{"product_id":"iron-bark-timber-decking","title":"Iron Bark Decking","description":"\u003cp\u003eGrey ironbark decking in 86 × 19 mm and 135 × 19 mm: one of the hardest Australian hardwoods, with Janka hardness 16 kN, Class 1 durability both above ground and in-ground, and rated for bushfire decking up to BAL-19.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSizes:\u003c\/strong\u003e 86 × 19 mm and 135 × 19 mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTimber:\u003c\/strong\u003e grey ironbark (\u003cem\u003eEucalyptus paniculata\u003c\/em\u003e and \u003cem\u003eE. drepanophylla\u003c\/em\u003e), grown in NSW and Queensland; reddish-brown to dark brown; about 1105–1120 kg\/m³, the densest timber in our decking range\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDurability:\u003c\/strong\u003e Class 1 above ground, which the Queensland Government rates at more than 40 years’ expected life; Class 1 in-ground too; the heartwood is termite resistant and the sapwood isn’t susceptible to lyctid borer\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBushfire:\u003c\/strong\u003e qualifies under AS 3959’s high-density rule for BAL-12.5 and BAL-19, but it is not on the bushfire-resisting timber list, so it can’t be used for decking at BAL-29. For BAL-29, choose Spotted Gum, Blackbutt or Merbau\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eJoist spacing:\u003c\/strong\u003e 450 mm centres, as WoodSolutions recommends for decking; its deck design guide allows up to 500 mm for 19 mm hardwood, or 350 mm if the boards run at 45°\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eGaps:\u003c\/strong\u003e 3–4 mm between 86 mm boards and 4–5 mm between 135 mm boards at installation (WoodSolutions deck design guide)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHow much for a deck:\u003c\/strong\u003e a 20 m² deck needs about 140 lineal metres of 135 mm board or about 225 lineal metres of 86 mm, plus about 10% for offcuts\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLow decks:\u003c\/strong\u003e under 400 mm off the ground, WoodSolutions suggests 5–6 mm gaps and at least 40 mm between the deck and the house, for airflow\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFixing:\u003c\/strong\u003e two fixings per board at every joist, at least 12 mm from edges and ends. Pre-drill this dense hardwood. Use stainless steel within 1 km of the coast or 1 m of a pool. See our \u003ca href=\"\/collections\/decking-accessories\"\u003edecking screws\u003c\/a\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFinishing:\u003c\/strong\u003e coat every face and cut end, ideally before fixing, then recoat at least once a year or as the oil maker directs (WoodSolutions); left bare, it weathers to silver-grey. Oils we stock: \u003ca href=\"\/products\/cutek-oil-extreme-cd50\"\u003eCUTEK CD50\u003c\/a\u003e, \u003ca href=\"\/products\/intergrain-universal-timber-oil\"\u003eIntergrain Universal Timber Oil\u003c\/a\u003e or \u003ca href=\"\/products\/sceneys-timber-decking-oil\"\u003eSceney’s Timber Decking Oil\u003c\/a\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAt Greenhill:\u003c\/strong\u003e stocked at 170 Settlement Road, Thomastown, with pickup or delivery across Melbourne and regional Victoria. Compare species on our \u003ca href=\"\/collections\/timber-decking\"\u003ehardwood decking\u003c\/a\u003e page.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eGrey ironbark decking: sizes, lengths and prices\u003c\/h2\u003e\n\u003ctable class=\"ght-sizes\"\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eSize\u003c\/th\u003e\n\u003cth\u003eLengths\u003c\/th\u003e\n\u003cth\u003ePrice\u003c\/th\u003e\n\u003cth\u003eAvailability\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e135 × 19 mm\u003c\/td\u003e\n\u003ctd\u003eRandom length\u003c\/td\u003e\n\u003ctd\u003e$15.90 per lineal metre\u003c\/td\u003e\n\u003ctd\u003ein stock\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e86 × 19 mm\u003c\/td\u003e\n\u003ctd\u003eRandom length\u003c\/td\u003e\n\u003ctd\u003e$10.62 per lineal metre\u003c\/td\u003e\n\u003ctd\u003ein stock\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003eSold in random lengths, cut to suit. Prices are our website prices on 14 October 2026, per lineal metre; a 20 m² deck needs about 140 lineal metres of 135 mm board or 225 of 86 mm, plus 10% for cuts.\u003c\/p\u003e\n\u003ch2\u003eWhat Grey ironbark decking is like\u003c\/h2\u003e\n\u003cp\u003eGrey ironbark, mainly \u003cem\u003eEucalyptus paniculata\u003c\/em\u003e with \u003cem\u003eE. drepanophylla\u003c\/em\u003e and \u003cem\u003eE. siderophloia\u003c\/em\u003e, is the heaviest timber in our decking range at about 1,106 kg\/m³ seasoned, and the hardest: WoodSolutions gives a seasoned hardness of 16 kN, roughly double Merbau. The colour is light grey to light chocolate with darker red and brown boards mixed through, and the grain is interlocked and dull rather than figured.\u003c\/p\u003e\n\u003cp\u003eDurability is Class 1 both above ground and in the ground, which is why the same timber is sold as posts and bridge timber. The heartwood is termite resistant and the sapwood is not susceptible to lyctid borer, so there is little that needs to be cut out of a pack.\u003c\/p\u003e\n\u003ch2\u003eWhere it suits\u003c\/h2\u003e\n\u003cp\u003eThis is the board for decks that get punished: commercial walkways, pool surrounds, shaded decks that stay damp, anywhere a dropped tool or a dragged chair would mark a softer timber. The limit is bushfire: grey ironbark qualifies under the AS 3959 density rule for BAL-12.5 and BAL-19 but is not on the bushfire-resisting timber list, so it cannot be used for decking at BAL-29. For BAL-29 choose Spotted Gum, Blackbutt or Merbau.\u003c\/p\u003e\n\u003ch2\u003eFixing and finishing\u003c\/h2\u003e\n\u003cp\u003ePre-drill everything and expect to replace drill bits; at 16 kN the timber blunts tools quickly. Two stainless or Class 3 galvanised screws per board per joist, 450 mm joist centres, 4–5 mm gaps on the wide board. Being so dense it takes oil slowly, so apply thin coats of \u003ca href=\"\/products\/cutek-oil-extreme-cd50\"\u003eCUTEK Extreme CD50\u003c\/a\u003e or \u003ca href=\"\/products\/intergrain-universal-timber-oil\"\u003eIntergrain Universal Timber Oil\u003c\/a\u003e and wipe off the excess. Screws are in \u003ca href=\"\/collections\/decking-accessories\"\u003edecking accessories\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch2\u003eThe same timber for other jobs\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003ca href=\"\/products\/grey-ironbark-timber-flooring\"\u003eGrey Ironbark solid floorboards\u003c\/a\u003e – 130 × 14 mm Feature grade in stock, other sizes ordered in\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/products\/iron-bark-timber-cladding\"\u003eIronbark cladding\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"\/collections\/timber-decking\"\u003eHardwood decking\u003c\/a\u003e – all six species side by side\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eCompare the species\u003c\/h2\u003e\n\u003cp\u003eOur \u003ca href=\"\/blogs\/guides\/decking-timber-comparison-melbourne\"\u003edecking timber comparison\u003c\/a\u003e puts hardness, durability, bushfire rating and price per metre for all six hardwoods on one page; \u003ca href=\"\/collections\/merbau\"\u003eMerbau decking\u003c\/a\u003e is the budget alternative.\u003c\/p\u003e\n\u003ch2\u003eQuestions we get asked\u003c\/h2\u003e\n\u003ch3\u003eHow much does ironbark decking cost?\u003c\/h3\u003e\n\u003cp\u003eOn our website on 14 October 2026, 86 × 19 mm is $10.62 per lineal metre and 135 × 19 mm $15.90 per lineal metre, the same price per metre as Grey Box and below Blackbutt in the wide board.\u003c\/p\u003e\n\u003ch3\u003eIs ironbark the hardest decking timber?\u003c\/h3\u003e\n\u003cp\u003eOf the species we stock, yes: 16 kN seasoned hardness against 15 for Grey Box, 10.1 for Spotted Gum and 8.5 for Merbau.\u003c\/p\u003e\n\u003ch3\u003eCan I use it at BAL-29?\u003c\/h3\u003e\n\u003cp\u003eNo. It is not on the AS 3959 bushfire-resisting timber list, so it stops at BAL-19 for decking, which it meets on density.\u003c\/p\u003e\n\u003ch3\u003eIs it red or grey?\u003c\/h3\u003e\n\u003cp\u003eBoth come through in a pack: light grey and light chocolate boards with some darker red-brown ones. Oiled, the mix evens out.\u003c\/p\u003e\n\u003ch3\u003eWhy is it harder to lay?\u003c\/h3\u003e\n\u003cp\u003eWeight and density. A 5.4 m 135 × 19 board is about 15 kg, every screw needs a pilot hole, and saw blades dull faster.\u003c\/p\u003e\n\u003ch2\u003ePickup and delivery\u003c\/h2\u003e\n\u003cp\u003eStocked at 170 Settlement Road, Thomastown, Mon–Fri 7 am–4:30 pm and Sat 9 am–1 pm. We pack and load it for you, or deliver across Melbourne and regional Victoria; delivery is quoted with the order. Call (03) 9465 9875 with your sizes and we will work out the lineal metres and the price.\u003c\/p\u003e\n","brand":"Greenhill Timbers","offers":[{"title":"135 x 19mm","offer_id":68913571004450,"sku":"GHT-9802","price":15.9,"currency_code":"AUD","in_stock":true},{"title":"86 x 19mm","offer_id":68913571037218,"sku":"GHT-9801","price":10.62,"currency_code":"AUD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0917\/3981\/5970\/files\/Ironbark.jpg?v=1792367718","url":"https:\/\/greenhilltimbers.com.au\/products\/iron-bark-timber-decking","provider":"Greenhill Timbers","version":"1.0","type":"link"}