If you've got grandkids running around barefoot after a swim, or an ageing parent who's less steady on their feet than they used to be, "is it slippery when wet" isn't a minor detail — it's often the deciding question before any decking material gets chosen. The honest answer for Merbau: fresh, smooth boards can get slippery when wet like any hardwood, but grip is something you can influence at almost every stage, from board profile to finish to where you add extra safety measures. Here's what actually affects it.
Merbau's Natural Grip vs Other Timbers
Merbau's grain is naturally more textured than some lighter, smoother hardwoods, which gives it a reasonable baseline grip compared with a lot of timber decking options straight off the stack. It's not the grippiest surface available underfoot, particularly on a fresh, sanded board, but it's also not unusually slippery for a hardwood — the differences between species matter less than what's done to the surface afterward, which is where the next two sections come in.
How Oil Finish Affects Slip Resistance
Oiling a Merbau deck deepens its colour and protects the timber, but a fresh coat of oil can leave the surface slightly slicker than an unoiled or weathered board while it's curing. A matte or low-sheen decking oil handles this better than a high-gloss finish, and the effect is temporary — grip typically improves within the first few weeks as the oil cures fully, and continues to improve as the timber weathers and develops surface texture over its first year or two.
Merbau Around Pools — What to Know
Pool surrounds carry the highest stakes for slip safety, and they're not left to guesswork — pool decking in Australia is governed by Australian Standards that set minimum slip-resistance ratings for wet areas, and Central Coast Council enforces them at inspection. Merbau boards machined with non-slip grooves go a long way toward meeting that standard while still giving you a natural hardwood look and rich colour against the water, rather than defaulting to a composite surface if timber is what you want around the pool.
Non-Slip Additives and Grooved Board Options
If grip is a particular concern — for a pool deck, a shaded area that stays damp, or simply peace of mind — there are a few practical options beyond just waiting for the timber to weather:
- Surface profiling or grooving. Machined grooves or a textured surface milled into the board increase grip without changing the timber's appearance dramatically.
- Non-slip coatings and additives. Clear anti-slip additives can be mixed into an oil finish, or a dedicated non-slip coating applied over the top, to boost grip without covering the timber's natural look.
- Non-slip strips or nosing. Targeted at high-risk spots like stair edges and step nosings, rather than the whole deck.
We can profile the surface or apply a non-slip treatment at installation, or retrofit it to an existing deck if grip has become a concern after the fact.
Making a Deck Safer for Kids and Grandparents
Slip resistance on the boards themselves is one part of a safer deck — the rest comes down to a few details that matter more for young kids and less steady adults than for anyone else. Secure, code-compliant handrails and balustrades along any edge or change of level are the single biggest safety factor, particularly on stairs. Non-slip nosing on step edges, good lighting for evening use, and keeping the deck clear of algae, moss and leaf litter — often the real cause of a "slippery" deck rather than the timber itself — round out a deck that's genuinely safer to use, not just compliant on paper.
Merbau isn't a slippery timber by default, and the grip factors above are all things we plan for at the design and installation stage, not afterthoughts. If safety underfoot is a priority for your household, tell us that upfront and we'll build it into the quote.