What you need to know about Merbau for decking

Due to its extreme durability, Merbau is commonly used for decking, flooring, staircases, boat building, and making outdoor furniture. Also known as Kwila, Pacific Kwila, Ipil, and Vesi, Merbau is grown in the South East Pacific rim, and is widely available in Australia.

Merbau is harvested from tropical forests in North Queensland, Malaysia, Fiji, Vietnam, the Philippines, Madagascar, Papua New Guinea, Thailand, Solomon Islands, New Caledonia, Vanuatu, Indonesia and Samoa. Trees can grow up to 40 metres high, with a trunk diameter of around 60cm.


When freshly cut, Merbau heartwood is a beautiful orange-brown colour, which reddens as it ages. This in sharp contrast with Merbau sapwood, which is usually white, buff or pale yellow in colour. Merbau has small gold or yellow flecks throughout the wood, which can help to differentiate it from similar species such as Kapur. Its grain is usually interlocked or wavy. Merbau has a density rating of 850kg per cubic metre, which is exceptionally dense even among hardwoods.


Merbau is a favourite choice for decking projects because of its excellent durability. With a durability class of 2, Merbau can be expected to last for 15 to 40 years without decay. The combination of its unusual density and strength make Merbau more durable than most other timber used to make outdoor decking and furniture. These attributes result in minimal shrinkage, resistance to rot and insect attacks, and great performance in extreme weather and even saltwater.


Merbau is also very versatile, and is relatively easy to work with using most carpentry tools. However, while the wood will cut cleanly, over time it may cause wear on the cutting edges of your tools. It finishes well with stain, polish and paint, but if there is a drawback to using merbau it’s the tendency that it has towards tannin bleed. Tannin is a polyphenolic compound that when leeching from Merbau causes it to stain whatever surface it runs onto. If you are using Merbau on or near a surface that will stain, we recommend that you either give the wood time to season elsewhere, or you wash it repeatedly with a deck clean product containing oxalic acid. This way the tannins will be able to run out of the timber and won’t cause staining in or near your home. The good news is that tannin only leeches from Merbau for a short time after it is harvested, so this is not a long term concern.

Common Uses

Apart from decking, Merbau is also commonly used to make furniture, bench tops, counter tops turned objects, musical instruments, and tool handles. It is used to make marine jetties and staircases, boats and flooring. It can also be used in large scale engineering and construction projects, and in infrastructure projects to create cross arms, piles, sleepers, posts, and in bridge building.


Working with Merbau comes with the same considerations that accompany all other timbers. To avoid irritation of the skin, nose and eyes, safety goggles, gloves and a face mask should be used when sawing and sanding Merbau. If you haven’t previously washed the timber with a deck cleaning product, Merbau should be left for a few weeks after being laid to season in the weather and lose the last remaining tannins.

Why choose Merbau?

So, why should you choose Merbau for your decking project?

• Weather resistance: Ideal for harsh and diverse climates.
• Durability: It will last as long as any hardwood on the market
• Strong: Merbau has a high density and great toughness rating.
• Appearance: It has a beautiful, rich colour and texture.
• Workability: Merbau is very easy to work with and has minimal shrinkage.
• Resistant: It resists rot and insect infestation.

What is a Vented Ridge?

A vented ridge is a customised form of ridge cap that allows for the extraction of warmer air from within a gable pergola.

The way that a vented ridge works is by allowing air to escape by raising the ridge cap on the pergola using a steel “z section” which has holes along its length. These holes allow air to move into and out of the structure. As they are sitting under the ridge cap and are angled inwards however they won’t allow rain into the pergola.

Vented Ridge

Vented Ridge

To install a vented ridge you will need to order the correct metalgoods for the task. You will need a vented ridge cap (differs from a standard ridge cap as it has 40mm overhangs on each side to prevent weather from entering) Two  Z section flashings, as well as two end caps.

You need to ensure that you have a 40-50mm gap between the ridge and the top purlin on either side of it so that the air can escape through the ridge. Attach your roof sheets only as far as the edge of the top purlin, to ensure that the gap between the purlin and ridge is not covered over and will allow the air to flow through.

Vented ridge cross section

Vented ridge cross section

Once your roof sheets are on, attach the Z section to the top purlin with polycarbonate screws (or whichever screws you’ve used for your roofing) Be sure to pre drill a 10mm hole in your roof sheets for each screw to allow for movement.

Once the Z section has been attached to your roof sheets, you can install the ridge. Using pop rivets, attach the ridge to the top of the z section. Once this is done, you simply have to put the end caps in place (with rivets) and your ridge is complete.

Vented ridges are available in a number of Colorbond® colours, to order yours, give us a call or send an email and we can deliver to your home!