What , precisely , do we mean when we say ‘ one-piece ’? Effectively , this refers to the fact that both side walls have no joins . They are a single panel spanning the length of the body of the van . The roof , meanwhile , is usually also a single panel , stretching from the drawbar to the very rear of the van .
Different manufacturers use different techniques to ‘ lock ’ these panels together , but ultimately there are fewer joins involved , which means the chances of the van springing a leak are greatly reduced .
During construction , when it comes to fitting things like windows and air-con units , the manufacturer will simply cut the correct shape out of the sandwich panel and secure the window or appliance without having to deal with framing , and seal it accordingly .
If a leak does occur , it should be much easier to repair because , in most cases , all you ’ ll need is a bead of silicone . Also , any water that does make its way inside can be dried out instead of being absorbed into any timber components and causing rot .
Sandwich panels get their name from the use of layers ( hence the term ‘ sandwich ’).
Done right , they are relatively light while offering high mechanical strength and load-bearing structural properties . The lighter weight enables greater fuel efficiency , thereby reducing operating costs . This combination of lightweight construction and the excellent insulation makes sandwich panels an ideal choice for constructing truck bodies , semitrailers , caravans and motorhomes .
Like a sandwich that you ’ d make for lunch , sandwich panels consist of two facings and a core . They are fabricated by attaching two thin , strong , stiff ‘ skins ’ ( either fibreglass or aluminium ) to a lightweight and relatively thick core between them .
The core usually consists of a lightweight foam , which provides the necessary structural integrity for the panel as well as insulation properties .