Choosing the proper decking lumber is the most important decision you can make when building a deck. It will shape the outdoor lifestyle of your home. Because of Australia’s severe UV rays and changing humidity, choosing a material based only on pricing might cause it to bend, decay, and need expensive repairs in just a few years. If you like the rich, natural look of hardwood or the low-maintenance promise of modern options, it’s important to know how different species do in your area. We’ll go over all you need to know in this guide to make sure your pick lasts and adds value to your property.
The Type of Wood You Choose: Hardwood or Softwood
When it comes to decking, the most typical question homeowners have is whether to choose hardwood or a treated softwood like pine. Most of the time, this choice boils down to how long it lasts against how much it costs up front.
Hardwoods: Trees that grow slowly, such Spotted Gum, Merbau, and Ironbark, make these woods. They are thicker, hard to scratch, and can persist for 25 to 40 years or more.
Radiata Pine is a softwood that has been chemically treated to keep pests and rot at bay. It is the cheapest decking wood, but it is easy to damage and usually only lasts 10 to 15 years.
Hardwood decking lumber is usually always the best choice for long-term investments in family spaces with a lot of foot traffic.
Finding the Best Decking Timber: Top Species
You will probably find a few regular winners when you look for the best decking wood. People all around the world love merbau decking wood because it lasts a long time and has a beautiful reddish-brown colour. This wood is naturally resistant to decay, hence it is a Class 1 durability wood. But keep in mind that Merbau can “bleed” tannins when it first gets wet, which can leave stains on nearby pavers.
Spotted Gum is a high-quality decking wood that is popular for its bright grain and low shrinkage. If you want a local look, this is a great choice. It is also naturally fire-resistant, which is why it is so common in homes in areas prone to bushfires in Australia.
How long will your deck really last?
The “Durability Class” of the wood determines how long it will last.
Class 1 (Ironbark, Merbau): 40 years or more above ground.
Class 2 (Spotted Gum, Blackbutt): 15 to 40 years.
Class 4 (Treated Pine): 5 to 15 years.
Things like direct contact with the soil or bad ventilation can cut these estimates down by a lot. A deck that is cleaned and oiled every year will endure at least ten years longer than one that isn’t.
The Grey Look: Style vs. Care
Many modern building styles use grey decking wood because it seems like it’s been battered by the sea. There are two ways to do this. First, you can pick a high-quality decking wood and let it weather on its own for 6 to 12 months. The sun’s UV rays will fade the natural colours, creating a silver patina.
If you want the beauty without the structural deterioration of untreated wood, you can also use a specific tint. Using a good oil on grey decking wood keeps the wood flexible and free of cracks, and it keeps that ash-toned tint. Even the greatest decking wood will eventually ‘check’ (have cracks on the surface) if it doesn’t get oil.
The Big Debate: Timber vs. Composite
Is wood or composite better? Merbau decking wood is the most beautiful natural wood and stays cooler underfoot throughout a hot Australian summer. Composite, on the other hand, is almost “set and forget.” The feel of wood is the best for a weekend DIY project. Composite might be the way to go if you desire a life with no upkeep, even though it costs more up front.
Technical Setup to Keep Warping from Happening
The best way to keep your hardwood decking boards from warping or “cupping” is to give them plenty of air. There needs to be at least 300mm of space under the framework so the boards can breathe. Always leave a space of 4mm to 6mm between boards so they can expand. If the bottom of the board stays wet while the top dries in the sun, the board will bend.
Choosing the Final Budget
How much does it cost? In Australia, you should expect to pay:
Treated pine costs between $200 and $350 per square metre to install.
The cost of installing merbau decking wood is between $450 and $600 per square metre.
For premium decking wood like Spotted Gum or Ironbark, it costs $600 to $800 per square metre to install.
Keep in mind that the boards are only roughly 30% of the total cost of the project. Don’t cut corners on the sub-frame or the stainless steel fasteners. Choose a traditional merbau decking timber or a local hardwood decking timber, but make sure to pick one with a good durability rating so that your investment lasts.
FAQs
1. Do I need permission from the council to build a wooden deck?
You don’t require a permit for a “low-level” deck (usually less than 600mm high and less than 25$m^2$) in many parts of Australia as long as it doesn’t compromise drainage or the safety of the structure. But the restrictions are very different in different jurisdictions (like NSW and VIC) and even in different local councils. A building permit is nearly always required if your deck is high up, close to a property line or in an area that is prone to bushfires. Before you start building, always check with your local government or a professional certifier to avoid big fines or having to take down the building.
2. How can I pick the correct “Hazard Class” (H-Rating) for my deck?
When you buy the sub-frame (the structure underlying), you’ll notice ratings like H3 or H4. This shows how much chemical treatment the wood has had to keep it from rotting and getting termites:
H3: Made to be used “Above Ground.” This is great for the decking boards and the joists that aren’t touching the ground.
H4: Made for usage “in the ground.” You need to use H4 or higher for any posts that are buried in dirt or concrete.
If you use H3 wood that touches the ground, it will break down in just a few years.
3. Why are red stains “bleeding” on my tiles from my new deck?
This happens when tannins leach out of the wood, which is a natural process that happens when oils that dissolve in water wash out. Most of the time, it happens with Merbau and some Eucalypts. The red-brown run-off can create stains that are hard to get rid of if your deck is close to light-colored pavers or a pool. You can “bleed” the wood yourself by hosing it down and washing it with a deck cleanser many times before sealing it. Alternatively, you can buy “pre-leached” or “pre-sealed” boards from your provider.
4. Is it possible to install a wooden deck right on top of concrete?
Yes, but you can’t put the boards right on the concrete. To make an air gap, you need to put in a “sleeper” system or low-profile joists. The gap should be at least 50mm wide, but more is better. If there is no airflow, moisture will get stuck between the wood and the concrete, which will cause it to rot, mould, and warp quickly. Also, make sure the concrete has a modest slope so that water doesn’t collect under your joists.
5. How can you keep wood planks from breaking?
When the wood dries up and the fibres pull apart, it commonly splits or “furs.” Regular oiling is the greatest way to keep things from happening. A good decking oil gets into the fibres and keeps them flexible and moist. You will need to sand the surface back to smooth wood before putting on a new layer of oil if your deck is already splintering. If you want to avoid splinters in high-traffic places where people walk barefoot, like around a pool, choose a high-density hardwood like Spotted Gum instead of a softer wood like Pine.
The timeless beauty of Merbau Decking is frequently the first step in turning your backyard into a high-end outdoor retreat. This hardwood is a must-have for outdoor living in Australia because of its deep, wine-red colours and legendary durability. However, keeping it in top shape needs more than just an occasional hose-down. Proper care is what makes the difference between a weathered surface and a lifelong investment. This includes regulating the first “bleed” of tannins and keeping the wood safe from the intense sun in the Southern Hemisphere. Taking care of your Merbau Decking properly can keep your entertainment room the focus of your house for many years to come, whether you’re putting in a new one or fixing up an old favourite.
Where does the wood for Merbau come from?
A lot of people who care about the environment want to know: Where does merbau timber come from? This tough hardwood comes from the Indo-Pacific region, which includes sections of Southeast Asia, Papua New Guinea, and the Pacific Islands.
The wood has adapted to endure a lot of wetness and humidity because it grows in tropical rainforests. But because it is so popular, it is important to get your resources from trusted providers like Austimber, which focuses on sustainably harvested timber. You can be sure that your Merbau Decking fulfils Australian regulations for moisture content and structural integrity by choosing high-quality providers like Austimber. This lowers the chance of warping or cupping after installation.
The Pre-Maintenance Phase: Dealing with Tannin Bleed
“Tannin bleed” is the most well-known (or infamous) thing about a new merbau timber deck. Merbau has a lot of water-soluble tannins in it. When the wood gets wet for the first time, whether from rain or a hose, it lets off a dark, tea-colored liquid.
If you don’t take care of this liquid, it might leave permanent stains on light-colored concrete, pavers, or pool copings. Many experts say that the best way to deal with this is to “pre-weather” the deck by hosing it down every day for a few weeks or using a specific tannin stripper. During this first step, suppliers like Austimber often tell clients to put down plastic drop sheets on their site to catch any runoff. Your Merbau Decking is ready to be cleaned and sealed once the tannins have been removed.
Step-by-Step: How to Clean Your Merbau Deck
Cleaning merbau timberdecking is not the same for everyone. It needs a mix of chemical action and physical movement.
Get ready: Begin by taking out all the pots and furniture. To clean the Merbau Decking surface, use a stiff broom to sweep away debris and leaves.
Using chemicals: Use a special wood cleaner that has oxalic acid in it. This acid is needed to “brighten” the wood and get rid of any tannins that are still there.
The Scrub: Use a stiff-bristled brush made of plastic to scrub the cleaner into the wood. Concentrate on locations that get a lot of foot traffic and where dirt builds up the most.
The Rinse: Get rid of the chemical with a yard hose. Be thorough; chemicals left on the wood can make it harder for the final oil coating to stick.
Expert FAQ: The Seven Most Important Questions Answered
We put together a list of the most common questions that Australian homeowners have about their Merbau Decking to assist you learn how to take care of it.
1. How can I keep Merbau tannins from leaving stains on my concrete?
You need to either pre-weather the wood or apply a tannin remover right after installation to stop reddish-brown tannin “bleed.” If your deck is already bleeding, spraying it with water often will help it heal faster. Use a temporary plastic drop sheet or a special concrete sealant to protect the concrete around it. If you have stains, use a solution of oxalic acid or a store-bought deck cleaner to get rid of them. Before putting any oil on Merbau, it’s recommended to let it sit outside for 4 to 6 weeks or use a “power prep” chemical cleaner to lock in the tannins.
2. How do you clean a Merbau deck before putting oil on it?
To start, sweep the deck to get rid of any loose dirt. While the wood is still wet, use a special deck cleaner that usually has oxalic acid in it. Use a stiff-bristled synthetic brush to scrub the surface. Don’t use wire brushes because they can hurt the wood fibres. Wait 10 to 20 minutes for the solution to rest, making sure it doesn’t dry up. Then, use a garden hose to rinse it off well. This process opens the grain, gets rid of grey “dead” wood cells, and neutralises any tannins that are still there. This makes sure that the new oil can get deep into the Merbau Decking.
3. Is it okay to use a power washer on Merbau decking?
Yes, but you need to be very careful. Even though merbau is a hardwood, strong pressure can still “fur” the wood, which can cause splinters and permanent scars. Set the pressure low and use a broad fan nozzle. Keep the wand at least 30 cm away from the surface. Always go with the grain. Don’t ever use a “turbo” or revolving nozzle since they are extremely rough on wood. For the best results, only use a pressure washer to rinse off chemical cleansers. Don’t rely on the water pressure to get rid of dirt or stains.
4. What is the best cleaner for Merbau decks in Australia?
Oxalic acid-based cleansers, such as Cabot’s Deck Clean or Intergrain UltraPrep, are the best for most Australian decks. They do a good job of “brightening” the wood by getting rid of grey aged lignin and tannin stains. If your deck is very dirty and has old, peeling oil on it, you might need to use a sodium hydroxide-based stripper to get rid of the old coating first. If you want to clean your own home, a mixture of Napisan (sodium percarbonate) can work, but professional-grade acidic cleaners make the surface more even and neutral.
5. How do I get rid of the grey weathering on antique Merbau?
When the wood is exposed to UV light, it breaks down the cells on the surface, which makes it look grey. You need a chemical repair to get the original deep red colour back. Use a wood brightener that has oxalic acid in it. This chemical reacts with the greyed fibres and iron stains to “bleach” the wood back to its natural colour. Put the cleanser on a wet deck, scrub it hard, and then rinse it off. If the wood is very weathered or feels fuzzy, you will need to lightly sand it with 80-grit sandpaper once it has dried to show fresh wood before you re-oil it.
6. Should I sand Merbau before I clean and oil it?
Not all the time. A chemical clean is generally enough to get the surface ready if the deck is fairly fresh or in good shape. But you should sand if the wood is splitting, has significant scratches, or has a thick, peeling old layer that cleaners can’t get rid of. Cleaning alone doesn’t open the pores of hardwood as well as sanding with 80-grit paper does, which lets the oil sink in more deeply. A mild sanding is usually a good idea to get the smoothest finish and the longest life out of your oil.
7. Where can I get oxalic acid to clean my deck?
Major hardware stores like Bunnings or Mitre 10 are the best places to buy oxalic acid in Australia. “Deck Clean” is the most popular name for it when it is sold as a pre-mixed liquid. You may also get it as a concentrated powder, which is cheaper for big areas because you can mix it with water yourself. Always wear gloves and eye protection when you work with these chemicals because they can be moderately corrosive.
Final Steps: Oiling vs. Staining
The last step is to safeguard your merbau timber deck once it has been cleaned and dried. You usually have two options for your Merbau decking: coatings that are water-based or oil-based.
Oil-Based: These give a classic look and soak deep into the wood. They are great for keeping the wood flexible and stopping it from cracking.
Water-Based: These sit more on the surface and usually protect against UV rays better, which is very important in Australia’s harsh climate.
When you put on the finish, make sure to work in the direction of the grain and do one board at a time to eliminate lap marks. If you got your wood from an expert like Austimber, ask them what kind of coating they recommend. The amount of moisture in the wood when it is installed can affect which treatment works best.
A merbau timber deck is a beautiful addition to any home. It adds warmth, lasts a long time, and gives the property a sense of elegance. You can better comprehend what is merbau timber and how to take care of it if you know where it comes from. If you’re dealing with initial tannin bleed or recovering an old surface, the most important thing is to be consistent.
Your merbau timber decking will look great for years to come if you have the correct tools, put in some hard work, and choose high-quality materials from professionals like Austimber.
A Merbau deck is a stunning and durable addition to any Australian home, prized for its rich, warm colouring and natural resilience. Known in Southeast Asia as Kwila, Merbau (Intsia bijuga) is an exotic hardwood that stands up beautifully to our unique climate, from intense sun to heavy rains. Its high-density, interlocking grain provides a stable and strong surface perfect for outdoor living.
However, even the most durable timber requires care to retain its aesthetic appeal and structural integrity over time. The key to a long-lasting Merbau deck lies in consistent and correct maintenance. This includes everything from routine cleaning to tackling common issues like tannin bleed and ensuring the right protective oils are used. By understanding how to properly care for your deck, you can prevent common problems and keep your investment looking its best for decades to come.
Understanding Merbau’s Unique Characteristics
Before you start any maintenance, it’s important to understand what makes Merbau unique. Its defining feature is a high concentration of natural oils and tannins. These oils are part of what gives the timber its remarkable durability and resistance to pests and rot. The merbau timber suppliers you choose can often provide more detail on the specific variety, but all share these core characteristics. The merbau timber itself is a beautiful, dark reddish-brown, which can turn a silvery-grey over time if left untreated.
The most significant maintenance challenge unique to Merbau is tannin bleed. When the timber is exposed to moisture, its natural tannins can leach out, resulting in a dark, reddish-brown stain on surrounding surfaces like concrete, tiles, or paving. This is most prominent in the first few weeks after installation but can recur with heavy rainfall. Taking proactive steps to manage this is crucial for a clean, attractive outdoor area.
Step-by-Step Guide to Cleaning Your Merbau Deck
Regular cleaning is the most important part of your deck’s maintenance routine. For a merbau timberdecking surface to remain vibrant and healthy, it needs to be free of dirt, mould, and grime.
Start by sweeping the deck thoroughly to remove all loose leaves, dirt, and debris. This prevents the debris from becoming a muddy paste when wet. You can then use a timber cleaning product specifically designed for hardwoods, or a simple solution of mild detergent and water. Avoid using harsh chemical cleaners, as these can strip the timber of its natural oils and protective finish.
Apply the cleaning solution with a stiff-bristle brush, working it into the timber in the direction of the grain. This helps lift embedded dirt without damaging the surface. Once scrubbed, rinse the entire deck thoroughly with a garden hose. A pressure washer can be used with extreme caution, but it’s essential to use a low-pressure setting and a fan spray nozzle. High pressure can splinter the timber fibres and cause irreversible damage. Ensure all soap residue is completely rinsed off to prepare the surface for oiling.
Preventing and Treating Merbau Tannin Bleed
Tannin bleed is a natural process and a tell-tale sign of the Merbau timber’s rich composition. To minimise the impact on your property, there are a few effective strategies.
The most common method is a thorough pre-washing of the timber before installation. This involves laying the timber out and hosing it down with water, allowing the tannins to bleed out onto a non-staining surface. This process may need to be repeated over several days until the water runs clear. After the pre-wash, allow the timber to dry completely before installation.
If you have already installed your deck and notice tannin stains on concrete or masonry, a dedicated tannin remover product is the best solution. These products are designed to neutralise and lift the stains without damaging the surface below. Always test a small, inconspicuous area first to ensure it doesn’t cause discolouration.
Oiling: The Secret to a Beautiful and Protected Finish
Oiling your Merbau deck is not just about aesthetics; it’s a critical step in preserving the timber’s integrity. The natural oils and colour of the timber will fade over time due to sun and rain exposure. Applying a quality decking oil helps to replenish these oils, protect the surface from UV damage, and maintain the rich, dark colour.
For Australian conditions, choose a high-quality, oil-based decking oil with a good UV protectant. These products are specifically formulated to penetrate the dense fibres of Merbau, providing a deep, nourishing treatment. The frequency of oiling depends on your deck’s exposure to the elements. Decks in full sun may need oiling every six months, while those in shaded areas might only require it annually. A good indicator is when the timber starts to look dry and a little faded.
Before oiling, ensure the deck is completely clean and dry. Apply the oil with a lambswool applicator, brush, or roller, working in thin, even coats and following the timber grain. This ensures the oil is absorbed properly, preventing a sticky, patchy finish. Avoid over-application, as this can lead to pooling and an uneven look.
Other Maintenance Tips for Your Merbau Deck
Beyond cleaning and oiling, here are a few more tips to keep your deck in pristine condition.
Watch for Moisture: Merbau is water-resistant, but standing water can still cause issues. Ensure there is good ventilation beneath the deck and that water drains away effectively. Avoid leaving wet pots or other items on the surface for extended periods, as they can cause moisture spots and mould.
Regular Inspections: Periodically inspect your deck for any signs of wear, splintering, or loose boards. Addressing small issues quickly can prevent them from becoming major problems.
The Versatility of Merbau: While this article focuses on decking, remember that Merbau is also a popular choice for Merbau timber flooring and other joinery applications. The same principles of cleaning and oiling apply to these indoor applications, though the frequency will be much lower due to the reduced exposure to the elements.
By following these maintenance steps, you can ensure your Merbau deck continues to be a beautiful and functional part of your home for many years. Its classic look and enduring strength make it a smart choice, and with the right care, it will only become more beautiful with age.
Creating your dream space is about more than just choosing the right furniture and décor—it’s also about selecting the perfect materials to bring your vision to life. With Austimber’s exquisite selection of Merbau and Blackbutt timber, you can elevate your space with the timeless beauty and natural warmth of these stunning wood varieties.
Unparalleled Beauty and Durability
Merbau timber is renowned for its rich, reddish-brown hue and distinct grain patterns, making it a popular choice for both indoor and outdoor applications. Its natural resistance to decay and termite attacks also ensures that your investment will stand the test of time, even in harsh environmental conditions. On the other hand, Blackbutt timber boasts a lighter color palette with creamy tones and subtle variations, offering a contemporary yet classic aesthetic that complements a wide range of design styles.
Versatile Applications
Whether you’re designing a cozy interior retreat or creating an inviting outdoor oasis, Merbau and Blackbutt timber are incredibly versatile materials that can be used in a variety of ways. From stunning hardwood floors and elegant staircases to stylish decking and durable fencing, the possibilities are endless when it comes to incorporating these beautiful timbers into your space. Their natural beauty and durability make them an ideal choice for both residential and commercial projects alike.
Sustainable and Eco-Friendly
At Austimber, we are committed to sustainable forestry practices and environmental stewardship. That’s why all of our Merbau and Blackbutt timber products are sourced from responsibly managed forests, ensuring that future generations can continue to enjoy the beauty of these magnificent trees. By choosing Austimber for your timber needs, you can feel confident knowing that you’re making a sustainable and eco-friendly choice for your home or project.
With Austimber, you’re not just purchasing timber—you’re gaining access to our team of experts who are dedicated to helping you bring your vision to life. Whether you’re a seasoned builder or a DIY enthusiast, our knowledgeable staff are here to provide you with personalized guidance and support every step of the way. From selecting the right timber for your project to offering advice on installation and maintenance, we’re committed to ensuring your satisfaction from start to finish.
Experience the Austimber Difference Today
When you choose Austimber for your timber needs, you can trust that you’re partnering with a company that is dedicated to your success. Let us help you turn your vision into reality contact us today to learn more about our products and services and discover how we can assist you with your next project.
Contact Austimber today to speak with one of our experts and start bringing your vision to life. Whether you’re a professional builder or a DIY enthusiast, we’re here to provide you with the guidance and support you need to achieve exceptional results.
