Silvertop Ash Decking NOW at NHS!

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Eucalyptus Sieberi

Silvertop Ash is a beautiful Australian Hardwood that is light honey brown/blonde with pinkish tones which is similar in colour to Blackbutt.

It is one of the seven hardwood species that has been found to be suitable for homes built in bushfire prone areas with a BAL29 rating.

Silvertop Ash is a visually striking timber with natural features like gum veins, growth rings, ambrosia pinhole borer markings and fire/pencil streaks.  It has a Class 2 above ground durability, hardness rating of  9.5, making it a desirable option.

Silvertop Ash grows in the southern and central coast of New South Wales, the eastern Victoria and north-eastern Tasmania regions and has been successfully and sustainably harvested for decades.  It is generally found in decking, flooring and shiplap cladding.

There are a couple of things to be mindful of when comparing to Blackbutt 19mm thick decking…

Different grade

Silvertop Ash decking is graded as ‘Run of Mill’ whereas Blackbutt is generally graded ‘Standard and Better’.

‘Run of Mill’ grade is a term used to include the natural mix of grades from the production run which includes Feature, Standard, and Select.

‘Standard and Better’ grade contains natural features and surface checking that are permissible in Standard grade as well as any timber that is better than standard grade so can contain Select grade boards.

Run of Mill grade therefore contains more natural features and surface checking than Standard and Better grade.

Run of Mill grade generally has a better average length mix compared with Standard and Better grade and is more cost effective.

As Silvertop Ash decking is graded as Run of Mill it contains more natural features and surface checking that you would expect in Blackbutt.

Profile & thickness

  • The Silvertop Ash profile is 2 Pencil Round edges and square bottom making only 1 face available and not reversible.  Blackbutt, in comparison, has 4 pencil round edges so both sides can be used.
  • Silvertop Ash decking is 22mm thick whereas the Blackbutt is 19mm.  Please allow for this extra thickness in calculating clearances.


Blackbutt and Silvertop Ash are similar in colour as they are both classed as blonde timbers. Silvertop Ash tends to also have pinkish tones and black pin hole and black fire or pencil streaks (more details about this below).


Blackbutt and Silvertop Ash have similar natural features.  Silvertop Ash tends to get a black ring around pin holes which is caused by the ambrosia beetle as well as black fire or pencil streaks which can look like surface checking.  These are natural features of the timber.


  • Blackbutt: Class 2 in ground, Class 1 above ground
  • Silvertop Ash: Class 3 in ground, Class 2 above ground

Prone to surface checking

Pre-oil Silvertop Ash as it is more susceptible than some other species to surface checking. Re-oil as per the manufacturer’s instructions.

Both are Fire Resistant – BAL29 (Very resistant)

Silvertop Ash is worth considering for your next deck as a cost-effective alternative to Blackbutt.  Keep in mind to expect more natural features, pre-oil as recommended and an increased board thickness.

Now in stock at NHS is the Silvertop Ash Decking in 90x22mm run of mill grade.