Our Professional Merbau Construction Process
Building with Merbau isn’t like throwing up a pine deck. This timber demands respect and proper technique, otherwise you end up with problems that shouldn’t exist. Timber Selection and Preparation We handpick every Merbau board that goes into your deck. Sounds excessive, but hardwood varies – some pieces have more character, some have tighter grain. We sort through to match boards appropriately and check for any defects that might cause issues later. Then comes acclimatisation. Merbau needs time to adjust to Central Coast conditions before installation. We store timber on-site for at least a week, letting it stabilise to local humidity and temperature. Skip this step and you’ll get movement after installation. We learned that lesson the hard way years ago. The Pre-Drilling Requirement Every single fastener hole gets pre-drilled. No exceptions. Try to drive a screw straight into Merbau and you’ll either snap the screw or split the timber. We use specific drill bits sized for the fasteners, and we drill pilot holes even for the substructure connections. Takes longer, costs more in labour, but it’s the only way to do it properly. Stainless Steel Everything Here’s something that catches people out – you cannot use galvanised fasteners with Merbau. The tannins react with galvanising and create ugly black staining that won’t come out. We use 316 marine-grade stainless steel for all fixings. More expensive? Yes. Worth it to avoid permanent stains on your beautiful hardwood? Absolutely. Spacing and Expansion Merbau moves less than softer timbers, but it still moves. We leave appropriate gaps between boards – usually 4-5mm – for expansion and drainage. In our humid coastal environment, this spacing prevents boards pushing against each other during wet periods. Substructure Engineering Supporting heavy hardwood requires serious substructure. We typically use hardwood or treated pine joists at closer spacing than you’d use for lighter decking. The framework needs to handle the weight without flexing, and we seal all cut ends with quality sealer to prevent moisture wicking into exposed end grain.

Finishing and Maintaining Your Merbau Deck
Getting a Merbau deck built is one thing. Keeping it looking good for decades is another. The good news? It’s not complicated, but there’s a bit of attention needed in that first year. Initial Oil Application We recommend oiling Merbau decks shortly after installation – usually within the first month. This enhances that rich colour and provides extra protection while the timber’s settling in. We use penetrating hardwood oils designed specifically for dense timbers like Merbau. The oil soaks into the surface rather than sitting on top like varnish. The Tannin Leaching Phase Remember those natural tannins we mentioned? First wet season, they’re coming out. You’ll see brown streaks on the deck surface and potentially staining on anything below – paths, walls, whatever’s underneath. This is temporary. Most of the tannin leaches out within 6-12 months, then it stops. During this phase, we tell clients to hose the deck down after rain. Rinses away the tannin residue before it dries and helps the process along. Don’t stress about it – every Merbau deck goes through this. Long-Term Maintenance Schedule After that first year settles down, Merbau becomes pretty low-maintenance. A good sweep and occasional wash keeps it clean. Every 12-18 months, depending on exposure, an oil treatment maintains the colour and provides ongoing protection. If you prefer the natural silvered look, you can literally do nothing. Merbau will grey off beautifully and still perform structurally for decades. Some of our clients love that weathered appearance – saves them the oiling maintenance. Recommended Products We typically suggest penetrating oils like Cutek or Intergrain. These products work well with Merbau’s density and our coastal conditions. Avoid film-forming coatings – they’ll peel and look terrible on hardwood. Coastal Environment Care Salt air actually doesn’t hurt Merbau much, but regular rinsing helps. A decent wash every few months removes salt buildup and keeps the timber breathing properly. In our Central Coast location, this basic care goes a long way.
Merbau Performance in Central Coast Conditions
We’ve built decks across the Central Coast for years now, and Merbau consistently proves itself in our specific environment. The salt air that eats through so many materials? Merbau handles it without issues. That natural density and oil content creates a barrier that coastal conditions can’t penetrate. We’ve got Merbau decks in Terrigal, right near the water, that are 15 years old and still structurally perfect. Humidity doesn’t faze it either. Central Coast gets humid – properly humid during summer – and plenty of timber species struggle with that moisture. Merbau’s stability means minimal cupping, twisting, or warping even through our wettest periods. The UV exposure we get here is intense. Summer sun beats down on decks relentlessly. While Merbau will darken and eventually silver without treatment, it doesn’t degrade structurally from sun exposure like softer timbers can. The hardness protects it. What really sets Merbau apart for coastal properties is longevity. You’re not replacing boards every five years. You’re not dealing with rot or decay from our moisture levels. Install it properly with appropriate fixings and substructure, and you’re looking at decades of performance. For Central Coast homeowners investing in outdoor living spaces, Merbau delivers that perfect combination – beautiful appearance, genuine durability, and proven performance in exactly our conditions.

Frequently Asked Questions About Merbau Decking
Properly installed and maintained, you’re looking at 30-40 years, sometimes longer. We’ve seen Merbau decks from the 80s still going strong. The Class 1 durability rating isn’t marketing talk – this timber genuinely lasts.
No. The brown streaks from tannin leaching wash away once the process finishes. They might temporarily stain concrete or render underneath, but these clean up. We recommend hosing down surrounding areas during the first wet season to prevent buildup.
Definitely not. Galvanised or zinc-coated fasteners react with Merbau’s tannins and create permanent black staining. You need stainless steel – preferably 316 marine grade. It costs more, but there’s no alternative if you want your deck looking right.
Less than most people expect. After the first year’s tannin phase, an oil treatment every 12-18 months keeps the colour rich. Or leave it untreated and let it silver naturally – still performs perfectly, just looks different. Either way, it’s minimal work compared to softwood decking.
Fresh Merbau has reasonable grip, but like any smooth hardwood, it gets slippery when wet. We can profile the surface or apply non-slip treatments if this concerns you. Most clients find it manageable, especially once the timber weathers a bit and develops some texture.
Honestly, it varies based on site access, design complexity, and current timber pricing. Merbau sits in the premium range but below exotic imports. We provide detailed quotes after assessing your specific project – no point guessing numbers that might be completely wrong for your situation.
Ready to Build Your Merbau Deck?
We’ve been constructing Merbau decks across the Central Coast long enough to know what works and what doesn’t. Every project gets the same attention – proper timber selection, correct installation techniques, and the quality fixings that Merbau demands. If you’re considering Merbau for your outdoor space, let’s talk about your specific property. We’ll come out, assess your site, discuss design options, and provide a detailed quote that covers everything. No surprises, no hidden costs. We also keep Merbau samples at our workshop. Seeing and feeling the timber in person makes a real difference – photos don’t capture that rich colour and grain properly. You’re welcome to drop by and check out the quality before making any decisions. Contact us today for your free Merbau deck consultation and quote. Phone: 0240036404 Email: info@deckingcentralcoast.com.au Servicing: Terrigal, Avoca Beach, Copacabana, and surrounding Central Coast areas We’ll get back to you within 24 hours with available times for a site visit. Let’s build you a deck that’ll still look fantastic in 30 years.