What is co-extruded WPC?

The Basics

What is WPC?

WPC stands for wood-plastic composite. It blends reclaimed wood fibre with high-density polyethylene (HDPE) and a few binders, then extrudes the mix into fence boards. The wood fibre gives the board a natural, timber-like look and feel; the HDPE makes it stable and resistant to rot, insects and moisture. You get the warmth of timber without timber's habit of splitting, warping and rotting — and none of the ongoing oiling and staining.

That's the headline. But the composite core on its own still has a weak spot: an exposed composite surface can absorb water and fade in the sun. This is where co-extrusion changes everything.

What co-extrusion and the ASA/PE cap do

Co-extrusion means the board is made in a single pass with two layers fused together: the WPC core, and a tough outer shell called the cap. Fencly uses an ASA/PE cap that bonds to the core as the board is formed, creating a hard, UV-stable, moisture-proof outer skin. Because the cap is co-extruded rather than glued on afterwards, it can't peel or delaminate — it's genuinely part of the board.

The cap is where the performance lives. It carries the UV stabilisers that keep colour true, it seals the composite core against water, and it gives the surface its stain and scratch resistance. In short, the core provides strength and the timber character; the cap provides the longevity.

Capped vs uncapped composite

This is the distinction that decides how a composite fence ages — and where a lot of cheap "WPC" quietly cuts corners.

• Uncapped WPC has an exposed composite surface. It drinks up moisture, fades, stains easily and can swell — often visibly within three to five years. It looks fine on day one and tired soon after.
• Capped WPC seals that same core inside a protective ASA/PE shell. It holds its colour, shrugs off stains and stays dimensionally stable for far longer. It's the version that still looks right a decade later.

If a composite fence quote looks unusually cheap, uncapped board is often the reason. Fencly only supplies co-extruded, capped WPC. For a broader head-to-head with other materials, see WPC vs timber and WPC vs Colorbond.

Why it matters for warranty & longevity

The cap is what a manufacturer can actually stand behind. Because a co-extruded ASA/PE cap protects against UV fading, moisture and staining, Fencly backs its board with a 15-year written warranty — read the detail on our warranty page. Uncapped composite usually carries shorter or heavily caveated warranties, because its failure modes are predictable. For a fence you want to fit once and forget, capping isn't a nice-to-have; it's the whole point.

How Fencly's board is made

Every Fencly board is co-extruded with a wood-fibre-and-HDPE core wrapped in a bonded ASA/PE cap, in a woodgrain finish and a range of colours. It's the same capped board across our privacy fencing, gates and cladding, so the whole boundary ages together. Choose it once, install it (or let us), give it the occasional wash, and it holds its look for years.

Ready to explore? Browse the range on the WPC fencing Sydney hub, see the colours, check the cost guide, or read how to install a WPC fence and our installation service.