Triplochiton scleroxylon
Truwood
Also known as: Thermally Modified Ayous
Timber GrainAbout this Timber
General Description
Truwood is a thermally modified, clear grade, low density hardwood produced from a timber called Ayous. The thermal treatment provides a rich teak-coloured timber that is durable and stable - naturally, without any chemical treatment, resins or glues.
As with most materials, thermally treated timber is unable to resist the effects of ultraviolet radiation. Over a fairly short period of time when exposed to direct sunlight, the colour will fade from the original mid-brown appearance to a grey weathered colour. UV radiation can also cause small surface checks to occur, as with any timber. It is recommended to apply a pigment-based surface protector to prevent this.
Working Properties
How This Timber Works
The wood works well with hand or machine tools. It glues, nails, screws, stains and takes paint and stain well, and can be brought to an excellent finish.
Mechanical Properties
Truwood is very stable due to the modification process. Since the cell structure of modified wood absorbs less water, the equilibrium moisture content of the timber is also reduced. Improved dimensional stability reduces movement in service such as cupping, as well as splitting and checking around fixings. The modification process slightly lowers the density and has some effects on strength values, comparable to Western Red Cedar. The modification process also causes the timber to be more brittle - extra care is required in handling.
Technical Data
Technical Specifications
*Air Dry Density (kg/m³) is an average indication only and actual values may vary. Refer to strength, shrinkage and durability classification tables for full details.
Reference Tables
Timber Classification Tables
Standard NZ classification tables for strength groupings, shrinkage and durability. This species is highlighted in each table.
| Strength Group | Modulus of Rupture | Modulus of Elasticity | Max Crushing Strength |
|---|---|---|---|
| S1 | 103 | 16300 | 52 |
| S2 | 76 | 14200 | 43 |
| S3 | 73 | 12400 | 36 |
| S4 | 62 | 10700 | 31 |
| S5 | 52 | 9100 | 26 |
| S6 | 43 | 7900 | 22 |
| S7 | 36 | 6900 | 18 |
| Strength Group | Modulus of Rupture | Modulus of Elasticity | Max Crushing Strength |
|---|---|---|---|
| SD1 | 150 | 21500 | 80 |
| SD2 | 130 | 18500 | 70 |
| SD3 | 110 | 16000 | 61 |
| SD4 | 94 | 14000 | 54 |
| SD5 | 78 | 12500 | 47 |
| SD6 | 65 | 10500 | 41 |
| SD7 | 55 | 9100 | 36 |
| SD8 | 45 | 7900 | 30 |
| Description of Shrinkage | Tangential | Radial |
|---|---|---|
| Very Low | 0 – 3.5 | 0 – 2 |
| Low | 3.5 – 5.0 | 2 – 3 |
| Medium | 5.0 – 6.5 | 3 – 4 |
| High | 6.5 – 8.0 | 4 – 5 |
| Very High | > 8.0 | > 5 |
| Grade of Durability | Fully Protected | Above Ground, Exposed | In-Ground, Exposed |
|---|---|---|---|
| Very Durable | > 50 | > 40 | > 25 |
| Durable | > 50 | 15 – 40 | 15 – 25 |
| Moderately Durable | > 50 | 7 – 15 | 5 – 15 |
| Non-Durable | > 50 | 0 – 7 | 0 – 5 |
Applications
Main Uses
Stock & Sizes
Availability
Wide range of 19mm thick vertical and horizontal weatherboard profiles, in accordance with NZS3617 and Branz Bulletin 411, compatible with all standard cladding system details. Also available in 50mm thicknesses in fixed widths of 50, 100, 150 and 200mm.
Quality Standard



