Caravan construction: Stick and tin vs composite panels

ByWes WhitworthMay 1, 2020
4 MINUTE READ
Caravan construction: Stick and tin vs composite panels

We hear these terms used often, but what do they mean for you? We examine the tried and tested old-school stick and tin versus the new-class composite panels

Have caravan manufacturing techniques and technology changed a lot over the past few decades? Not until relatively recently, and certainly not in all cases. With the old ‘stick and tin’ style cladding-over-frame construction method making way for the use of composite panels glued together, we thought it high time we looked at the differences. So what does each style entail?

Old Skool 4

Stick and tin

Stick and tin, as it’s known colloquially, was the most common way of building vans over the decades; close enough to nearly a century. For most of us, thinking about what a van looks like under the skin, you’ll most likely imagine a timber (often meranti) frame, with various types of panelling to the inside, and tin or aluminium cladding over the top, the outside. The frame is held together with glue and screws, with the cladding held down essentially the same way or with rivets.

Where this approach shines, is in the chassis under the van because that is where the strength lies. Often full box section, with the A-frame and chassis all but over-engineered. This construction method allowed the top (body) to move and flex a touch, and that was that; one caravan that would last the ages.

Old Skool 2

One of the greatest drawbacks to the stick and tin design is that they are prone to leak water; especially after decades of movement and slight gaps forming between the sheeting. This leaking leads to water damage of the timber and, in turn, frame rot. The flipside of this design is the weight in the chassis – it is built to handle just about any road, track, or trail we drag them along, but they’re incredibly heavy; especially when stood next to their newer counterparts.

Coromal Panels

Composite

Then around the early 2000s, we began to see a rapid increase in the number of vans that were built on a composite design. The entire body is often made from composite ‘sandwich panel’. The composite panel is often around 20-40mm thick and will have a fibreglass outer layer, polystyrene middle (think ‘expander foam’), and a thin inner layer made from aluminium or fibreglass again to sandwich it on the inside.

Avida's Roof Wall Section

Besides the lightweight properties of the composite materials, it’s also incredible at insulating the inside of the van from the ambient temperature outside. The frame of the stick and tin style van is gone, with the walls and roof being held together with a polymer glue and bracketing. The simplest way of thinking about a composite van wall, is to imagine a stick and tin wall, with the outer cladding, middle insulation, and inner walls, with framing throughout. Remove the frame, and the standalone insulation, squash and glue the inner and outer together (with polystyrene in the middle), and now you have the entire wall of the van in one piece. Adding windows is simple, as you just cut the window frame out of the side, and glue it in; no frames or timber to worry about.

In Production At Zone Rv

It’s all very rigid, and so doesn’t need a chassis that’s as strong, rigid, or heavy as a stick and tin alternative. A lot of the van’s strength is derived from the composite body, and so a lighter c-section chassis will often suffice.

A huge positive of composite sandwich panelling, there are no seams or joins as seen in stick and tin vans (apart from the roof corners/edges to the side panels). This means there are fewer places where the van can leak. If a leak does happen to occur, it can be resealed easily with a bit of silicone. The water that’s found its way in will dry out rather quickly, instead of being sucked into a timber frame, and beginning to rot. Indeed, in a stick and tin van, you’ll often only see water ingress after the timber has become completely saturated, and started rotting; whereas with a composite body, there’s nowhere for the water to be absorbed; so you’ll notice it straight away. And as you may know, where you see the water damage could be at the other end of the caravan from where the leak originated!

Large Cnc Machine At Avida

Pros and cons of each style

Stick and tin

Pros:

  • Easy to repair if the timber or aluminium gets damaged but more costly to replace an entire panel
  • Easy to add fixings/fasteners to the body – find a frame/stud and away you go
  • Can easily be modified/fixed by the owner
  • Heavy-duty chassis
  • Often utilise aluminium frames over timber

Cons:

  • Prone to leaks
  • Wood rot
  • Heavier chassis

Avida's Production Line End

Composite

Pros:

  • Lighter when combined with chassis
  • Less prone to leaking due to one-piece construction of walls and roof
  • No timber to absorb water and rot
  • Especially easy to repair with fibreglass
  • Cheaper to repair damage; though hard to do at home unless you have fibreglass knowledge
  • Much stronger than super light-grade alloy-over-frame designs

Cons:

  • Not available from all manufacturers if you’re brand focused
  • A touch more expensive to purchase

Coromal Strength

Conclusion

As you see, there are pros and cons to each manufacturing process, which is why the caravan industry hasn’t entirely embraced the composite approach and the tried and tested stick and tin remains popular; despite the lure of ‘space-age technologies’ in your caravan! Even so, good-quality vans still emerge from both manufacturing processes.

One of the major challenges an RV-maker needs to overcome when looking to change manufacturing technique is the different tooling, machinery, and knowledge and experience of its staff and the different trades they’re qualified in.

At the end of the day, it appears that a composite body is the way technology is going; yet, the stick and tin design is still functional at doing what it needs to do.

Let us know your thoughts and your experiences with either. (Unless you’re renovating an old caravan, we don’t do mental health counselling.)