Timber joist Timber joists ceilings and separating ... 6.5 - Timber joist.pdf · Timber joists...

306

Tim

ber

jois

ts c

eil

ing

s an

d s

ep

ara

tin

g /

co

mp

art

men

t fl

oo

rs

6.5

Timber joist

Ceilings to timber joist floors are an established form of

ceiling construction, which is widely used in both new

housing and refurbishment. Separating / compartment

floors are often specified as fire and sound resisting floors

in residential units such as flats and apartments to meet the

requirements of national Building Regulations.

The ceilings comprise one or two layers of Gyproc

plasterboard screw-fixed or nailed to traditional timber joist

supports. Isover glass mineral wool insulation can be

included in the floor cavity to improve acoustic performance.

Timber joist ceiling linings are quick and easy to install, and

provide a lining which can be jointed to give a seamless

finish ready for direct decoration or a traditional gypsum

plaster finish.

● Traditional and established method

● Versatile

● Use of Gyproc Drywall Timber Screws

minimises fixing defects

● Gypframe RB1 Resilient Bar to provide

enhanced acoustic performance and

eliminate nail-popping

● Can achieve high performance levels

● Quick and easy to install

Key facts

Gyproc plasterboard - direct fix with Gyproc Drywall Timber Screw

Gypframe RB1 Resilient Bar - indirect fix

1

2

1

2

Sector Guide

Off

ices

Ret

ail

Edu

cati

on

Ind

ust

rial

Cu

sto

dia

l

Res

iden

tial

-H

ou

sin

g

Res

iden

tial

-

Hig

h R

ise

✔ ✔ ✔ ✔ ✔ ✔ ✔✔

Co

mm

erci

al

Spo

rt &

Lei

sure

Hea

lth

care

Au

dit

ori

a

Ente

rtai

nm

ent

Res

iden

tial

-A

par

tmen

ts

book 6_jan10a:c01 Introduction v3.qxd 15/04/2010 19:44 Page 306

307

T 00353 1 629 8400 F 00353 1 623 7054 E [email protected]

Tim

ber

jois

ts c

eil

ing

s an

d s

ep

ara

tin

g /

co

mp

art

men

t fl

oo

rs

6.5

Health and SafetySafety Data Sheets for all Gypsum Industries’ products areavailable to download from our website: www.gypsum.ie,or via the Technical Sales Department.

Gyproc board products

Gyproc WallBoard 1, 2

Thickness 12.5, 15mm

Width 900, 1200mm

Gyproc FireLine 1


Width 1200mm

Gyproc SoundBloc 1


Width 1200mm

Gyproc Plank

Thickness 19mm

Width 600mm

Gyproc 4x2’s

Thickness 9.5, 12.5mm

Width 600mm

Glasroc F MultiBoard

Thickness 6, 10, 12.5mm

Width 1200mm

Glasroc F FireCase

Thickness 15mm

Width 1200mm

1 Moisture resistant boards are specifed in intermittent wet useareas e.g. shower areas, bathrooms and kitchens.2 Also available in DUPLEX grades where vapour control is required.pour check is required.

Gypframe metal products

Gypframe RB1 Resilient Bar

Prime dimension 16mm

Fixing and finishing products

Gyproc Drywall Timber Screws or Glasroc

FireCase Screws

For a positive direct fix of boards to

timber joists.

Gyproc Drywall Screws

For fixing ceiling lining boards to Gypframe

SureFix Bars or Resilient Bars.

Gyproc Sealant

Sealing air paths for optimum sound

insulation.

Gyproc jointing materials

For seamless jointing.

Gyproc Skimcoat, Gyproc Carlite Finish or

Gyproc Board Finish

To provide a plaster skim finish.

Isover Acoustic Roll

For enhanced acoustic performance.

Isover Modular Roll

For providing acoustic / thermal insulation.

Isover Sound Deadening Floor Slab

Stone mineral wool

For providing enhanced fire performance in

some applications.

COMPONENTS


308

www.gyproc.ieTi

mb

er

jois

ts c

eil

ing

s an

d s

ep

ara

tin

g /

co

mp

art

men

t fl

oo

rs

6.5

Direct fix plasterboard ceilingBoards are fixed to ceilings, prior to lining walls and

partitions, with the long edges at right angles to the joists.

Cut-ends are located over a joist or timber nogging

support. Timber noggings (where required) are fitted

between joists at room perimeters to support board edges.

Noggings may also be required to support board edges in

the field of the boards. Boards are preferably fixed to

timber supports using Gyproc Drywall Timber Screws, to

minimise fixing defects.

Indirect fix to Gypframe RB1 Resilient BarsThe bars are fixed through the single fixing flange to the

underside of timber joists (at 90° to them) using Gyproc

Drywall Screws. The first and last rows of Gypframe RB1

Resilient Bars are located at all wall perimeters. Boards are

fixed to the underside of Gypframe Resilient Bars with long

board edges at right angles to the bars. When fixing

boards, care must be taken to ensure that the plasterboard

fixing screws do not make contact with the joists.

INSTALLATION

For full installation details, refer to the Installation Guide at www.gypsum.ie

Direct fix plasterboard ceilingBoards are fixed to ceilings, prior to lining walls and

partitions, with the long edges at right angles to the joists.

Cut-ends are located over a joist or timber nogging

support. Timber noggings (where required) are fitted

between joists at room perimeters to support board edges.

Noggings may also be required to support board edges in

the field of the boards. Boards are preferably fixed to

timber supports using Gyproc Drywall Timber Screws, to

minimise fixing defects.

Indirect fix to Gypframe RB1 Resilient BarsThe bars are fixed through the single fixing flange to the

underside of timber joists (at 90° to them) using Gyproc

Drywall Screws. The first and last rows of Gypframe RB1

Resilient Bars are located at all wall perimeters. Boards are

fixed to the underside of Gypframe Resilient Bars with long

board edges at right angles to the bars. When fixing

boards, care must be taken to ensure that the plasterboard

fixing screws do not make contact with the joists.

book 6_jan10a:c01 Introduction v3.qxd 15/04/2010 19:45 08

309


PERFORMANCE

Please refer to section Introduction - for general considerations.6.1

Table 2 - Dimensions and performance1 - Gyproc plasterboard linings

1 32

Timber joists with suitable timber room perimeter noggings. Noggings also required to support

board edges, unless otherwise stated.

Gypframe RB1 ResilientBars at 450mm centres to

underside of joists.100mm Isover Modular

Roll in the cavity.

Detail Board type Flooring Joist Joist Fire Estimated laboratory Performanceboard centres width resistance6 sound insulation3 substantiationtype2 (min.) 100 - 3150Hz report

Airborne Impactmm mm mins Rw dB Lnw dB

One layer of 12.5mm Gyproc WallBoard d 450 38 305 36 81 C014003

One layer of 12.5mm Gyproc WallBoard a 600 38 30 (modified)4 38 79 C016001

One layer of 12.5mm Gyproc WallBoard d 600 38 30 38 79 C016002

One layer of 15mm Gyproc WallBoard c 600 38 305 40 - C106029

Two layers of 15mm Gyproc WallBoard d 600 47 60 40 76 C016006

Inner layer of 12.5mm Gyproc WallBoard c 600 38 60 40 76 C016008and an outer layer of 15mm Gyproc FireLine

Two layers of 12.5mm Gyproc FireLine d 600 38 60 40 76 C016009

Inner layer of Gyproc Plank and an outer b 600 50 60 40 75 C016007layer of 12.5mm Gyproc WallBoard

Inner layer of Gyproc Plank and an outer d 600 45 60 50 68 C206003layer of 12.5mm Gyproc WallBoard

Inner layer of Gyproc Plank and an outer d 600 45 60 54 67 C016030layer of 12.5mm Gyproc SoundBloc

Two layers of 15mm Gyproc FireLine d 450 47 90 40 78 C014011

1 The fire resistance and sound insulation performances are for ceilings incorporating tapered edge boards with all joints taped and filledaccording to Gypsum Industries’ recommendations. The quoted performances are achieved only if Gypsum Industries’ components areused throughout, and the Company’s fixing recommendations are strictly observed. Any variations in the specification should be checkedwith Gypsum Industries. Where boards are fixed direct to timber joists, screw-fixing is the preferred alternative to nail-fixing andminimises the risk of fixing defects occuring.2 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 18mm (finished) thickness.d Wood board t & g flooring, not less than 21mm (finished) thickness.

3 The acoustic ratings quoted above are based on 200mm deep joists and a walking surface of min. 9.6kg/m3.4 30 : 15 : 15. If the floor type d is used the fire resistance increases to a full 30 minutes.5 Noggings to support board edges not required.6 Board joints must be reinforced with Gyproc Paper Joint Tape for the quoted fire resistance periods to be achieved. Please refer tosection for full details.

1

1

1

1

2

2

2

2

2

3

3

Tim

ber

jois

ts c

eil

ing

s an

d s

ep

ara

tin

g /

co

mp

art

men

t fl

oo

rs

6.52.2


310

www.gyproc.ie

1 32

Table 3 - Dimensions and performance1 - non-combustible board linings

4 65

Detail Board type Flooring Joist Joist Insulation Fire Performanceboard centres width resistance5 substantiationtype2 (min.) report

mm mm mins

One layer of 6mm MultiBoard b 450 38 - 30 G104019

One layer of 12.5mm MultiBoard a 600 38 - 30 G106021

1 The fire resistance performances are for imperforate ceilings with all joints taped and filled in accordance with Gypsum Industries’recommendations. The quoted performances are achieved only if Gypsum Industries’ components are used throughout, and the Company’sfixing recommendations are strictly observed. Any variations in the specifications should be checked with Gypsum Industries. Where boardsare fixed direct to timber joists, screw-fixing is the preferred alternative to nail-fixing and minimising the risks of fixing defects occurring.2 Floor types: a 21mm plain edge wood board flooring.

b Wood board t & g flooring, not less than 18mm (finished) thickness.c Wood board t & g flooring, not less than 19mm (finished) thickness.d Wood board t & g flooring, not less than 20mm (finished) thickness, or 20mm plain edge boarding with 3mm

hardboard or plywood.3 Use 58mm FireCase Screws at 150mm centres. 38mm x 38mm timber noggings are also required between joists and at the perimeter tosupport board edges.4 Noggings to support board edges not required.5 Board joints must be reinforced with Gyproc Paper Joint Tape for the quoted fire resistance periods to be achieved. Please refer tosection for full details.

Two layers of 10mm MultiBoard a 600 47 - 60 G106022

Two layers of 10mm MultiBoard a 600 47 100mm Isover 60 G106023Modular Roll

80mm x 10mm MultiBoard strips b 4004 50 30mm stone mineral 60 G104024(screw-fixed), with one layer of 10mm wool (64kg/m3)Glasroc MultiBoard (screw-fixed)

80mm x 10mm MultiBoard strips c 600 50 60mm stone mineral 60 G106046(screw-fixed), with one layer of 10mm wool (23kg/m3)MultiBoard (screw-fixed)

One layer of 15mm FireCase S b 600 38 - 60 G106025(screw-fixed)3

100mm x 10mm MultiBoard strips d 6004 38 25mm stone mineral 60 G106026(screw-fixed), with one layer of 12.5mm wool (48kg/m3)MultiBoard (screw-fixed)

One layer of 12.5mm MultiBoard, d 6004 38 - 90 G106027100 x 10mm MultiBoard strips andan outer layer of 12.5mm MultiBoard

One layer of 12.5mm MultiBoard, d 6004 38 100mm Isover 90 G106028100 x 10mm MultiBoard strips and Modular Rollan outer layer of 12.5mm MultiBoard

Timber joists with suitable timber room perimeter noggings.Noggings also required to support board edges, unless stated otherwise.

1

1

1

2

3

4

4

4

5

6

Tim

ber

jois

ts c

eil

ing

s an

d s

ep

ara

tin

g /

co

mp

art

men

t fl

oo

rs

6.52.2


311


19mm Gyproc Bonding or with 2mm c 600 48 120 C016045Gyproc Skimcoat or Carlite Finish

Table 4 - Dimensions and performance1 - upgrading existing lath and plaster ceilings

1 32 4

Existing lath and plasterceiling supported bychicken wire securelynailed to the joists,

battened with 38mm x38mm timber (at 600mmcentres with noggings or450mm centres without

noggings).

Existing ceilingunderdrawn with

metal lath2 securelyfixed to the joists.

Existing lath and plasterceiling (up to 20mmthick) supported by

chicken wire securelynailed to the joists.

Existing ceilingremoved and metal

lath2 securely fixed tothe joists.

Detail Board type Flooring Joist Joist Fire Performanceboard centres width resistance7 substantiationtype3 (min.) report

mm mm mins

One layer of 12.5mm Gyproc WallBoard d 600 38 30 C016019

1 The fire resistance performances are for imperforate ceilings incorporating boards with all joints taped and filled according to GypsumIndustries’ recommendations. The quoted performances are achieved only if Gypsum Industries’ components are used throughout, and theCompany’s fixing recommendations are strictly observed. Any variations in the specifications should be checked with Gypsum Industries.Where boards are fixed direct to timber joists, screw-fixing is the preferred alternative to nail-fixing and minimises the risk of fixingdefects occurring.2 Where plaster is applied to ribbed metal lath, the plaster thickness is measured from the face of the lath, and the lath should be installedin accordance with the manufacturer’s recommendations. With 120 minutes fire resistance construction, the metal lath is independentlyfixed with wire supports from the joist sides.3 Floor types: a Wood board t & g flooring, not less than 20mm (finished) thickness, or 20mm plain edge boarding with 3mm

hardboard or plywood.b Wood board t & g flooring, not less than 21mm (finished) thickness, or 20mm plain edge boarding with 3mm

hardboard or plywood.c Wood board t & g flooring, not less than 22mm (finished) thickness, or 20mm plain edge boarding with 3mm

hardboard or plywood.d Any structurally suitable wood board flooring.

4 Assumes no contribution from the existing lath and plaster ceiling.5 Bridging comprises of a layer of 12.5mm Gyproc MultiBoard resting on 100mm x 12.5mm Gyproc MultiBoard strips which are screw-fixedto the sides of each joist flush with the bottom edge, strips fixed at 300mm centres, top and bottom.6 Fix MultiBoard strips at 300mm centres, top and bottom.7 Board joints must be reinforced with Gyproc Paper Joint Tape for the quoted fire resistance periods to be achieved. Please refer tosection for full details.

Two layers of 12.5mm Gyproc FireLine b 600 38 60 C016022

13mm Gyproc Bonding or with 2mm b 600 37 60 C016024Gyproc Skimcoat or Carlite Finish

Two layers of 10mm MultiBoard b 600 37 60 G106045

100mm x 10mm MultiBoard a 600 50 60 G106029with one layer of 12.5mm MultiBoard

1

1

1

2

3

4

Tim

ber

jois

ts c

eil

ing

s an

d s

ep

ara

tin

g /

co

mp

art

men

t fl

oo

rs

6.5

2.2


312

www.gyproc.ieTi

mb

er

jois

ts c

eil

ing

s an

d s

ep

ara

tin

g /

co

mp

art

men

t fl

oo

rs

6.5

Two layers of 15mm Gyproc FireLine b 450 45 90 60 57 C204002

4 5

Platform floor. 100mm Isover Modular

Roll between the joists. Floor type c3

Platform floor.

CasoLine MF4 hung underneath timber

joists to give a 277mm cavity, with

80mm Isover Modular Roll

between the joists. Floor type c3

GypFloor SILENT with Gyproc Plank

on Gypframe SIF Floor Channels.

100mm Isover Modular Roll in the

cavity. Gypframe RB1 Resilient bars

at 450mm centres.

Table 5 - Dimensions and performance1 - compartment / separating2 floors

1 32

Separating sub-joist floor

comprising of a platform floor.

100mm Isover Modular Roll in the cavity.

Floor type c3

GypFloor SILENT with Gyproc Plank on

Gypframe SIF Floor Channels.

100mm Isover Modular Roll in the

cavity. GypLyner framework to joists.

Detail Board type Flooring Joist Joist Fire Estimated laboratory Performanceboard centres width resistance5 sound insulation substantiationtype2 (min.) 100 - 3150Hz report

Airborne Impactmm mm mins Rw dB Lnw dB

One layer of Gyproc Plank with an outer c 600 44 60 62 56 C016038layer of 12.5mm Gyproc SoundBloc

Two layers of 15mm Gyproc SoundBloc c 600 44 60 66 50 C106011

Two layers of 15mm Gyproc SoundBloc b 450 45 60 61 56 C204006

One layer of Gyproc Plank and one layer b 450 45 60 63 55 C204001of 12.5mm Gyproc SoundBloc

One layer of Gyproc Plank and one layer b 450 45 60 63 55 C154008of 12.5mm Gyproc SoundBloc

Two layers of 15mm Gyproc SoundBloc c 600 47 60 664 48 C106050

1 The fire resistance and sound insulation performances are for ceilings incorporating tapered edge boards with all joints taped and filledaccording to Gypsum Industries’ recommendations. The quoted performances are achieved only if Gypsum Industries’ components areused throughout, and the Company’s fixing recommendations are strictly observed. Any variations in the specification should be checkedwith Gypsum Industries’. Where boards are fixed direct to timber joists, screw-fixing is the preferred alternative to nail-fixing andminimises the risk of fixing defects occuring.2 If in doubt as to whether a floor is to be a compartment or separating floor, or both, please refer to the relevant Technical Guidance Document.3 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 Isover Sound Deadening Floor Slabs (64kg/m3) laid on a minimumof 12mm wood based sheet sub-deck nailed to the joists.

4 Normal fixing centres for Gypframe MF5 Ceiling sections (450mm) and Gypframe MF7 Primary Support Channels (1200mm).5 Board joints must be reinforced with Gyproc Paper Joint Tape for the quoted fire resistance periods to be achieved. Please refer tosection for full details.

1

2

3

3

3

4

5

2.2


313


6.5

Two layers of 10mm Gyproc MultiBoard 600 354 150mm Isover 60 G106042Modular Roll

Two layers of 12.5mm Gyproc FireLine 600 38 150mm stone mineral 60 C106048Wool (24kg/m3)

Two layers of 15mm Gyproc FireLine 600 354 30mm stone mineral 60 C106051Wool (45kg/m3)

Table 6 - Dimensions and performance1 - upgrading sound insulation of a basic floor

1 32

195mm x 45mm timber joists at

600mm centres with 18mm t&g

wood chipboard flooring.

CasoLine MF hung underneath the basic

floor (ceiling removed) to give a

277mm cavity. 80mm Isover Modular

Roll in the cavity.

CasoLine MF hung from the basic floor

using Gypframe Acoustic Hangers to

give a 277mm cavity. 80mm

Isover Modular Roll in the cavity.

UpgradingExisting basic floor

Detail Board type Approximate Floor Laboratory sound insulation Performanceweight depth 100 - 3150Hz substantiation

Airborne Impact reportkg/m2 mm Rw dB Lnw dB

Existing layer of 12.5mm Gyproc plasterboard 10 226 38 79 C106028

Two layers of 12.5mm Gyproc SoundBloc 23 320 60 60 C106007

Two layers of 12.5mm Gyproc SoundBloc 23 320 63 54 C106013

1 The sound insulation performances are for imperforate ceilings with all joints taped and filled according to Gypsum Industries’recommendations. The quoted performances are achieved only if Gypsum Industries’ components are used throughout, and theCompany’s fixing recommendations are strictly observed. Any variations in the specifications should be checked with Gypsum Industries.

1

2

3

Table 7 - Dimensions and performance2 – ceilings below roof spaces

1 32 4

Detail Board type Max. joist/ Min. joist / Insulation Fire Performancetruss centres truss type resistance5 substantiation

width reportmm mm mins

One layer of 12.5mm MultiBoard 600 38 150mm Isover 30 G106041Modular Roll

Two layers of 12.5mm Gyproc WallBoard 600 38 150mm Isover 30 C106049Modular Roll

One layer of 12.5mm Gyproc FireLine 600 38 150mm Isover 30 C106047Modular Roll

Two layers of 12.5mm Gyproc WallBoard 600 354 100mm Isover 30 C106045Modular Roll

2 The fire resistance performances are for imperforate ceilings incorporating boards with all joints taped and filled according to BritishGypsum’s recommendations. The quoted performances are achieved only if Gypsum Industries components are used throughout, and theCompany’s fixing recommendations are strictly adhered to. Any variations in the specifications should be checked with British Gypsum. Whereboards are fixed direct to timber joists, screw-fixing is the preferred alternative to nail-fixing and minimises the risk of fixing defects occuring.3 For fire-rated ceilings below roof spaces, noggings are required regardless of joist spacings and plasterboard thickness.4 Nominal 50mm x 25mm timber battens should be fixed to the side of timber supports where the ceiling boards butt in order to maintain anadequate bearing surface.5 Board joints must be reinforced with Gyproc Paper Joint Tape for the quoted fire resistance periods to be achieved. Please refer tosection for full details.

1

1

2

2

3

4

4

Timber joists or bottom chord of trusses with timber noggings between joists to support board edges and at room perimeter.3

Insulation laid between joists.CasoLine MF hung from joists.

Insulation laid over ceiling grid.

Tim

ber

jois

ts c

eil

ing

s an

d s

ep

ara

tin

g /

co

mp

art

men

t fl

oo

rs

2.2


314

www.gyproc.ie

EnvironmentalGyproc plasterboard ceilings are unsuitable for use in areas

subject to continuously damp or humid conditions.

Plasterboards are not suitable for use in temperatures

above 49ºC but can be subjected to freezing conditions

without risk of damage.

Fire protection For reaction to fire classifications for Gyproc and Glasrocboards please refer to Section .

Fire resistanceThe fire resistances given in Tables 2, 3, 4, 5, 6 and 8 are for

imperforate ceilings tested to BS 476: Part 8: 1972 or

BS 476: Part 21: 1987, or BS 476: Part 22: 1987, or

assessments based on these tests.

Sound insulationThe airborne and impact sound ratings given in Tables

2, 6 and 7 are for imperforate ceilings and have been

tested in accordance with BS EN ISO 140-3: 1995 and

BS EN ISO 140-6: 1998, and rated in accordance with

BS EN ISO 717-1: 1997 and BS EN ISO 717-2: 1997.

Airtightness is essential for optimum sound insulation.

While most junctions will be sealed with standard jointing

materials, gaps at the perimeter of the floor and ceiling,

and other small airpaths, can be sealed using Gyproc

Sealant.

The sound insulation data quoted was measured in the

absence of flanking transmission. The performance of the

floor in practice 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 second layer in double layer linings). The

application of two coats of Gyproc Drywall Sealer to the

face lining will also provide a degree of vapour control.

Please refer also to Timber noggings overleaf.

Thermal propertiesIsover insulation is laid between the joists where required

to provide the specified standard of thermal insulation.

DESIGN

Please refer to section Introduction - for general

considerations.

Planning - key factorsTo minimise the risk of ceiling finish defects occurring,

seasoned timber with a moisture content not exceeding

that recommended in BS 5268: Part 2: 2002 should be used.

The contractor should ensure that timber supports are

accurately spaced, aligned, and levelled. Consideration

should be given to using Gyproc Drywall Timber Screws as

the preferred method of fixing.

Cavity barriersCavity barriers may be required to satisfy the requirements

of national Building Regulations. Please refer to section

- Cavity barriers.

Strength and robustnessTimber should be aligned and level, and should meet the

requirements of BS 5268: Part 2: 2002. The dimensions and

assembly of timber supports should be sufficient to allow

positive fixing of boards without bounce or undue

deflection due to nailing, screwing, or other applied force.

When the minimum joist width conditions cannot be met, a

timber batten should be securely fixed to the side of those

timber supports where ceiling boards butt in order to

increase the bearing surface. Please refer to Joist width

overleaf.

Where plasterboards 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.

Where a polyethylene vapour control layer is included in

the ceiling construction in conditions described previously,

condensation can form on the polyethylene 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.

6.1

6.7

2.1

Tim

ber

jois

ts c

eil

ing

s an

d s

ep

ara

tin

g /

co

mp

art

men

t fl

oo

rs

6.5


315


Imposed loadsThe designer should ensure that the floor construction is

suitable to support any imposed loads.

Timber noggingsSuitable timber noggings, normally 38mm x 38mm, may be

required between joists and at the room perimeter to

support board edges and board ends. The provision of

noggings depends on the thickness of boards used, and the

spacing of timber joists (please see Table 8). In addition, the

need for noggings is also dependent on any fire resistance

requirements, so Tables 2 and 7 must be referred to.

Timber noggings should always be provided at the room

perimeter except when using 15mm board or 19mm Gyproc

Plank in non-fire rated situations. When fixing DUPLEX grade

boards providing vapour control noggings are required

regardless of joist spacing or board thickness in order to

ensure that vapour control integrity is maintained.

In multi-layer plasterboard ceilings, the provision of

noggings relates to the outer layer board only, unless

otherwise stated.

Nail poppingLoosening of nails in timber can occur through timber

shrinkage (please see Fig 7), or as a result of fixing boards

to misaligned or twisted framing. To reduce the risks,

boards should be fixed tight to framing members.

To minimise any risk of fixing defects occurring use Gyproc

Drywall Timber Screws. If nails are the preferred fixing

method, the risk of subsequent fixing defects can occur.

Fixing to super-dried timber and engineered ‘I’ beamsIt has been established by test that Gyproc Drywall Timber

Screws are the best solution for fixing to standard softwood,

super-dried timber (approximately 12% moisture content).

If engineered I joists are to be used, please contact the joist

manufacturer for fire resistance and sound insulation claims

and for fixing recommendations.

ServicesElectrical and other small service runs can be routed within

the floor cavity. Services should be installed in accordance

with standards, guidelines and recommendations.

Fixtures / fittingsFixtures should be made into joists, or to supplementary

timber.

FinishingPlease refer to section - Finishing Coat Plasters,

section - Jointing, and section - Decorative

Effects.

EstimatingThe estimated construction time is 15 - 20m2 / hour (single

layer ceiling - boarding only) or 8 - 10m2 / hour (double

layer ceiling - boarding only) ready for finishing.

Table 8 - Provision of timber noggings*

Board Maximum joist centresthickness with noggings without noggingsmm mm mm

6 MultiBoard 450 400

9.5 & 10 450 400

12.5 600 450

15 & 19 600 600

*Tables 2 to 7 must also be referred to for fire resistant ceilings.

2.2

1.5

2.5

Joist widthWhere joist width is less than the minimum stated in Tables 2 - 7, the system may not meet its specifiedperformance.

If the minimum fixing tolerances cannot be met, 50mm x

25mm timber battens should be screw-fixed to the side of

the joists where ceiling boards abut in order to extend the

bearing surface.

Fixing to timber framesA technical information sheet is available to download

from our website: www.gypsum.ie

Tim

ber

jois

ts c

eil

ing

s an

d s

ep

ara

tin

g /

co

mp

art

men

t fl

oo

rs

6.5


316

www.gyproc.ie

CONSTRUCTION DETAILS

Fig 1 - Joists at 450mm centres using 12.5mm Gyproc WallBoard - board edge noggings not required unless stated in

performance tables*

900mm

1800mm 450mm

Fig 2 - Joists at 600mm centres using 12.5mm Gyproc WallBoard - board edge noggings required unless stated in

performance tables*

1200mm

2400mm 600mm

* Note: where Duplex grade boards are specified to provide vapour control, noggings are always required regardless of joist spacingand plasterboard thickness.

* Note: where Duplex grade boards are specified to provide vapour control, noggings are always required regardless of joist spacingand plasterboard thickness.

Room perimeter noggings required.

Room perimeter noggings required.

Tim

ber

jois

ts c

eil

ing

s an

d s

ep

ara

tin

g /

co

mp

art

men

t fl

oo

rs

6.5


317


Fig 3 - Joists at 600mm centres using 15mm Gyproc WallBoard - board edge noggings not required unless stated in the

performance tables. Room perimeter noggings not required in non-fire rated situations*.

2400mm 600mm

1200mm

Fig 4 - Twisting of standard soft wood timber joist on drying from 20% to 8% moisture content

* Note: where Duplex grade boards are specified to provide vapour control, noggings are required regardless of joist spacing andplasterboard thickness.

Tim

ber

jois

ts c

eil

ing

s an

d s

ep

ara

tin

g /

co

mp

art

men

t fl

oo

rs

6.5


318

www.gyproc.ie

Fig 5 - Fixing boards to trussed rafters

Fig 6 - Fixing tolerances1

35mm 25mm

6mmminimum

A

Table 9 - Fixing plasterboard to timber supports

Board Gyproc Drywall Timber Gyproc Nails to fixthickness Screws to fix board for plasterboard for direct

direct decoration or decoration orplastering plastering

mm mm mm

9.5 32 3012.5 38 4015 38 4019 41 5012.5 over 12.5 51 5012.5 over 19 60 6515 over 15 60 6515 over 19 60 65

1 Boards should be lightly butted with a maximum separation of3mm. Where a cut edge occurs, dimension ‘A’ is 13mm minimum,.Where a bound edge occurs, dimension ‘A’ would be 10mmminimum.

Tim

ber

jois

ts c

eil

ing

s an

d s

ep

ara

tin

g /

co

mp

art

men

t fl

oo

rs

6.5


319


Tim

ber

jois

ts c

eil

ing

s an

d s

ep

ara

tin

g /

co

mp

art

men

t fl

oo

rs

6.5


Timber joist Timber joists ceilings and separating ... 6.5 - Timber joist.pdf · Timber joists...

Documents

Transcript of Timber joist Timber joists ceilings and separating ... 6.5 - Timber joist.pdf · Timber joists...