By the Sydney Timber Supply team
Blackbutt (Eucalyptus pilularis) is one of the most popular Australian hardwoods for decking, and for good reason. Supplier specification sheets rate it Class 1 for above-ground durability with a service life of 40+ years, it carries a BAL 29 bushfire rating per the supplier flyer (AS3959-2009), and its straight grain and creamy blonde to honey tones suit modern and traditional homes alike. Sydney Timber Supply stocks Blackbutt decking in 86 x 19 mm and 135 x 19 mm, sold per linear metre. You can browse the range at our Blackbutt collection.
What Blackbutt looks like
Blackbutt has a straight grain and an even texture, which gives decks a clean, consistent appearance. Colour runs from creamy blonde through to rich honey tones, so it pairs well with light renders, timber cladding and coastal palettes. If you want to compare it against other species side by side, our species guide covers the full Australian hardwood range we stock.
Durability: what Class 1 actually means
Class 1 is the highest natural above-ground durability class for timber. Supplier specification sheets rate Blackbutt as Class 1 above ground with a 40+ year service life, which puts it in the same durability class as Ironbark, Spotted Gum, Redgum and Gympie Messmate. At Sydney Timber Supply we only show the Class 1 badge on hardwoods whose supplier specification sheets state it, so when you see it on Blackbutt, that claim comes straight from the published documentation.
It is also a hard timber, which matters on a deck that will see furniture, foot traffic and the occasional dropped tool.
Bushfire rating: BAL 29
Per the supplier flyer, Blackbutt is rated for use in bushfire-prone areas up to BAL 29 under AS3959-2009. That makes it a practical choice for many properties on the Central Coast and in bushfire-affected parts of NSW where decking material selection is restricted. Always confirm the BAL requirement for your specific site with your certifier or council before ordering.
Sizes and coverage at Sydney Timber Supply
We stock Blackbutt decking in two profiles, both sold per linear metre (LM) in random lengths, with preferred lengths available by quote.
| Profile | Coverage width (board + gap) | Typical use |
|---|---|---|
| 86 x 19 mm | 90 mm | Classic narrow-board deck look |
| 135 x 19 mm | 139 mm | Wide-board contemporary decks |
Coverage width is the board face plus the gap between boards. WoodSolutions deck design guidance suggests typical gaps of 3 to 6 mm.
Working out how much you need
The maths is simple: divide your deck area by the coverage width in metres. For example, a 20 m2 deck in 86 mm boards with a 4 mm gap works out at 20 / 0.090 = 222.2 LM. We recommend adding a 10% waste allowance for cuts and docking. To get a board count, divide total LM by the board length (for example 5.4 m boards).
Rather than doing it by hand, use our timber calculator: enter your area, board width and gap and it does the linear metres, waste allowance and board count for you.
Installation basics
The supplier's decking handling and installation guidelines (attached on our product pages) set out the key numbers:
- Maximum joist spacing of 450 mm centres
- Minimum ground clearance of 400 mm for ventilation under the deck
- Fixings a minimum of 12 mm from board ends and edges
Good subfloor ventilation and correct fixing distances do a lot of the work in keeping a hardwood deck flat and tight over its life. Read the supplier guide in full before you start, and follow your fastener manufacturer's directions.
Caring for a Blackbutt deck
Care is straightforward and generic good practice applies:
- Sweep regularly and wash down periodically to remove dirt and organic build-up.
- Keep the underside ventilated; do not block airflow with stored goods or garden beds hard against the deck.
- If you choose to oil or coat the deck, follow the finish manufacturer's directions for preparation and recoat intervals.
- Expect the colour to weather over time if left uncoated; regular maintenance keeps the timber looking its best.
FAQ
Is Blackbutt an Australian hardwood?
Yes. Blackbutt (Eucalyptus pilularis) is an Australian hardwood, and it sits within our Australian hardwood range alongside Ironbark, Spotted Gum, Redgum and Gympie Messmate.
What sizes does Sydney Timber Supply stock?
Blackbutt decking in 86 x 19 mm and 135 x 19 mm, sold per linear metre in random lengths. Preferred lengths are available by quote.
Can I use Blackbutt in a bushfire-prone area?
Per the supplier flyer, Blackbutt is BAL 29 rated under AS3959-2009. Confirm your site's specific BAL requirement with your certifier before ordering.
How do I buy it?
Order per linear metre through the decking collection, or request a quote for packs, preferred lengths or bulk quantities.
Talk to us
Sydney Timber Supply is at 12 Dyer Crescent, West Gosford, with pickup available and delivery across Sydney, the Central Coast, Newcastle and the Hunter, and Wollongong and the Illawarra (see delivery and pickup). For pack pricing, preferred lengths or a full decking take-off, request a quote or call 0440 137 068.
Technical details drawn from supplier specification sheets; reviewed 19 July 2026.