timber frame

March 1998

British Gypsum Guide toTimber Frame Construction

Timber Frame Construction

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

changing Regulations and

expectations. Currently, the UK

population of modern timber

frame dwellings is around

1 million and the number is

growing. Non–housing

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.

2

c1560

c1860

1974

1995


Contents

Introduction 4

Components 5

Applications 6

Performance 8

Performance tables 9

Design 15

Construction details 17

Board fixing on site 26

3


Your attention is brought to the following publications whichgive approved guidance.

4 Manual Handling Guidance on RegulationsISBN 0 11 886335 5.

5 Managing Construction for Health and Safety ACOPISBN 0 7 7176 0792 5.

6 A Guide to Managing Health and Safety in ConstructionISBN 0 7176 0755 0.

7 Designing for Health and Safety in ConstructionISBN 0 7176 0807 7.

8 The Control of Substances Hazardous to Health in theConstruction Industry ISBN 0 11 885526 3.

QualityBritish GypsumBritish Gypsum operates quality assurance procedures toBS EN ISO 9002, and maintains the quality and leading edgeperformance of its products and systems through anextensive and on–going programme of research,development, and testing. This is supported by in–house fire,acoustic, and system test facilities which are unique amongbuilding manufacturers, and match the best availableanywhere in the U.K.

Timber & BrickThe Timber & Brick Quality Mark is a Quality Managementand Product Conformity Scheme, which establishes abenchmark of good practice for designers and manufacturersof timber framed buildings. It is based upon the systemrequirements of ISO 9000, and the technical requirements ofBuilding Regulations together with relevant British, Europeanand Warrantors' Standards. There are two parts to thescheme covering both design and manufacture.

Specifiers can now procure timber framed buildings safe inthe knowledge that the companies they are approachinghave all been through a rigorous third party certificationprocess before being awarded their Certificate ofRegistration. In addition they are assured that on–goingsurveillance is taking place to make sure that the highstandards established at the initial registration stage arebeing maintained.

The benefits of the Timber & Brick Quality Mark are onlyavailable from timber frame design and manufacturermembers of Timber & Brick. A full list of members is availablefrom The Timber & Brick Information Council on01923 778136

Introduction

Timber framed construction is being increasingly adopted bya wide range of client groups because of its contribution toenergy efficiency. Typical applications range from privatedwellings through to hotels, nursing homes, and communitybuildings.

Within timber frame buildings, British Gypsum products areextensively used to form the internal elements. They provideexternal wall linings, partitions, separating andcompartment walls, ceiling linings, compartment floors,cavity barriers, and ceilings below roof spaces. Linings rangefrom basic Gyproc Wallboard where economical spacedivision is required, through to specialist boards such asGyproc 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 ofinstallation are ideally suited to timber frame buildingmethods. This, coupled with completely dry constructiontechniques and the high standards of finishing that arepossible, mean that British Gypsum products provideextremely cost-effective internal lining solutions.

British Gypsum linings/elements conform to :BS 1230: Part 1: 1985 Specification for plasterboard excludingmaterials submitted to secondary operations.BBA Certificate No. 90/2541: Glasroc Multi-Board.BS 5234: Parts 1 & 2: 1993 Code of Practice: Internalnon-loadbearing partitions.

LimitationsBritish Gypsum standard plasterboard linings are notgenerally suitable for use in areas subject to continuouslydamp or humid conditions. In such applications the designershould consider the use of specialist boards or treatments. Forfurther details contact British Gypsum Technical ServiceDepartment on 0990 456123.

Seasoned timber with a moisture content not exceeding thatrecommended in BS 5268: Part 2: 1991 and BS 4978: 1988should be used throughout.

Handling and storageBritish Gypsum fully accepts its responsibilities as a supplier ofbuilding materials and systems as required by Section 6 of theHealth and Safety at Work Act 1974. However, in designingand installing systems incorporating British Gypsum products,full consideration must be taken of the requirements of thefollowing :

1 Manual Handling Operations Regulations 1992.2 Construction (Design and Management) Regulations 1994.3 Control of Substances Hazardous to Health Regulations

1988 (COSHH).

4


5

Components

Gyproc and Glasroc boards – data

Table 1 Dimensions

Type of board Thickness Widthmm mm

.....................................................................................

Wallboard, Wallboard Duplex 9.5, 12.5, 15 900, 1200

Plank 19 600

Moisture Resistant Board 9.5, 12.5, 15 1200

Duraline 12.5 1200

SoundBloc 12.5, 15 1200

Fireline 12.5, 15 900, 1200

Fireline Duplex 12.5 1200

Multi-Board 6, 10, 12.5 1200

Baseboard / Baseboard Duplex 9.5 900

Lath 9.5, 12.5 400.....................................................................................

Gyproc and Glasroc boards – description

Wallboard / Wallboard DuplexStandard board product suitable for directdecoration or gypsum plaster finish.

Wallboard Duplex is backed with a vapour controlmembrane for use where a vapour control layer isspecified.

Plank19mm thick version of Wallboard which providesadditional mass

Moisture Resistant BoardSilicone treated core and water repellent greenpaper liner. Suitable as a base for ceramic tiling inwet–use areas, and for external soffits in shelteredpositions.

DuralineModified higher mass core with a heavy dutymustard coloured liner. Provides a high impactresistance wall and partition lining.

SoundBlocHigh density core with a pale blue liner. Suitable forwall linings and partitions where greater levels ofsound insulation are required.

Fireline / Fireline DuplexPink coloured liner. Glass fibre and other additives inthe core to provide increased fire protection.

Fireline Duplex is backed with a vapour controlmembrane for use where a vapour control layer isspecified.

Glasroc Multi–BoardNon–combustible glass reinforced gypsum board.Combines excellent fire protection properties andhigh impact resistance. Ideal for curved linings.

Baseboard / Baseboard DuplexGrey faced board suitable for lining timber joists,studs, and battens as a base for gypsum plasters.

Baseboard Duplex is backed with a vapour controlmembrane for use where a vapour control layer isspecified.

LathGrey faced ceiling board suitable for gypsum plasterapplication.

Gyproc Nails - 30, 40, 50, and 65mm, fixing boards to framing.

Gyproc Drywall Screws - 32, 36, 42, 50, and 60mm, fixingboards to framing as an alternative to nail-fixing.

Isowool General Purpose Roll (1000) orIsowool Acoustic Partition Roll (1200) - providing acousticand thermal insulation in partitions, walls, roofs, and floors.

Isowool Timber Frame Batts (1005) - providing thermaland 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 fromthe 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 aplaster finish to the decorative face as an alternative to jointing.


Applications

Internal partitions and wallsTimber 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 wallsGyproc 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 ceilingsGyproc 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.

RoofsGyproc 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.

Cavity barriersNational 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

Typical interiors


7

Energy efficient private housing

Period style private housing

Community housing for the elderly

Private flats development

Stone-faced environmentally conscious development


Performance

Fire protectionPlasterboard is designated a 'material of limited

combustibility' within the Building Regulations 1991. 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: 1970.

Fire resistanceThe 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 insulationThe Rw 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 controlWhere 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 propertiesIsowool 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/m2K. The use of 140mm studs with the same

thickness of Isowool 1005 can provide a U value down to

0.27W/m2K.

8

Roof designs


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 oneof timber studs at 600mm side of timber studs at of timber studs at 600mm side of existing plasterboardcentres. 600mm centres with one layer centres. partition using 50 x 50mm

fixed to Gyproc Resilient Bars timber battens at 400mmto one side plus 25mm centres with 50mm IsowoolIsowool 1200 in the cavity. 1200 between Gyproc

Resilient Bar fixed horizontallyand two layers of board.

...............................................................................................................................................................................Detail Board type Board Nominal Approx. Fire Laboratory sound insulation Performance

thickness partition weight resistance 100 — 3150Hz substantiationthickness No insulation 25mm report

Isowool 1200 ømm mm kg/m2 hours Rw dB Rw dB

...............................................................................................................................................................................

1 Multi–Board 6 87 15 ½ 34 – G106001

1 Wallboard 12.5 100 19 ½ 35 36 A026001 / 005

1 Duraline 12.5 100 28 ½ 36 – Q026021

1 Wallboard 15 105 23 ½ 37 40 A026002 / 006

2 SoundBloc 12.5 116 24 ½ 37 41 A046013 / 021

1 SoundBloc 12.5 100 23 ½ 38 40 A026011 / 016

2 Wallboard 12.5 116 20 ½ – 42 A046009 / 017

1 SoundBloc 15 105 27 ½ 40 43 A026014 / 017. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1 Fireline 15 130 30 1 ¶ 38 – A026023

3 Wallboard 12.5 125 36 1 38 42 A026003 / 007

3 SoundBloc 12.5 125 44 1 44 46 A026015 / 018

4 SoundBloc 15 196 48 1 – 52 § A05402. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3 Fireline 15 160 54 2 ¶ 41 – A026025...............................................................................................................................................................................Notes to Table 2The fire resistance and sound insulation performances are for partitions and walls incorporating tapered edge boards with all joints taped andfilled according to British Gypsum’s recommendations. The quoted performances are achieved only if British Gypsum components are usedthroughout, and the Company's fixing recommendations are strictly observed. Any variations in the specifications should be checked withBritish 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 1200.ø An equivalent sound insulation improvement can be achieved using 60mm Isowool 1000.

9

1 2 3 4


1 2 3 4

Table 3 Timber stud separating and compartment walls with Gyproc linings

Separating / compartment walls Compartment walls100% load ratio

Two separate timber frames Two separate timber frames Two layers of board each side Two layers of board each sidespaced 50mm apart, consisting consisting of 89 x 38mm timber of 75 x 38mm timber studs at of 75 x 38mm timber studs atof 89 x 38mm timber studs at studs at 600mm centres with 600mm centres with Gyproc 600mm centres with Gyproc600mm centres with mid–height mid–height noggings. Two layers Resilient Bars fixed horizontally Resilient Bars fixed horizontallynoggings. 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 thebetween the studs on one side. on one side. the cavity. cavity.

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 100 — 3150Hz substantiationthickness report

mm mm kg/m2 hours Rw dB...............................................................................................................................................................................

5 Duraline 12.5 225 (min) 30 1 38 Q026024

5 Wallboard 25 (2 x 12.5) 250 (min) 40 1 38 A046025

3 SoundBloc 25 (2 x 12.5) 141 46 1 56 A046005

4 SoundBloc 25 (2 x 12.5) 157 47 1 59 A046006

2 SoundBloc 30 (2 x 15) 263 (min) 55 1 61 A036002 ¶

1 Wallboard / Plank 12.5 + 19 263 (min) 54 1 63 A046022 ¶

1 SoundBloc / Plank 12.5 + 19 263 (min) 58 1 64 A036001 ¶. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3 SoundBloc 30 (2 x 15) 151 54 1½ 58 A046007

3 SoundBloc / Plank 12.5 + 19 154 57 1½ 58 A046023

4 SoundBloc 30 (2 x 15) 167 55 1½ 60 A046008

4 SoundBloc / Plank 12.5 + 19 170 58 1½ 60 A046024...............................................................................................................................................................................Notes to Table 3The fire resistance and sound insulation performances are for walls incorporating tapered edge boards with all joints taped and filled accordingto British Gypsum’s recommendations. The quoted performances are achieved only if British Gypsum components are used throughout, and theCompany'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 thesurrounding structure. The combination of ceiling and truss cladding is essential to meet the acoustic requirements of Building Regulations (seeconstruction 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 theEngland and Wales Building Regulations. Part B refers to fire resisting constructions as "Compartment" walls, and Part E to sound resistingconstructions as "Separating" walls. Please note, however, that not all walls designated as "Compartment" under Part B will be required toperform 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 0990 456123.

5

10


11

Table 4 Timber frame external walls

Cladding of 100mm aggregate block § with Cladding of 103mm facing brick ø Cladding ‡ comprising vertical tile hanging20mm render tied with stainless steel wall ties tied with stainless steel wall ties across on treated 25mm battens fixed throughacross a nominal 50mm clear cavity through a nominal 50mm clear cavity through breather membrane and sheathing boardbreather 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 substantiationhours ¶ W/m2K 100 — 3150Hz, Rw dB report

...............................................................................................................................................................................

1 One layer of 12.5mm Gyproc Wallboard Duplex ½ 0.39 50 – 55 A066001

2 One layer of 12.5mm Gyproc Wallboard Duplex ½ 0.41 50 – 55 A066002

3 One layer of 12.5mm Gyproc Wallboard Duplex ½ 0.44 40 – 45 A066003. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1 Inner layer of 12.5mm Gyproc Wallboard and 1 0.38 50 – 55 A066007

outer layer of 12.5mm Gyproc Wallboard Duplex


outer layer of 12.5mm Gyproc Wallboard Duplex


outer layer of 12.5mm Gyproc Wallboard Duplex...............................................................................................................................................................................Notes to Table 4The fire resistances quoted are for loadbearing walls tested with fire exposure to the internal face. Performances are for walls incorporatingtapered edge boards with all joints taped and filled according to British Gypsum's recommendations. The quoted performances are achievedonly if British Gypsum components are used throughout, and the Company's fixing recommendations are strictly observed. Any variations inthe 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 producelower U values. Contact British Gypsum Technical Service Department on 0990 456123 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 to85% 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 ThermalConductivity ( l )value used of 0.12W/mK for timber is based on that applicable to the Spruce / Pine / Fir groups from N. America and Europeused 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 theplasterboard, fixed to the face of the timber frame.¶ The fire resistance performances quoted are independent of any contribution from the external construction.§ Conductivity ( λλλλλ ) of block taken as 0.51 W/mK (1400 kg/m3)ø Conductivity ( λλλλλ ) 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.

283mm 265mm

1 2 3

215mm


Table 5 Timber joist floors with Gyproc ceiling linings

...............................................................................................................................................................................Detail Board type Flooring Joist Joist Fire Estimated laboratory Performance

board centres width resistance sound insulation § substantiationtype (min.) 100 — 3150Hz report

Airborne Impactmm mm hours Rw dB Lnw dB

...............................................................................................................................................................................1 One layer of 12.5mm Gyproc Wallboard a ø 600 38 ½ (modified) ø 38 79 C016001

2 One layer of 12.5mm Gyproc Wallboard a 600 38 ½ (modified) ø 42 71 V106007. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1 One layer of 12.5mm Gyproc Wallboard c 450 ¶ 38 ½ 37 82 C014003

1 One layer of 15mm Gyproc Wallboard a 600 ¶ 38 ½ 38 79 C016005. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1 Two layers of 15mm Gyproc Wallboard c 600 ¶ 47 1 40 76 C016006

1 Inner layer of 12.5mm Gyproc Fireline a 600 38 1 40 76 C016008and outer layer of 15mm Gyproc Fireline

1 Two layers of 12.5mm Gyproc Fireline b 600 38 1 40 76 C016009

2 Inner layer of Gyproc Plank and a 600 38 1 45 69 V106008outer layer of 12.5mm Gyproc Wallboard

4 Inner layer of Gyproc Plank and a 600 38 1 50 68 C206003outer layer of 12.5mm Gyproc Wallboard

3 Inner layer of Gyproc Plank and a 600 38 1 52 66 C206004outer layer of 12.5mm Gyproc Wallboard

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 Two layers of 15mm Gyproc Fireline b 450 ¶ 47 1½ 40 78 C014011

...............................................................................................................................................................................Notes to Table 5The fire resistance and sound insulation performances are for ceilings incorporating tapered edge boards with all joints taped and filledaccording to British Gypsum's recommendations. The quoted performances are achieved only if British Gypsum components are usedthroughout, and the Company's fixing recommendations are strictly observed. Any variations in the specifications should be checked withBritish 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 ceilingboards 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/m3.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

1 2 3 4

Standard timber floorwith no insulation

Minimum 30mm Gyproc Alpha FloorScreed on 1000 gauge polythene sheet(taped at joints) laid on Expamet wire

reinforced mesh with Gyproc Edge Stripsto perimeter on any suitable floor deck.

Gyproc Gyplyner Ceilingframework to joists.

Gyproc Resilient Bars at450mm centres to underside

of joists.


13

Table 6 Compartment / separating floors

Platform floor. Platform floor. Gyproc Gyplyner Gyproc SI Floor with Gyproc Plank100mm 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 onSIF Channels. 100mm Isowool 1000 in cavity. platform floor. 1000 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 anysuitable 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 100 — 3150Hz substantiationtype (min.) Airborne Impact report

mm mm hours Rw dB Lnw dB...............................................................................................................................................................................

6 One layer of 15mm Gyproc Fireline ‡ a 600 47 1 60 56 V106005

3 Two layers of 12.5mm Gyproc SoundBloc b 450 44 1 61 56 C204006

1 Gyproc Plank with outer layer of c 600 44 1 62 56 C016038 §12.5mm Gyproc SoundBloc

3 One layer of Gyproc Plank and b 450 44 1 63 55 C204001 §one layer of 12.5mm Gyproc SoundBloc

4 One layer of Gyproc Plank and b 450 44 1 63 55 C154008one layer of 12.5mm Gyproc SoundBloc

2 Two layers of 12.5mm Gyproc SoundBloc c 600 44 1 66 50 C106011

5 Two layers of 15mm Gyproc SoundBloc c 600 47 1 66 ø 48 C106050. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3 Two layers of 15mm Gyproc Fireline b 450 44 1½ 60 57 C204002...............................................................................................................................................................................Notes to Table 6The fire resistance and sound insulation performances are for ceilings incorporating tapered edge boards with all joints taped and filledaccording 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 ceilingboards 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 theEngland and Wales Building Regulations. Part B refers to fire resisting constructions as "Compartment" walls, and Part E to sound resistingconstruction as "Separating" walls. Please note, however, that not all walls designated as "Compartment" under Part B will be required toperform 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 ofGyproc Plank laid on 25mm Isowool 6405 (64kg/m3) 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 acoustictesting and fire resistance assessment. Before specifying this construction, advice should be sought from a suitably qualified timber or structuralengineer 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/m2. The 30N/mm2 grade of Gyproc Alpha Floor Screed has a flexuralstrength of at least 6N/mm2.

1 2 3

4 5 6


14

1 2 3

Table 8 Cavity barriers

Detail Construction Fire resistance PerformanceIntegrity : Insulation substantiation

minutes report...............................................................................................................................................................................

10mm Glasroc Multi–Board fixed to one side of a timber stud framework 30 15 G110002or trusses at maximum 600mm centres using Gyproc Nails or Screwsat 230mm centres. Fire–stopping to the perimeter as necessary.

As above but with 12.5mm Gyproc Fireline 30 15 E106002

Isowool Sleeved Cavity Fire Barrier sealing the cavity between the outer brick wall 30 30 ¶ E106004

and the internal timber frame leaf.

...............................................................................................................................................................................Notes to Table 8The fire resistances are for barriers with all joints taped and filled according to British Gypsum's recommendations. The quoted performancesare achieved only if British Gypsum components are used throughout, and the Company's fixing recommendations are strictly observed. Anyvariations 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 minutesinsulation.

Table 7 Ceilings below roof spaces

Timber joists or bottom chord of trusses with suitable timber noggings between joists to Gyproc Gyplyner or MF Suspendedsupport 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 substantiationmm mm mm hours report

...............................................................................................................................................................................1 One layer 12.5mm Glasroc Multi–Board 600 38 Isowool 1000 150 ½ G106041

2 Two layers 12.5mm Gyproc Wallboard 600 50 Isowool 1000 150 ½ C106049

1 One layer 12.5mm Gyproc Fireline 600 38 Isowool 1000 150 ½ C106047

4 Two layers 12.5mm Gyproc Wallboard 600 35 Isowool 1000 150 ½ C106045. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2 Two layers 10mm Glasroc Multi–Board 600 35 Isowool 1000 150 1 G106042

3 Two layers 12.5mm Gyproc Fireline 600 38 Rock mineral 150 1 C106048wool (24kg/m3)

4 Two layers 12.5mm Gyproc Fireline 600 35 Rock mineral 30 1 C106046wool (45kg/m3)

...............................................................................................................................................................................Notes to Table 7The fire resistance performances are for imperforate ceilings incorporating tapered edge boards with all joints taped and filled according toBritish Gypsum's recommendations. The quoted performances are achieved only if British Gypsum components are used throughout, and theCompany'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 oftimber supports where the ceiling boards butt in order to maintain an adequate bearing surface (refer to Board fixing on site, Fig 1).

4


15

Specification clauses

For details of Specification Clauses contact British GypsumTechnical Service Department on 0990 456123.

Design

When designing timber frame buildings, the designer shouldtake account of relevant British Standards, Documents, andassociated literature. General guidance can be obtained bycontacting the Timber and Brick Information Council on01923 778136. For further guidance on British Gypsumproducts and systems, refer to The White Book, or contactBritish Gypsum Technical Service Department on 0990 456123.

General considerationsEnsure that fixing recommendations are followed for the

specific board to be installed – refer to current BritishGypsum literature.

Consider using Gyproc Drywall Screws to eliminate the riskof nail popping.

Consider using Gyproc Duplex grade board where there is aneed for vapour control.

Site conditions must be suitable for the installation ofplasterboard, e.g. building sealed against the elements, wettrades finished (floor screeds etc.).

Timber must be aligned and levelled, and should satisfy therequirements of BS 5268: Part 2: 1991.

When textured coatings are specified the manufacturer'srecommendations must be followed.

Ensure that the floor construction is suitable to support anyimposed loads, such as the inclusion of thermal insulation inthe cavity.

If ceiling heating is specified for use with plasterboard, themanufacturer's recommendations must be followed.

Ensure that cavity barriers are installed where required inorder to satisfy national Building Regulations, particularly inperimeter walls in roof spaces and at roof / separating walljunctions.

Racking resistancePlasterboard products contribute to the racking resistance oftimber frames in accordance with BS 5268: Section 6.1: 1988

Strength and robustnessThe dimensions and assembly of timber supports should besufficient to allow positive fixing of boards without bounceor undue deflection because of nailing, screwing, or otherapplied force. When the above fixing conditions cannot bemet, a timber batten should be securely fixed to the side ofthe timber support to increase the bearing surface.

Where boards are fixed at maximum centres in adverseconditions, the standard of lining can be affected. Adverseconditions can generally be described as conditions wherehigh humidity occurs, principally in the cold, damp autumn /winter period. They also refer to buildings under constructionduring this period where both the structure and wet

applications such as plastering and screeding are subject toslow drying conditions.

In small flat–roof areas, where a polythene vapour controllayer is included in the ceiling construction, condensation canform on the polythene surface. This can result in plasterboardbecoming unduly damp, and affecting the standard ofacceptability of the lining, and any applied plaster ortextured coating.

Sound insulationIn designing for sound insulation it is important to set targetswhich are correct in terms of the uses of spaces separated by

partitions and walls. The table below can be used for guidance.

Table 9 Degree of acoustic privacy

Rw Speech level.....................................................................................

25 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 penetrationsSuitable detailing will be required at service penetrations ifspecified levels of fire resistance and sound insulation are tobe achieved. Refer to construction details F and M, whichhave been shown by tests to maintain integrity.

Room in a roofWhere Gyproc plasterboard is used to line a room in a rooffor the purposes of fire resistance, a surface sloping morethan 70º from vertical is treated as a ceiling, and less than 70ºfrom vertical as a wall lining.

Timber noggingsPerimeter support, using either min. 38 x 38mm timbernoggings or plasterboard clips, may be required betweenceiling joists to support board edges. The provision ofnoggings depends on the thickness of boards used, and thespacing of timber joists. Timber noggings / clips should alwaysbe provided at the room perimeter with the exception thatthey are not required when using 15mm Gyproc Wallboard.

Nail poppingLoosening of nails in timber can occur through timbershrinkage, or as a result of fixing boards to misaligned ortwisted framing. To reduce the risk, boards should be fixedtight to framing members. Where the risk of nail popping isunacceptable, consideration should be given to fixing usingGyproc Drywall Screws. For further advice contact BritishGypsum Technical Service department on 0990 456123.

•

•

•

•

•

•

•

•

•


16

Partition junctionsWhere 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).

ServicesElectrical 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 7671. Cables located within

thermal insulation may need to be up–rated to counter the

effect of overheating (IEE Regulations refer).

FixturesThe 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 systemsstorage heating the fixing to be made back to theunits; structure using a proprietarycentral heating fixing. The cavity may need to beboilers. blocked.

.....................................................................................Medium to Wall cupboards; Mushroom plugs, proprietaryheavyweight 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 proprietaryfixings are given in the British Gypsum White Book, or TechnicalInformation leaflet – 'Fixtures to plasterboard', and in the Timber andBrick Information Council publications 'Living in a Timber and BrickHome', and the Timber and Brick Homes Handbook.

Ceramic tilingCeramic tiles up to 12.5mm thick with a maximum weight of

32kg/m2 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.

FinishingPlasterboards (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.


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

Key Drawings - Flats / Commercial buildings

Cross section

Longitudinalsection

Plan

Cross sectionLongitudinalsection


18

Construction – individual details

A C

B D


19


E F

G H



20

J L

K M



21

N Q

P R



22

S U

T V



23

W Y

X Z


List of details by reference letter

Detail Reference Title

A Typical Eaves detail

B External wall/ground floor

C Non loadbearing partition/upper floor ceiling

D Non loadbearing partition/ground floor

E External wall to verge

F Compartment (Separating) wall to underside of tiled roof

G External wall/timber joist floor

H Compartment (Separating) wall junction with timber joist floor. (Small electrical outlet box detail

also shown)

J External wall/Compartment (Separating) floor with typical window head

K External wall with typical window cill

L Compartment (Separating) floor junction with Compartment (Separating) wall

M Compartment (Separating) wall with larger electrical outlet box

N Non-loadbearing partition on Compartment (Separating) floor

P Compartment (Separating) floor junction with loadbearing partition under

Q Compartment (Separating) floor with loadbearing partition under and non loadbearing partition over

R Compartment (Separating) floor junction with loadbearing partition top and bottom

S Non loadbearing partition on timber joist floor

T Loadbearing partition/ground floor

U Loadbearing or non-loadbearing partition under timber joist floor

V Compartment (Separating) wall/ground floor

W Compartment (Separating) wall junction with internal partition on plan

X External wall with internal partition junction and typical door jamb on plan

Y Compartment (Separating) wall junction with external wall showing typical window jamb on plan

Z 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


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/m3 (Isowool

Timber Frame Batts - 1005).

12. 25mm glass wool 60 - 100 kg/m3 (Isowool Sound

Deadening Floor Slabs 25mm thick - 6405).

13. 100mm mineral wool minimum 10kg/m3 (Isowool

General Purpose Roll - 1000).

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.

Annotation notes to Construction details

22. 40m 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 floorwhen panels are supported construction

on ground floor joistsor 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......................................................................................................

26. 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


26

Board fixing on site

The following gives an appreciation of installation

procedures. For full fixing details contact British Gypsum

Technical Service Department on 0990 456123.

Timber frame external wallsFactory–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 wallsTimber 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.

Timber joist ceilings and compartment floorsRun 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.

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).

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.

ServicesElectrical 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 centreswith noggings without noggings

mm mm mm.....................................................................................

9.5 450 400

12.5 600 450

15 — 600

19 — 750.....................................................................................¶ Noggings are recommended for Fireline board and Duplex gradeboards, regardless of joist spacing, to ensure that fire and/or vapourcontrol integrity is maintained. When fixing Gyproc Lath orBaseboard, noggings are not required in the field of the boards.

35mm 25mm

Fig 1 Fixing boards to trussed rafters


27

6mmmin

Boards should be lightly butted with a max. separation of 3mm.Where a cut edge occurs dimension A is 13mm min; where a boundedge occurs dimension A is 10mm min.

A

Fig 2 Fixing tolerances

Nail / screw–fixingTable 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 fixthickness to fix plasterboard for plasterboard for direct

direct decoration decoration or plasteringto timber

mm mm mm.....................................................................................

9.5 32 30

12.5 36 40

15 36 40

19 42 50

12.5 over 12.5 50 50

15 over 15 60 65

12.5 over 19 60 65

15 over 19 60 65.....................................................................................Note:Nail fixing to timber supports.Drive the nails into the timber straight – not skewed and not closerthan 6mm from the timber edge (see Fig 2). If the timber support hasinsufficient bearing surface, fix a further timber support to it, or, inthe case of joists and trusses, consider using suitablecounter–battens. Drive the nails firmly home without fracturing thepaper surface, but leaving a shallow depression to facilitate spotting.

5.65m high structural elements

Built-up elements


28

Prefabrication

Structural elements

Typical Dormer windowInternal structure


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 :

British Gypsum Limited

Technical Service Department

East Leake

Loughborough

Leics.

LE12 6JT

Tel : 0990 456123

Fax : 0990 456356

For technical information and guidance on structural

elements, construction details, cladding options, and the

Timber and Brick Q–mark, contact :

The Timber and Brick Information Council

Gable House

40 High Street

Rickmansworth

Herts.

WD3 1ES

Tel : 01923 778136

Fax : 01923 720724

email [email protected]

29

Written enquiries Technical service Price £15..................................................................................................................................................................................

Written enquiries should be British Gypsum technical staff are available for discussion and toaddressed to:- render technical advice when the Company's products are being

specified or used. These services are available nationallyBritish Gypsum Limited through the numbers listed below.Technical Service Dept.East Leake Telephone 0990 456123LoughboroughLeicestershire LE12 6JT Fax 0990 456356 © British Gypsum March 1998 TFC–V1..................................................................................................................................................................................

Q.5978

A BPB group company

British Gypsum..................................................................................................................................................................................

UK market leader in gypsum plaster and plasterboardsystems, British Gypsum markets its products under theGyproc, Glasroc, Carlite, Thistle and Isowool brand names.Isowool is a registered trade name of British Gypsum–Isover Ltd.

British Gypsum operates quality assurance procedures toBS EN ISO 9002 and maintains the quality and leading edgeperformance of its products and systems through anextensive and on-going programme of research,development and testing, supported by in-house fire,acoustic and system test facilities which are unique amongstbuilding product manufacturers and match the best availableanywhere in the UK.

British Gypsum quality does not stop at the productsthemselves. CAD and technical support for specifiers;comprehensive on-site support and off-site training throughthree dedicated product training centres at East Leake nearNottingham, Kirkby Thore in Cumbria, and Erith in Kent, andex-stock or next day availability through more than 4000builder's merchants nationwide are just a part of a customersupport package that has, for many years, set British Gypsumapart in the market place.

British Gypsum further benefits from being a member ofEurope's leading gypsum company, BPB plc, which hasinterests in a wide range of associated building products andprovides an extensive pool of knowledge and experience tothe benefit of all its member companies.