Structural Timber

Structural timber used in Australia for building outdoor living structures such as pergolas, decks, verandahs, alfresco area typically come in several types of which we discuss below.

Treated Pine

For all the various types of treatment, please visit treated pine timber guide.

Treated pine is the most popular used timber due to the following reasons:

  • Reasonably cheap & cost effective.
  • Supplies are easily sourced no matter your location.
  • One of the lightest timbers available.
  • Easy to work with, especially for a DIY builder.
  • Lasts for decades if well maintained.

If you plan to stain treated pine:

  • Clear stain typically cannot be used due to the light-yellow colour of the timber (unless you like yellow timber).
  • Most treated pine comes with stamped text on the timber which will need to be sanded off (especially difficult if laser cut/rough header pine, ie small grooves in the timber).

Most treated pine is structurally graded at MGP10, F5 or F8. For further information on this visit timber ratings.

Cypress Pine

Cypress pine is typically used for decking stumps and posts for verandahs, pergola, carports, etc.

Cypress pine is:

  • Reasonably cheap & cost effective.
  • Lighter timber compared to KD hardwood.
  • Can be used in ground with treatment.
  • Easy to work with, especially for a DIY builder.
  • Lasts for decades if well maintained.
  • Comes in rough sawn or dressed.
  • Is termite resistant.

More information can be found at wood species, cypress pine  .

Kiln Dried Hardwood (KD Hardwood)

Most kiln dried hardwood you purchase off the shelf in Australia will be Alpine Ash or Mountain Ash and rated at F17.

KD hardwood benefits:

  • Longer durability than treated pine if well maintained.
  • Higher strength rating (longer spans in building).
  • Visually beautiful if staining.

KD hardwood cons:

  • More expensive than treated pine.
  • Heavier than treated pine.
  • Slightly more difficult to work with for the DIY builder.

Hardwood strength rating ranges from F17 to F34. For further information on this visit timber ratings guide.

Other Hardwoods

Typically other hardwoods are only used if requiring some type of exposed or feature timber.

Apart from being cost prohibitive, other types of hardwood in many instances may be difficult to source.

For instance, we did complete a job where we used all merbau for the frame. Just as a price difference, the current price for a 140×45 rafter would be:

  • Treated pine – $11 per lineal metre.
  • KD hardwood – $19 per lineal metre.
  • Merbau – $52 per lineal metre.
  • Blackbutt – $55 per lineal metre.