Big Queensland dealer embraces aluminium caravan framing

Queensland's Sunrise Caravans is in the process of switching its flagship range, which represent about one third of its sales, from Meranti timber to aluminium frame construction.

But rather than re-igniting the long-standing interstate debate on which framing material is better, the move is more pragmatic than technical, says Sunrise boss Steve Andonovski.

Andonovski established his dealership 10 years ago and recently moved into three-times larger premises nearby in Burpengary, north of Brisbane.

“As all of our caravan brands – Blue Sky, Montana, Sunset and Great Ocean – are built by separate Melbourne manufacturers, it’s not surprising that they all have had Meranti timber framing that has been the standard in the Victorian caravan industry for some time,” he said.

“But this has put us at a disadvantage if a local customer is adamant they want aluminium framing because of its perceived anti-rot benefits in tropical areas. So when we asked our flagship Sunrise manufacturer to switch over to aluminium framing and now we have all bases covered.”

All new Sunrise caravans are now being built with rivetted aluminium framing, which allows some body compliance to overcome potential stress fractures in prolonged Outback use for fully TIG-welded aluminium-framed caravans.

The new Sunruise 16ft 10in triple-bunk family off-road van with a transverse queen bed and a full internal ensuite that Andonovski will take to next month’s Let’s Go Queensland Caravan & Camping Supershow is the first of the new aluminium-framed vans.

The debate on which caravan framing material is superior is decades old and to some extent is based on interstate rivalry.

Not that long ago, the full composite fibreglass interlocking caravan body was the latest thing, offering a strong, simple, well-insulated - and with a lighter chassis this design affords - ultimately a lighter RV design.

It was hail-resistant and strong, with established off-road custom builders like Melbourne’s Trakmaster embracing it for its then-new Pilbara range.

Queensland manufacturers were particularly staunch in their support of aluminium framing, which first appeared locally in the 1970s with the likes of Viscount and Millard adopting the construction method instead of traditional timber frame.

Millard still uses aluminium frames today, but so do a growing number of other manufacturers, including Australia’s most popular caravan brand Jayco (albeit with a composite skin), but also the likes of Sunland and Bushtracker.

The main argument in favour of aluminium is that it's light, strong and doesn’t rot after water leaks.

The aluminium used in the Sunrise caravans is pop-rivetted C-channel to offer some compliance combined with strength.

But as aluminium is more expensive as a raw material than timber, it takes more of an investment by the caravan manufacturer to set up, as it needs more factory room to make and prepare the large frames. Thus the aluminium-framed Sunrise vans will cost more to produce.

The theory behind the use of aluminium is that the frame is protected over time against rot from water leaks, but countering that, it’s a fact of life that like any metal, aluminium will suffer from metal fatigue, with welded or riveted joints potentially cracking and loosening if given a hard time. This can be the case with vans of around five to 10 years old and more and the compromised structure is then much more likely to allow leaks.

Just because an aluminium frame can’t rot like timber, doesn’t mean the wood around the aluminium won’t. If ply is used in an aluminium-frame van (for inner walls, for example), that could rot if water gets to it. Some vans also use timber for shaped sections that again will rot if there’s water ingress. Even so, at least the van’s core body structure is not affected.

Meranti timber advocates argue that extensively metal-fatigued aluminium frames are much harder to fix than a small amount of timber rot. Moreover, a well-built timber van that has some ‘give’ can make for a good off-road van for that reason -- it doesn’t transfer road shocks as easily, absorbing them instead.

Because caravan manufacturers don’t all apply the exact same construction methods it’s hard to generalise and say that aluminium is the best body frame to have.

Yet you can see why the popularity of aluminium for framing isn’t waning. For the buyer who wants a rot-resistant, lighter and more rigid caravan than available with timber, aluminium is an enticing option.

Related: Are aluminium caravan frames better?