Metal Web Floor System

Contents

2

Contents

Introduction and benefits 3

easi-joist® definitions 4

easi-joist webs 5 - 6

Mechanical services 7

Loading and design 8

Floor stiffness 9

Internal non-loadbearing wall 10 - 11

Typical support details 12 - 13

Two ply girder and trimmer details 14

Edge closer details for timber frame and Internal bearing 15

Strongback installation and horizontal restraint strap details 16

Typical timber frame compartment floor and party wall with service void detail 17

Layout, positioning and lifting 18

Flooring, fixing and fire resistance 19

In t roduct ion and Benef i ts

3

Introduction easi-joists are parallel chord trusses utilising stress graded timberchords “on Flat” or “on Edge”.

These chords are plated together with a precision engineered andmanufactured structural component called the metal web, thesewhen combined form the easi-joist®.

The easi-joist® combines the lightness of timber with the structuralqualities of the metal web, together these two components offer anopportunity for designing commercial, domestic and industrial floorapplications with spans equal to and exceeding traditional timberjoists and there equivalent timber alternative, but with betterdamping and stiffness qualities.

easi-joist® is a precision designed and manufactured floor system,that is designed to make floor joist manufacture faster, more costeffective and easier to install.

Benefits

• Open web designThis allows for easier morepractical installation of servicesincluding waste water pipes,electrical cabling, heating pipesand other services.

• Reduced site wastagePrecisely manufactured easi-joistsvirtually eliminate all site alterationsthis cuts out on waste andpilfering.

• Light weightThe combination of smaller timbersections with the light weight metalweb means that finished product islighter than timber and muchlighter than timber equivalents.

• Speed and ease of erectionAs the timber is generally used “onflat” the minimum 72mm widthallows for a speedy set out prior tolaying floor boards without theneed for temporary bracing.

• Top chord supportThe easi-joist® is not limited in it’ssupport capabilities options tosupport on the top chord areincluded.

• Long term stabilityThe reduced sections used in themanufacture of the easi-joist®

combined with the metal webmeans; that less loss of moistureand shrinkage is seen meaning aquieter and longer lasting floorsystem.

• Comparative with timberThe easi-joist® system can bemanufactured to the minimumdepth required in the standardcodes of practice.

• Improved sound andvibrationThe metal web floor system allowsfor the installation of a rigidStrongback that reduces vibrationand improves the overallperformance of the floor.

eas i- jo is t Def in i t ions

4

End bearing

Top chord

Metal Web

Strongback

Top chord splice

End columnBottom chord

Bottom chord splice

Intermediate support

Column

Column plate

eas i- jo is t Webs

5

600mm

199mm

195mm

35mm

125mm

35mm

600mm

199mm

230mm

35mm

160mm

35mm

600mm

199mm

280mm

35mm

210mm

35mm

758mm

247mm

393mm

35mm

323mm

35mm

101mm

101mm

101mm

105mm

MS200

MS250

MS300

MS400

36mm easi-joist

eas i- jo is t Webs

6

600mm

199mm

219mm

47mm

125mm

47mm

600mm

199mm

254mm

47mm

160mm

47mm

600mm

199mm

304mm

47mm

210mm

47mm

758mm

247mm

417mm

47mm

323mm

47mm

101mm

101mm

101mm

105mm

MS200

MS250

MS300

MS400

47mm easi-joist

Mechan ica l Serv ices

7

easi-joists are designed to allow foreasy accommodation of electrical,plumbing, waste water and otherservices required within the floor joistarea with no cutting or notchingrequired.

Clearance for rectangular services

MS 200 MS 250 MS 300 MS 400

H mm W mm W mm W mm W mm

50 300 300 330 500

100 100 200 250 410

150 50 70 170 330

200 N/A N/A 70 250

250 N/A N/A N/A 170

300 N/A N/A N/A 70

Clearance for services

MS 200 MS 250 MS 300 MS 400

A (mm) 125 160 210 323

D (mm) 100 150 200 280

The chords for easi-joist must NEVERbe cut, notched or drilled in any waywithout written approval by a WolfSystems Ltd Engineer. Similarly themetal webs must NEVER be drilled,bent or removed for any reason.

W

D

A

H

Load ing and Des ign

8

Dead loadsThe weight of partition walls, floorcover, ceilings, self weight of joist andpermanent services.

Live loads(Imposed loads)Everything not nailed down, loadsproduced by the use and occupancyof the of the floor, the load assumedto be produced by the intendedoccupancy or use including theweight of movable partitions,distributed, concentrated, impact and inertia loads, but excluding wind loads.

“It is essential that both distributedlive loads and point live loadrequirements be consideredindependently for various types offloor loadings in accordance with thespecific British Standard associatedwith floor loads – BS 6399: Part 1:1996 incorporating amendment 1(11/10/2002)”

The easi-joist Software program willallow the detailer/designer to specifythe live loads applicable to eachsection of floor joist as these mayalter according to the use of the floor.

Any unusual loads that may berequired for the floor system i.e. hoist loads, spa baths etc must bechecked and written confirmationreceived from Wolf Systems Ltdbefore proceeding.

Load warningeasi-joists are not designed tosupport loadbearing walls. Any andall roof and beam loads are to besupported by external walls only,Written confirmation from WolfSystems Ltd would be required inadvance should evidence of theabove load conditions be evident.

Further to this any additional loadsthat may be imposed duringconstruction e.g. temporary supportof building materials that are likely tohave higher loads than those thejoists have been designed for mustbe included in the design loads.

Permanent services

Partition wallFloor covering

Dead loads

Live loads

Unusual loads

Strongback posts can be inserted aftererecting joists should additionalStrongbacks be required

F loor St i f fness

9

Factors affecting floorstiffnessThe dynamic action of any flooringsystem whether timber, concrete orsteel is dependent on a number offactors such as the eventual floorplan, the applied loads and finally thelevel of expectation of the occupants.

Strongback is sized, located andfixed correctly to the easi-joists.

(Strongback grids are generallyprovided at the centre of each4000mm span)

Other factors that that assist in thedamping effect are internal walls, thisis because in larger open areas floorstend to have a more dynamic action.

Other contributors are floor andceiling covering and floor linings thatare correctly screwed to the joists toreduce additional dynamic actionpresent in the floor.

Factors affecting floordampingThere are certain components of thebuilding structure which act togetherand reduce vibration of the floor, thisis known as damping.

One of the major contributors of thedamping effect (which will essentiallyimprove the easi-joist floor) is theStrongback.

It is essential for both the structuralintegrity and performance of the easi-joist floor system that the

Strongback

Strongback grid designedto automatically position theStrongback correctly

In terna l Non- loadbear ing Wal ls

10

Correct installation ofinternal non-loadbearingwalls (parallel)There are two accepted methods forinternal non loadbearing walls thatrun parallel with the easi-joiststhemselves.

Walls that are parallel to the easi-joist must have noggins at600mm centres between joists tosupport internal wall.

Method 1

Method 2

47 x 97 noggins at 600mm c/c

In the case where fitted flooring will be used after the internal wall isconstructed an additional easi-joistwill required below this wall tosupport both the floor in addition to the wall.

Double easi-joist providedunder wall to support floormaterial

10mm gap required forexpansion and contraction offloor material

Internal non-loadbearing wall

Universal “Z” clip (or similar)

Wall panel screw nailed ontonoggins with a minimum of 2 x 3.35 dia. galvanised nails(length to suit)

In terna l Non- loadbear ing Wal ls

11

Correct installation ofinternal non-loadbearingwalls (perpendicular)Again there are 2 accepted methodswith internal non-loadbearing walls,placed perpendicular to the easi-joists these do not requireadditional support.

Internal non-loadbearing wall

easi-joist

Method 2: Fitted floorNo additional support required forfitted flooring with internal wallsperpendicular to the easi-joistshowever a 10mm expansion gap isrequired between the floor boardsand wall.

Internal non-loadbearing wall

10mm gap required

easi-joist

Method 1: Platform floor

Typ ica l Suppor t Deta i l s

12

Bottom chord bearingsTypical Support details for easi-joistsinclude and are mainly joists onmasonry hangers. The use of joisthangers reduces the likelihood ofheat loss into the cavity and thetransmission of sound through theseparating walls.

Joist to masonry hanger

Hanger depth must matchdepth of joist

Block work/brickwork

Stud wall

Flooring

Ceiling lining

Wall lining

Joist hangers must alwaysmatch the height of the joistbeing used, this ensuresadequate lateral restraint,failure to comply will meanstrapping each joist aftererection.

Joist /masonry hangerInternal

Joist to masonry hanger

Hanger depth must matchdepth of joist

Concrete

Joist /masonry hangerConcrete beam

Joist on timber frame

Typ ica l Suppor t Deta i l s

13

Top chord bearings

Extended top chord on wallplate

Flooring

Continuous top chord

Flooring

Ceiling

Joist on I beam, hidden supportHidden Top chord support allows forcontinuous ceiling material.

Joist on I beam

Extended top chord

Ceiling

Steel I beam

Joist on top chord

Two P ly G i rder and Tr immer Deta i l

14

Two ply angles as specified bydesigner

Extended hangers

Two ply angles as specified bydesigner

Two ply girder

Packing piece to maintainceiling line

Beam depth to suit, beam tobe slotted through both joists

Trimmer detail

Edge Closer Deta i l fo r T imber Frame and In terna l Bear ing

15

35mm edge closer prefabricated faced withplywood and including a20mm lap at the top

47 x 72 top chord restraintfixed to joists either betweenjoists or attached to bottomchord web posts

50mm

Head binder to joists

Edge closer detail for timber frame

Lateral restraint detail

Internal bearing

Strongback Insta l la t ionand Hor izonta l Rest ra in t St rap Deta i l s

Strongback sizes andinstallationStrongbacks are installed within theeasi-joist at right angles and theirpurpose is to dampen the vibrationsby increasing the stiffness of the

easi-joist Strongback size Alternate StrongbackNominal Size TR26 Grade Lower Grade

MS200 72 X 35 TR26 97 X 35 C16

MS250 97 X 35 TR26 122 X 35 C16

MS300 122 X 35 TR26 142 X 35 C16

MS400 147 X35 TR26 172 X 35 C16

600mm Timber splice nailed by minimum6 no nails either side

Splice joint

16

Splice positioning and nailingpositions

Fixing & splicingStrongbacks must be fixed to vertical webs in each easi-joist with 2 no 3.15 x 75mm Nails.

Strongbacks may be spliced whererequired by using a 600mm sectionequally over joint and nailed using 6 no 3.15 x 42mm nails on either side of the join.300mm

easi-joist floor system and reducingthe deflection by load sharing.

Proper installation of the Strongbackand flooring material will ultimatelydetermine how well your easi-joistflooring system will work.

97 x 35/47mm twice nailed to brace using3.15 x 75mm long galvanised nails

Strap fixed with minimum of four fixings of which at least one is to be over the third joist

Horizontal restraint strapHorizontal bracing straps are required to be fixed to loadbearingwalls perpendicular to easi-joists. This member must be continuousover a minimum of three easi-joists.

Typ ica l T imber Frame Compartment F loor

17

200mmapprox

Service void

easi-joist parallel to wall

easi-joist bearing on wall

Mineral wool cavity barrier

100m mineral wool insulationquilt 23 kg/m2

5mm (min) foamedpolyethylene resilient flanking strip

resilient layer

Installation ofinsulation

Layout , Pos i t ion ing & L i f t ing

18

easi-joists typically placed perpendicular to loadbearing walls. Care should be taken to ensure thatthe correct spacing between the easi-joists as designed and indicatedon the layout is maintained throughout.Never exceed design spacing.

The correct bearing should also bemaintained on every easi-joist asspecified.

Lifting easi-joists may be lifted in eithersingle units or packs but care shouldbe taken to eliminate twisting,buckling, bending and dropping ofthe Joists, Slings should always beattached to the Timber Chord wherea panel point occurs.

45

Correct

Wrong

19

F loor ing, F ix ing and F i re Res is tance

Flooring and fixing

ExplanationThere are many different types offloor decking available the mostcommonly used is pre-cut chipboardin standard sizes, thickness may varyfrom 18 to 22mm depending on thespacing of the easi-joist®.

Any special instructions as indicatedby the manufacturers should benoted.

Basic guidelinesChipboard utilised in domesticflooring should be as per BScurrently used for solid timberequivalents.

Tongue and grooved boards shouldbe laid with the long edges runningperpendicular to the joists with jointsbetween the short edges occurringon the centreline of the joist.

Square edged boards need to besupported continuously along alledges.

Joints along short edge boardsshould be staggered and the lengthof any board should generally not beless than 2 x joist centres.

It is essential for a silent floor thatboards are supported with 50mm of their edges at the perimeter of thefloor by either joist or perimeter noggin.

Fixings shall be of a minimum lengthequal to 2.5 x board thicknessnails/screws should be positioned8mm from board edge and 200mmc/c along all supports and edges.

Chipboard is similar to other productsin that it expands and contractswhen exposed to high humidity,therefore it is recommended that a 10-12mm expansion gap leftbetween the boards and the face ofthe brickwork. Further to this a 2mmgap is recommended betweenabutting boards.

Part E soundTests are currently underway toascertain the minimum requirement toensure that the requirements Part Eare met fully. Wolf Systems suggestthat the details that currently applyfor solid joists which we assume tobe "worst case scenario", should be utilised until such time as specificrobust details are approved andagreed by local authorities.

Fire resistanceAll floors manufactured utilisingelements of timber rely on a contribution from the ceiling foroverall fire resistance. Party floorsrequire a minimum of 2 No 12mmPlasterboard to maintain the standardfire regulations. Standard domesticflooring requires minimum of 1 No 12mm Plasterboard.

The requirements for fire resistance in domestic floors structures is 30 minutes and for party floors is 60 minutes.

Full scale fire testing will be initiatedto comply with European standardsfor the easi-joist®, however for thepurpose of this initial manual it isrecommended that you utilise a“Worst case scenario” Being a solidtimber joist and therefore strictadherence to BS 5268: Part 4, Section 2.1 is required.

Ceiling boards are to be positionedsuch as their long edges run perpendicular to the easi-joists. The boards are fixed to the undersideof the joist using 3.2mm x 42mm long approved fire resistant screwspositioned at 150mm centres.

Joints that do not occur at a joistshould be backed with a 75mm widestrip of plasterboard of the same typeand thickness as the ceiling boardscrew centres to be minimum 150mm centres.

All joints must be taped with anapproved fire resistant 50mm widefibre tape and filled with an approved filler.

No apertures or service penetrationsshould be present except where fittedwith an improved fire resistant fitting(lights etc) or an appropriate firesealing system.

Wolf Systems LimitedShilton Industrial Estate,Shilton, Coventry CV7 9QL

T 08707 33 99 33

F 08707 33 99 55

E easi-joist@wolfsystem.co.uk

web site www.wolfsystem.co.uk

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