Timber Species Truwood

Triplochiton scleroxylon

Truwood

Also known as: Thermally Modified Ayous

Region of Origin: West Africa
Vertical CladdingHorizontal CladdingBevel BackBoard & BattenInternal PanellingSoffitsFencingScreensWindow FramesDoorsLouvresGatesInterior Joinery
Density
350 kg/m³
Durability
Durable
Janka
1.3 kN
Strength Group
SD8
Truwood timber grainTimber Grain
NZS3617 Compliant

About 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

Density
350kg/m³
Air dry density (avg)
Durability Class
Durable
Strength Group
SD8
Structural classification
Janka Hardness
1.3kN
Surface hardness rating
MOR — Modulus of Rupture
40
Seasoned MPa
MOE — Modulus of Elasticity
6.0
Seasoned GPa
Shrinkage — Green to 12% Moisture Content
1.9%
Tangential
1.5%
Radial
Dimensional change from green timber to 12% moisture content
Compliance
NZS3617 Compliant
Vertical, Horizontal, Bevel Back & Board and Batten systems

*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.

Minimum Values for Strength Groups
Unseasoned Timber  |  Units: MPa = 145 lb/sq.inch
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
Minimum Values for Strength Groups
Seasoned Timber  |  Units: MPa = 145 lb/sq.inch
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
Shrinkage Classifications
Shrinkage from Green to Oven-dry (12% MC) – % before reconditioning
Description of Shrinkage Tangential Radial
Very Low0 – 3.50 – 2
Low3.5 – 5.02 – 3
Medium5.0 – 6.53 – 4
High6.5 – 8.04 – 5
Very High> 8.0> 5
Durability Classifications
Approximate service life (years)
Grade of Durability Fully Protected Above Ground, Exposed In-Ground, Exposed
Very Durable> 50> 40> 25
Durable> 5015 – 4015 – 25
Moderately Durable> 507 – 155 – 15
Non-Durable> 500 – 70 – 5
This species – Strength Group
SD8
Highlighted in the strength tables above
This species – Durability
Durable
Highlighted in the durability table above

Applications

Main Uses

Vertical Cladding Horizontal Cladding Bevel Back Board & Batten Internal Panelling Soffits Fencing Screens Window Frames Doors Louvres Gates Interior Joinery

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

Grading

Grade Select