{"product_id":"greybox-timber-decking","title":"Greybox Decking","description":"\u003cp\u003eGrey Box decking in 86 × 19 mm and 135 × 19 mm: one of the hardest, most durable Australian decking timbers, with Janka hardness 15 kN and Class 1 durability both above ground and in-ground, 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 in random lengths\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTimber:\u003c\/strong\u003e Grey Box (\u003cem\u003eEucalyptus moluccana\u003c\/em\u003e), grown from Jervis Bay in NSW to the Atherton Tableland; usually pale brown, sometimes yellowish; about 1105 kg\/m³\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\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 Box 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\u003ecall for price\u003c\/td\u003e\n\u003ctd\u003eordered in\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003eSold in random lengths, cut to suit. The 86 × 19 mm board is ordered in; call for a price. 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, plus 10% for cuts.\u003c\/p\u003e\n\u003ch2\u003eWhat Grey Box decking is like\u003c\/h2\u003e\n\u003cp\u003eGrey Box, \u003cem\u003eEucalyptus moluccana\u003c\/em\u003e, grows from Jervis Bay in NSW up to the Atherton Tableland and is one of the hardest Australian decking timbers: WoodSolutions gives a seasoned hardness of 15 kN at about 1,105 kg\/m³, with durability Class 1 above ground and in the ground and a termite-resistant heartwood. The boards are pale yellowish-brown to light brown, plainer and more even than Spotted Gum, with a fine interlocked grain.\u003c\/p\u003e\n\u003cp\u003eThe sapwood is susceptible to lyctid borer, so decking is cut from heartwood. It moves less than Silvertop Ash and Blackbutt once seasoned, which helps a wide deck stay flat.\u003c\/p\u003e\n\u003ch2\u003eWhere it suits\u003c\/h2\u003e\n\u003cp\u003eChoose Grey Box where ironbark would do the job but you want a lighter colour: pool decks, commercial areas and decks that stay damp. Like ironbark it qualifies for BAL-12.5 and BAL-19 under the AS 3959 density rule but is not on the bushfire-resisting timber list, so it cannot be used for decking at BAL-29; for that, choose Spotted Gum, Blackbutt or Merbau.\u003c\/p\u003e\n\u003ch2\u003eFixing and finishing\u003c\/h2\u003e\n\u003cp\u003ePre-drill, two stainless or Class 3 galvanised screws per board per joist, 450 mm joist centres, 4–5 mm gaps on the 135 mm board. It takes oil slowly, so brush 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 what does not soak in. Screws and joist tape 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\/iron-bark-timber-decking\"\u003eGrey ironbark decking\u003c\/a\u003e – the other 15–16 kN board, darker in colour\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 Grey Box decking cost?\u003c\/h3\u003e\n\u003cp\u003eOn our website on 14 October 2026, 135 × 19 mm is $15.90 per lineal metre. The 86 × 19 mm board is ordered in; call for a price.\u003c\/p\u003e\n\u003ch3\u003eGrey Box or ironbark?\u003c\/h3\u003e\n\u003cp\u003eAlmost the same hardness and durability. Grey Box is paler and more even in colour; ironbark runs grey to chocolate with red boards. Neither can be used at BAL-29.\u003c\/p\u003e\n\u003ch3\u003eIs it termite resistant?\u003c\/h3\u003e\n\u003cp\u003eThe heartwood is, in the WoodSolutions and Queensland Government tables. Treat the subframe anyway if it is in contact with the ground.\u003c\/p\u003e\n\u003ch3\u003eDoes it bleed?\u003c\/h3\u003e\n\u003cp\u003eLess than Merbau and Blackbutt. Wash it down before the first oil as with any hardwood.\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":68913649549346,"sku":"GHT-9773","price":15.9,"currency_code":"AUD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0917\/3981\/5970\/files\/greybox-135-19-img.jpg?v=1792367798","url":"https:\/\/greenhilltimbers.com.au\/products\/greybox-timber-decking","provider":"Greenhill Timbers","version":"1.0","type":"link"}