Merbau Decking 140×19 Long Length Random

Merbau decking, 140 × 19 mm in long random lengths from 4.2 m to 5.7 m: a kiln-dried, Select Grade imported hardwood with a smooth face and reeded reverse, Class 1 durable above ground, and on the AS 3959 bushfire-resisting timber list for decks up to BAL-29.

• Lengths: long random lengths from 4.2 m to 5.7 m, sold per lineal metre, for long runs with fewer end joins; also sold in 1.8 to 5.7 m random and set lengths random lengths from 1.8 m to 5.7 m, usually the better price per metre; also sold in set lengths
• Timber: Merbau (Intsia bijuga and I. palembanica), imported from Southeast Asia and the Pacific; orange-brown when cut, darkening with age; about 830–860 kg/m³, Janka hardness 8.5 kN
• Durability: Class 1 above ground, which the Queensland Government rates at more than 40 years’ expected life; the heartwood is termite resistant
• Bushfire: on the AS 3959 list of bushfire-resisting timbers, so it can be used for decking up to BAL-29 (BAL-40 and Flame Zone need tested systems)
• Joist spacing: 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°
• Gaps: 4–5 mm between boards at installation for 140 mm seasoned hardwood (WoodSolutions deck design guide)
• How much for a deck: with a 4.5 mm gap, each m² takes about 6.9 lineal metres, so a 20 m² deck needs about 140 lineal metres plus about 10% for offcuts, and roughly 31 fixings per m² on 450 mm joists
• Low decks: 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
• Fixing: two fixings per board at every joist, at least 12 mm from edges and ends. Pre-drill: WoodSolutions notes Merbau tends to split unless pre-bored. Use stainless steel within 1 km of the coast or 1 m of a pool. See our decking screws
• Reeded reverse: WoodSolutions says either face can go up. Reeds add grip across the board but hold moisture, so keep a reeded-up deck clean in damp spots
• Tannin: Merbau can bleed tannin and gum that stains concrete, paving and brickwork. Seal all faces and cut ends, and to oil new boards straight away, draw the tannin out first with Intergrain UltraPrep Tannin & Oil Remover
• Finishing: 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: CUTEK CD50, Intergrain Universal Timber Oil or Sceney’s Timber Decking Oil
• At Greenhill: stocked at 170 Settlement Road, Thomastown, with pickup or delivery across Melbourne and regional Victoria. Compare species on our hardwood decking page.