The case for composite caravans

COMMENT

For many years the caravan construction debate has raged between north and south: timber or aluminium wall framing?

It’s still unresolved, with each side claiming structural or climatic benefits, but it’s been superseded by another debate over old or new technology: framed or full composite construction?

The ‘framers’, who include big names like Concept, argue that it’s light, quick to build and repair in experienced hands, more adaptable to design changes and cheaper.

The ‘composite’ crowd, which has more advocates every year, starting with Jayco, say their construction is the future: thermally more efficient, quicker to build, rot proof and potentially cheaper with better resale.

Then there are ‘hybrids’, those like Roma who combine composite wall construction with fibreglass front and rear clips, or Trakmaster, who employ full composite walls with timber framed and fibreglass clad front and rear sections to give them the flexibility to custom-build in low volume to different widths.

Aluminium or fibreglass composite?

Then there’s the debate that still rages over whether it’s better to have aluminium or fibreglass outer cladding on composite walls.

Avan is the most vocal proponent of aluminium here, citing its resistance to age- yellowing over the years as a major benefit. However, big insurance companies like CIL have also got into the act, offering customers a 10 per cent policy discount if their van has fibreglass outer cladding. This is not so much an endorsement of fibreglass composite construction, but a recognition that fibreglass is generally more resistant to hail damage than conventional ribbed aluminium and therefore is less likely to need repair.

But some manufacturers lay fibreglass sheets over timber or aluminium-framed walls, so this doesn’t really contribute to the framed versus full composite wall debate.

The real issue for most RV manufacturers isn’t ethical or practical, but financial. Full composite panels are produced by a range of companies  in Australia or overseas, with some favouring those imported from Europe over local. Some cite quality, but it really comes down to price, which is governed largely by volume.

Jayco makes its own composite panels because, with around 44 per cent of the market, its volume makes that cost-effective; other major Australian makers don’t want to make that major investment in manufacturing machinery and buy panels in – probably at a higher unit cost.

OK, but who cares? If you are buying a new or second-hand caravan, what are the benefits to you?

Better insulation

There’s no question about it; full composite-walled caravans insulate you better from the elements than ‘stick and tin’ vans. The main reason here is that composite panels employ bonded ‘sandwich’ construction, which means that polyurethane is compressed and bonded under pressure between two slim panels, be they fibreglass or aluminium on the outside and fibreglass or ply on the inside.

In contrast, stick-and-tin framed wall vans have brittle polystyrene foam cut and placed between the frame uprights and horizontal noggins.  This material is not as good an insulator and the way it's fitted to the walls varies considerably among manufacturers.

Many manufacturers like Brisbane-based Apollo, that builds Winnebago caravans, are now also using one-piece composite panels for their roof, and/or floor. Whereas most composite wall panels are of 29mm or 30mm thickness, many floor panels are now of honeycomb construction up to 44mm thick and hence are used to stiffen the chassis at the expense of some weighty cross members.

Coromal is now using a one-piece 50mm thick composite panel for the roof of its latest off-road vans and impressively, like an increasing number of manufacturers, offers a five-year warranty on water ingress.

Composite roof panels are particularly popular in Europe, where many people use their caravans during winter as bases for alpine skiing or bush-walking.

Less chance of water ingress 

Without overlapping wall or roof joins, there's less opportunity for water to enter the caravan’s framing and set up the perfect conditions for rot, which is what ultimately claims most older caravans.

Ease of maintenance

I think it’s probably true that smooth aluminium cladding is less susceptible to yellowing over time, but an annual polish or even better, lifetime protection from new with a product like RVGard, overcomes this potential issue.

Better still, once polished or protected, fibreglass is easier to clean after a trip, as the dirt will not stick to it and can even be removed with a quality waterless wash and a microfibre cloth.

Easy to repair

People have been repairing fibreglass boats for decades and the technology is well known to all repairers. I rest my case.

Good resale

I often use the phrase ‘future-proofing’ when discussing what features you should order on your new caravan.

You mightn’t intend to take it far off the bitumen, but independent trailing arm suspension will make your caravan easier to sell, because the next owner might want to.

Dual batteries and roof-mounted solar panels might not be much use to you if you only stay on powered sites in caravan parks, but the next owners night prefer to free-camp.

A separate shower and toilet might not be important to you, but it probably will be to the next owner.

Composite wall construction is the future, with more and more makers, like JB, Coromal, Avida, ZoneRV, AusRV, Winnebago and Nova, etc, going down that path while ‘stick and tin’ is the past.

Draw your own conclusion.