Design XLam CLT to AS 1720.1

XLam manufactures cross laminated timber at Wodonga, Victoria, from Australian plantation radiata pine, and has supplied the Australian, New Zealand and Pacific markets since 2012. The panels are not covered by a European Technical Assessment or an ICC-ES report. SPEC Toolbox designs them to AS 1720.1, using the values declared in the XLam CLT Panel Product Data Sheet.

The integration covers sixteen XLam CLT panel layups, built from finger-jointed radiata pine lamellas laid at 90 degrees to one another and bonded with a moisture-cured polyurethane adhesive.

• Three, five and seven layer layups, CL3/90 through CL7/310, at element thicknesses of 90 to 310 mm.
• Two lamella grades, XGP1 in the outer layers and XGP2 in the inner layers, from lamellas 20 to 45 mm thick. Mean density 500 kg/m3 at 12 percent moisture content.
• Panels up to 3.4 m wide and 15.7 m long, made to order from project shop drawings. The seven layer panels also cover band beam applications 600 to 1700 mm wide.
• Thickness, width and length tolerance plus or minus 2 mm, lamella thickness plus or minus 1 mm. Lamellas are not edge glued.
• PEFC chain of custody (SCS-PEFC/COC-05795) and a published Environmental Product Declaration (S-P-02326).

At a glance, in the ANZ scope the XLam CLT panels support:

• Load-bearing walls, floors and roofs, and the stairs, soffits and balconies set out in the data sheet.
• Service classes 1 and 2 as defined in AS/NZS 4364:2010.
• Industrial or natural surfaces, with CNC machining and angled cuts.

• Declared lamella values. The data sheet declares a modulus of elasticity of 10 000 MPa for XGP1 and 6 000 MPa for XGP2, a rolling shear strength of 1.4 MPa for both grades, and rolling shear moduli of 45 and 29 MPa, which carry directly into the panel section properties.
• Long panels produced inside the region. Panels reach 3.4 m wide and 15.7 m long from the Wodonga plant and are transported at that size across Australia, New Zealand and the Pacific, widening the joint pattern available for long floor spans and full-storey walls.
• One tolerance across all three dimensions. Thickness, width and length are each held to plus or minus 2 mm, and lamella thickness to plus or minus 1 mm, which helps connection detailing and dimensional coordination.
• Treated panel option from the feedstock supplier. Panels are supplied untreated or with Hyne T3 Plus treatment against mould and termite attack, from Hyne, XLam’s sister company and feedstock supplier. The treatment does not increase the corrosion risk to fixings.
• Formaldehyde-free bond and documented carbon. The Henkel Purbond Loctite HBS polyurethane bond line is formaldehyde free, with emissions below 0.1 mg/m2/hr to ASTM D5116:2017. The panels carry a global warming potential of minus 492 kg CO2-eq per m3, and Declare Red List Free status treated or untreated.

The XLam CLT panels are available across the SPEC Toolbox CLT modules, worked to AS 1720.1:

• CLT floor, CLT wall, CLT shear wall, CLT diaphragm and CLT floor penetration.

and in the connection modules:

• the screw connection module and the panel-to-panel connection details (spline, butt joint and half-lap);
• CLT floor-to-glulam beam, CLT floor-to-floor and CLT wall-to-wall connections.

Panel behaviour is taken from the integrated database with the exact declared values of the XLam product data sheet, and the same values are used for design to the Australian and New Zealand standards. Fire design, vibration and other verifications not covered by the current Eurocode 5 can be checked against the new Eurocode 5 and other relevant documentation.

Design follows AS 1720.1, and NZS AS 1720.1:2022 in New Zealand. Neither AS 1720.1 nor NZS 3603 covers cross laminated timber, so XLam treats CLT as a performance solution: the strength and serviceability checks follow AS 1720.1, while the section properties come from the layup and the rolling shear behaviour of the cross layers. XLam derives its span tables with the shear analogy method and applies the j2 duration of load factor to long-term deflection. The characteristic strengths, the moduli of elasticity and shear, and the mean density are those declared in the product data sheet, which covers service classes 1 and 2. Resistance to fire is established by AS 1530.4 testing and assessment rather than from the panel values.