Brick Information Council is the recognised trade association representing manufacturers and designers of timber frame buildings in England and Wales. Technical support For technical guidance or specification support on British Gypsum products, contact : For technical information and guidance on structural elements, construction details, cladding options, and the Timber and Brick Q mark, contact : British Gypsum Limited Technical Service Department East Leake Loughborough Leics. LE12 6JT The Timber and Brick Information Council Gable House 40 High Street Rickmansworth Herts. WD3 1ES Tel : Fax : Tel : Fax : [email protected] 29

32 British Gypsum... UK market leader in gypsum plaster and plasterboard systems, British Gypsum markets its products under the Gyproc, Glasroc, Carlite, Thistle and Isowool brand names. Isowool is a registered trade name of British Gypsum Isover Ltd. British Gypsum operates quality assurance procedures to BS EN ISO 9002 and maintains the quality and leading edge performance of its products and systems through an extensive and on-going programme of research, development and testing, supported by in-house fire, acoustic and system test facilities which are unique amongst building product manufacturers and match the best available anywhere in the UK. British Gypsum quality does not stop at the products themselves. CAD and technical support for specifiers; comprehensive on-site support and off-site training through three dedicated product training centres at East Leake near Nottingham, Kirkby Thore in Cumbria, and Erith in Kent, and ex-stock or next day availability through more than 4000 builder's merchants nationwide are just a part of a customer support package that has, for many years, set British Gypsum apart in the market place. British Gypsum further benefits from being a member of Europe's leading gypsum company, BPB plc, which has interests in a wide range of associated building products and provides an extensive pool of knowledge and experience to the benefit of all its member companies. Written enquiries Technical service Price Written enquiries should be addressed to:- British Gypsum Limited British Gypsum technical staff are available for discussion and to render technical advice when the Company's products are being specified or used. These services are available nationally through the numbers listed below. Technical Service Dept. East Leake Telephone Loughborough Leicestershire LE12 6JT Fax British Gypsum March 1998 TFC V1... A BPB group company Q.5978