Timber frame building is favoured in Australia. The wall studs are the vertical members in a wall frame and can be sub-MGP grades high stiffness.

Timber frame building is favoured in Australia. The wall studs are the vertical members in a wall frame and can be sub-MGP grades high stiffness.

By Joy Crane

Geographical proximity and the similarity of its pine resource make South Africa a compelling alternative supplier of softwood timber to Australia. In 2020-21 Australia imported 66,3% of its softwood supplies from Europe, increasing the risk of aggravating its developing shortfall of structural timber.

“Australia offers many opportunities for South African sawn timber because of our looming resource challenge. As of 29 September 2021, the country faces a timber deficit of 250,000 house frames by 2035,” said Toby James, the general manager of Staxa. Staxa is the marketing arm of the largest sawn timber supplier in Western Australia, Wespine.

Sawmilling South Africa (SSA) hosted James and Wespine’s technical director, Richard Schaffner, during their whirlwind tour of the South African structural timber mills. Their visit follows promising results from Wespine’s testing of four container loads of S5 SA pine.

Schaffner and James wanted to understand better South Africa’s saw-log resources, standard structural sizes, and the sawmilling, treating and value-adding processes. They attended the SSA AGM in Pretoria in June and used the opportunity to provide a brief overview of the Australian sawmilling sector and their company, Wespine.

Wespine is a softwood sawmill backed by two Australian Stock Exchange listed companies, Wesfarmers, which owns Bunnings Warehouse, and Fletcher Building, which owns Laminex. The holding companies provide strong financial backing and national distribution channels.

 

Dardanup sawmill.

Dardanup sawmill.

Timber frame building

Unlike southern Africa, timber framing is the dominant home building system. James says one house consumes about 14m3 of finished timber, and around half is in the wall frame and the rest in the roof. Roughly 140,000 timber frame houses are built each year.

“Australia’s resource self-sufficiency appears to be out of reach with projected demand,” explained James. “We will need an additional 468,000 hectares of softwood plantations before 2050. However, there is significant competition for land use, and the Australian softwood plantation estate has not expanded for almost three decades.”

James believes imports are vital to supply the projected shortfall of 2,062-million m3 sawn softwood per year before 2050, “assuming there is no substitution by, for example, steel”.

 

Average Australian sawmill

Only eight companies own the 13 largest sawmills in Australia. The mills consume 86% of the country’s sawlogs at an average of 480 000m3 per annum. The softwood sawmills, including Wespine’s Dardanup sawmill, are concentrated in the southeast.

Sawmills draw unpruned sawlogs from forests between 20km and 300km from the mill. “Pruning was popular about 30 years ago, but today it is uncommon in Australia because of high labour costs. The silvicultural regime is geared for structural timber, not clears,” said Schaffner.

Most mills are automated because of the massively high labour and general operating costs. Drying is mainly by batch kilns; however, continuous kilns are entering the industry.

The sawmills employ an average of between 180 and 200 people. A process worker earns an average of R50,000/month and a tradesperson about R100,000/month.

 

Structural softwood

The three primary timber  market segments in Australia are:

  • Structural
  • Outdoor
  • Packaging

The country has very specific regulatory requirements. Structural softwood must comply with the grading standard AS/NZS 1748:2006 mechanically stress-graded for structural purposes, also known as MGP (machine-graded pine).

MGP sawmills must:

  • Qualify their grading method
  • Verify every batch of production – enforced by an auditor
  • Perform an annual review of grading effectiveness.

 

Preservation

The Australian standards do not tolerate heartwood in structural materials. Schaffner said that based on its primary market segments, a typical sawmill produces:

Ex-wetmill

  • Heart-in material: 25%-30% for packaging and landscaping
  • Heart-free sapwood: 70-75% kiln dried and graded for MGP in the drymill

Ex-drymill

  • Volume recovery: 85%+ into MGP grades
  • Remainder: Rejected and used in non-structural applications

“Consumer law obligates the producer to demonstrate compliance due diligence to ensure products are free from false claims and generally fit for purpose,” explained Schaffner.

 

Wespine

Wespine’s drymill is automated with in-line machine grading for MGP. It uses the Metriguard 7200 HCLT to measure an area of each board as a strength predictor. The information combines with surface scan data from the USNR linear high grade (LHG) scanner that develops and executes optimised cross-cut decisions to maximise value recovery.

A sophisticated quality control sampling and testing regime gives feedback in real-time, letting the mill react when there are deviations.

Wespine also produces proprietary grades or F-grades according to the visual grading standard AS2858. Proprietary grades enable value recovery from fibre that does not achieve the MGP standard. The country consumes large volumes of products like wall framing studs where lower F-grade structural properties are suitable.

“We saw quite a lot of finger-jointing on our tour. Australia’s structural rules do not accommodate finger-jointed timber. It is labour intensive, and there is no sawmill with enough wood to justify finger-jointing,” Schaffner commented.

 

Road map to export

“We would like to buy your products. The proprietary and MGP grades are of higher value, but they also have high technical specifications and require investment to develop capacity.

“The immediate opportunity for most South African mills lies in sub-MGP products. There are three immediate product opportunities: non-structural treated, F-grades, and F-grades treated timber. Over time we can scale through to MGP and appearance grade products.

 

The three immediate export product opportunities’

 

“Like us, you focus on recovering the outer part of butt logs for high volume and high-value production and won’t want to export it. Maybe the second log will offer us more opportunities leaving you with structural sizes with-heart that work for you and side-boards that suit us better?”

 

Schaffner suggested that South African mills consider a side-boards only product-specific cutting pattern or whole log production in Australian sizes.

 

Option 1 - Whole log 150-200mm centre cant for CCA fence palings and sleepers.

Option 1 – Whole log 150-200mm centre cant for CCA fence palings and sleepers.

The whole log 

  • 150-200mm centre cant
    • CCA sleepers (50x200mm) ungraded non-structural applications with heartwood.
    • CCA fence palings
  • High-density side-boards
    • 25mm x75, 100, 150mm
    • 35mm x70, 90, 120, 170, 190mm
    • 45mm x70, 90, 140, 190mm
    • F7 visual grade
    • Proprietary grades
    • Untreated, CCA, (light organic solvent preservative) LOSP

 

Option 2 – Cant cut for SA specifications and high density side boards cut to Australian dimensions.

Side-boards only

  • Centre cant cut for South African applications
  • High-density side-boards cut to Australian dimensions

 

We are optimistic that some of the millers we met will supply us with timber,” Schaffner and James said.