Aluminium Composite Panels vs Full Composite Construction: What’s the Difference (and Why It Matters in a Caravan)

Fibreglass composite with XPS core offers a one piece design with no joins giving the caravan less chance to leak

When you're investing in a high-quality off-road caravan, one of the most overlooked — yet most important — factors is how it's built. Not just the layout or inclusions, but the actual construction materials and methods.

Two common options in modern caravan builds are:

• Aluminium Composite Panels (ACP)

• Full Composite Panel Construction

They sound similar, but they perform very differently — especially when it comes to strength, durability, insulation, and condensation control.

Let’s break it down.

What Are Aluminium Composite Panels (ACP)?

ACP panels are made of two thin layers of aluminium bonded to a polyethylene or foam core. These panels are often used in cladding and caravan wall construction due to their lightweight properties and clean appearance.

✅ Lightweight ✅ Cost-effective ✅ Smooth, modern finish ✅ Easy to cut and shape

But ACP isn’t without its drawbacks…

The Downsides of ACP in Caravans

1. Thermal Bridging & Condensation

Aluminium is a highly conductive metal, which means it transfers heat and cold quickly. In cold conditions, the inside of the ACP can become colder than the air inside your caravan, creating moisture and condensation — especially around windows and corners.

This leads to:

• Damp internal surfaces

• Mold risks

• Long-term damage to cabinetry and linings

2. Structural Weakness

ACP panels rely on external framing (often timber or Aluminium studs) for strength. The panels themselves offer minimal structural integrity, which can lead to flexing, creaking, and eventual fatigue — especially on corrugated or offroad tracks.

3. Delamination Risks

Over time, especially in hot or humid environments, the bond between the Aluminium and core can weaken — a process called delamination. This can cause the panel to bow, bubble, or lose rigidity.

Offroad Grit RV Construction using Fibreglass Composite Panels with an XPS core

What Is Full Composite Construction?

Full composite panels (like those used in Offroad Grit vans) are single-piece structural panels, usually made of:

• A fibreglass outer skin

• An XPS foam or high-density core

• No timber, no external frame

These panels form the walls, roof, and floor of the van — bonded together for strength and thermal efficiency.

✅ Strong and rigid ✅ Excellent insulation ✅ No timber = no rot ✅ Fully sealed = less dust ✅ Much better at preventing condensation

Why Composite Wins for Offroad & Off-Grid Use

Thermal performance: XPS foam cores provide consistent insulation. No cold metal surfaces inside = no sweating walls or hidden damp.

Water resistance: No timber, no cavities, no capillary action. These panels are built for humid, coastal, and outback climates alike.

Durability: Bonded composite walls form a monocoque-like shell — no flex, no squeaks, and much better resistance to rough tracks or movement.

Weight efficiency: Despite their strength, composite panels are often lighter than ACP + frame systems, depending on design.

So Which Should You Choose?

If you’re buying a caravan to tow occasionally on sealed roads, ACP might be "good enough" — especially if budget is the priority.

But if you're serious about:

• Travelling off-road

• Living off-grid

• Reducing maintenance

• Keeping your van comfortable year-round

…then full composite construction is the way to go.

Final Thoughts

At Offroad Grit, we’ve chosen timber-free, full composite construction for every van we build — including fibreglass-infused flooring, XPS-core walls and roof, and durable PVC cabinetry.

Why? Because in the places our customers go, there’s no room for failure.

📩Want to learn more about how our construction sets us apart? Get in touch today