Posi-Joist

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Open Web Joists
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Open Web Joists

• Product Overview

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What is an Open Web Joist?

• In Essence they are Warren Girders
• Manufactured from
• TR26 Grade Truss Timber
• Steel Webs

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Common Questions

• What depths do they come in?

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Depths
With 47mm timber on flat, there are 6 sizes of
web / joist
Strut Size Overall Depth Gap Depth
PS8 202mm 108mm
PS9N 225mm 131mm
PS10N 254mm 160mm
PS12 302mm 208mm
PS14N 373mm 279mm
PS16N 421mm 327mm
However
There are also a number of factors to consider
here, like span, centres, flange width and
loading conditions.
Beams may also be on edge
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Common Questions

• What depths do they come in?
• How are they made?

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Strut Runner

• Joists can also be made on a normal truss press
  but there may be problems restraining the top
  edge of the timber using standard truss clamps

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Common Questions

• What depths do they come in?
• How are they made?
• What width flanges to they have?

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Flange Widths

• 47mm on edge
• 72mm - 147mm on flat
• Maximum 4ply on edge
• Maximum 2 ply on flat (Up to 294mm)

On a standard run of joists you ideally want the
flange width to be 72mm or 97mm on flat.
Maximum recommended chords on edge are 97mm
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Common Questions

• What depths do they come in?
• How are they made?
• What width flanges to they have?
• How do they compare in price to solid timber and
  I-Joists?

However
Singly, they may be a little more expensive.
and fit quicker
Span further
They Give better access for services
RESULT
The overall job is cheaper
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Benefits of Open Web Joist

• Access for services

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Access for Services
Note soil pipe next to the bearing
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Access for Services
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Benefits of Open Web Joist

• Access for services
• Larger spans than cut timber I-Joist

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I-Joist Span Tables

• 241 deep, Series 550 Joist _at_ Rating 45 Spans 4.3m

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Open Web Joist Spans

• 254 deep PS10N Spans 5.14m Thats 0.84m more

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Open Web Joist Spans

• Based on 400mm centres and standard loads

72mm 97mm 122mm 147mm
PS 8 4880 5210 5480 5695
PS 9N 5100 5430 5685 5900
PS 10N 5520 5880 6160 6400
PS 12 6330 6760 7120 7410
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Benefits of Open Web Joist

• Access for services
• Larger spans than cut timber I-Joist
• Inherently stable faster assembly, minimal
  bracing

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I-Joist Bracing Requirements
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Open Web Joist Bracing Requirements
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Benefits of Open Web Joist

• Access for services
• Larger spans than cut timber I-Joist
• Inherently stable faster assembly, minimal
  bracing
• Light weight

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Benefits of Open Web Joist

• Access for services
• Larger spans than cut timber I-Joist
• Inherently stable faster assembly, minimal
  bracing
• Light weight
• Rigid design easier manual handling than
  I-Joist

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Benefits of Open Web Joist

• Access for services
• Larger spans than cut timber I-Joist
• Inherently stable faster assembly, minimal
  bracing
• Light weight
• Rigid design easier manual handling than
  I-Joist
• Squeak free cross grain shrinkage is minimal

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Benefits of Open Web Joist

• Access for services
• Larger spans than cut timber I-Joist
• Inherently stable faster assembly, minimal
  bracing
• Light weight
• Rigid design easier manual handling than
  I-Joist
• Squeak free cross grain shrinkage is minimal
• Versatility

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Open Web Joist Versatility
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Open Web Joist Versatility
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Trend towards Multi-Storey Dwellings
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Open Web Joist Growth Since 1997