Timber Specification Guidelines

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Timber Specification Guidelines
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Timber in building

• Timber is a major building and preferable ESD
  material.
• It is renewable, drawn from trees whose growth
  and harvest is managed by forestry.
• Sustainable forest management is necessary for
  building a sustainable society.

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Timbers resource takes time to grow

• Trees take at least 25-40 years to grow into a
  size usable for timber.
• Todays designers live with forest management
  decisions made prior to 1960.
• Actions taken now will only have full effect
  after 2040.

Forest mosaic reserve areas between plantations
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Timbers changing properties

• Moves to sustainable forest management are
  changing the character of available timber
• Plantation pine is largely restricted to
  structural uses, due to its softness and knots
• Mature native forest hardwood logs are large and
  slowly grown but, with increasing conservation
  reserves, their supply is limited
• Regrowth native forest hardwood logs are cut
  earlier and are making up more of the supply
  while
• Plantation hardwood is still more quickly grown
  and cut. Its qualities as solid wood product are
  still to be established.

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Changes in timber supply

• Due to these changes, the character and
  availability of timber is changing, including
• The availability of sizes
• Density hardness
• Strength durability
• Colour grain and
• Feature.

Drying hardwood
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Design implications of this change

• New aesthetic options
• A broader range of assembled sections
• Different detailing and
• There is a need to use material that underpins
  sustainable expansion of forests.

High feature flooring
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A practitioners question

• What is the best source (native forest or
  plantation) and species of timber to use in
  applications?

Native regrowth forest
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Specification guide

• Use timber when it is suitable for the project.
• Timber has lower embodied energy than most other
  material.
• It is usually locally produced in regional area.
• This generates employment and diverse economic
  activity, a vital part of ESD

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Specification guide

• Ideally, use certified local timber or recycled
  timber if available and fit for purpose.
• If this is not available use local timber before
  imports.
• The processes for local timber production can be
  verified.
• Recycled timber, by definition, has limited
  supply.

Regrowth forest
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Specification guide

• Accept non-traditional species.
• Minor species harvested need to be used fully.
• Plantation species are selected for speed of
  growth, not for current market preference.

Minor species veneer
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Specification guide

• Understand the supply and characteristics of
  local species.
• Some species are not available in quantities
  large enough for national markets but can service
  local projects.
• They should have economic uses.

Rare Huon pine in furniture
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Specification guide

• Be aware that strength and stiffness
  relationships will change.
• Faster grown plantation hardwoods and softwoods
  are not going to be as strong as slower grown
  plantation or native forest material.

Hardwood and LVL framing
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Specification guide

• Do not specify large sawn sizes if assembled
  sections are available.
• Smaller logs cannot produce the same large sawn
  sections as older, larger logs.

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Specification guide

• Do not specify high appearance grades as a
  default. Use high feature material.
• High feature material from native forests should
  be used to its fullest potential.
• Plantation hardwoods may contain more high
  feature wood.

High feature veneer
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Specification guide

• Be careful with expectations of colour.
• In general, the colour of regrowth and plantation
  timber is lighter than mature wood and also less
  consistent.
• Be prepared to sort, and develop uses for new
  colour groups.

Silver wattle veneer
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Specification guide

• Select species for hard wearing applications
  carefully.
• In general, regrowth and plantation timber is
  softer than mature wood.

Theatre floor and seating
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Specification guide

• Detail timber in external applications well and
  finish carefully.
• Sustainability is not served by letting good
  timber rot because of bad detailing.

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Specification guide

• Use durable species externally or treat
  selectively.
• The most durable timber comes from mature
  material.
• Treatment increases the range of uses.

High durability posts and screens
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