Collection: Silvertop Ash Timber

 
Silvertop Ash (
Eucalyptus sieberi), also known as "Coast Ash," is a moderately durable hardwood native to the southern and central coastal regions and tablelands of New South Wales, eastern Victoria, and northeastern Tasmania. This large Australian hardwood thrives in cooler, coastal environments, where it has earned a reputation for both strength and fire resistance.

 

Appearance

Silvertop Ash features a medium texture with an interlocked grain, highlighted by its distinctive growth rings. Its heartwood ranges from brown to a soft pinkish hue, while the narrow sapwood may not always be easily distinguishable. Characterized by the presence of gum veins, pinhole borer markings, and subtle pencil streaks, Silvertop Ash showcases a unique visual appeal that adds warmth and character to any project.

Common Applications

Silvertop Ash is valued as a versatile building timber, particularly suited for timber framing and structural applications along the NSW south coast and tablelands. Its natural durability and fire-resistant properties make it one of the seven hardwoods approved by the Building Commission in Victoria for use in bushfire-prone areas, provided it has a thickness of over 18mm. Beyond construction, Silvertop Ash is commonly used in flooring, furniture, high-end joinery, vehicle construction, fence posts, and handles. Additionally, it is utilized in packaging and chemical pulp manufacturing.

Workability

Silvertop Ash offers reasonable workability and is compatible with most woodworking tools. It machines well, is easy to nail and screw, and accepts a wide range of coatings. Though prone to splintering, it sands smoothly and is excellent for steam bending. Historically, the wood’s splitability made it a favorite among pioneers for roof shakes, as it easily splits along the rays. However, care should be taken when drying Silvertop Ash, as it is prone to surface checking on the tangential surface and dries at a slower rate.

Origin and Availability

Kosny Timber sources Silvertop Ash from sustainably managed native forests across New South Wales, Victoria, and Tasmania. Readily available throughout Australia, this timber provides both strength and resilience, ideal for projects requiring a moderately durable hardwood with a unique visual appeal.

 Very LowLowMediumHighVery High
   Check markCheck markCheck mark
Tangential :    10.60%
Radial :    5.70%
Unit Movement Tangential:   0.36% 
Unit Movement Radial:  0.25%  

Very High

High

Reasonably High

Medium High

Medium

Reasonably Low

Low

Very Low

Unseasoned:

S1

S2

S3

S4

S5

S6

S7

S8

Check mark

Seasoned:

SD1

SD2

SD3

SD4

SD5

SD6

SD7

SD8

Check mark
 Structural
No. 1
Structural
No. 2
Structural
No. 3
Structural
No. 4
Structural
No. 5
Unseasoned:F17F14F11F8F7
Seasoned:F27F22F17F14F11
Seasoned:

 

850kg/m3

 

Unseasoned:

 

1100kg/m3

 

 Very HighHighReasonably HighMediumLowVery Low
Unseasoned:J1J2J3J4J5J6
 Check mark    
Seasoned:JD1JD2JD3JD4JD5JD6
 Check mark    
 White, yellow, pale straw to light brownPink to pink brownLight to dark redBrown, chocolate, mottled or streaky
  
Check mark
Modulus of Rupture - Unseasoned:78 MPa
Modulus of Rupture - Seasoned:137 MPa
Modulus of Elasticity - Unseasoned:13.2 GPa
Modulus of Elasticity - Seasoned:17.3 GPa
Maximum Crushing Strength - Unseasoned:41.6 MPa
Maximum Crushing Strength - Seasoned:75 MPa
Impact - Unseasoned:19.5 J
Impact - Seasoned:20.3 J
Toughness - Unseasoned:Medium - 15 - 24 Nm
Toughness - Seasoned:Medium - 15 - 24 Nm
Hardness - Unseasoned:6.7
Hardness - Seasoned:9.7
 LowModerateReasonably HighHigh
 (0 - 5 yrs)(5 - 15 yrs)(15 - 25 yrs)(more than 25 yrs)
In-Ground:>Check mark  
 (0 - 7 yrs)(7 - 15 yrs)(15 - 40 yrs)(More than 40 yrs)
Above ground: Check mark 
 (0 - 20 yrs, usually < 5)(21 - 40 yrs)(41 - 64 yrs)(More than 60 yrs)
Marine Borer Resistance:>Check mark   
Lyctid Borer Susceptibility:Not Susceptible
Lyctid Borer Susceptibility - Other: 
Termite Resistance:Not Resistant
 012345678910
EFH Spread-of-Flame Index:         
EFH Smoke-Developed Index:          
Critical Radiance Flux - Lower:>2.2 and <4.5
Critical Radiance Flux - Higher:>2.2 and <4.5
Smoke Development Rate:<750
1 - non-combustible2 - reasonably non-combustible3 - slightly combustible4 - combustible

Fire Properties Group
Number:

Average Specific Extinction Area:<250
Bushfire Resistance:Bushfire Attack Level (BAL) 12.5, 19 and 29 - All AS 3959 Required Applications