Why Plywood Composite Construction is Better

Why Plywood Composite Construction is Better

Just like with cats, there are a lot of ways to skin an RV.  While they all have their pros and cons, some methods are better than others.

Bad

Plywood

By itself Plywood is cheap and easy to work with, but in the thicknesses required to be strong enough it is heavy and because it is susceptible to water damage it requires a lot of maintenance.  Without further treatment it won’t last long at all.

Laminates/Siding

Plywood is often used with another protective coating on top of it in order to make it more durable.  Historically aluminum siding was used.  It is currently popular to laminate thin sheets of fiberglass to thin sheets of plywood.  This combines the durability and water protection of fiberglass with the ease of handling of plywood sheets.  Both of these methods have one major flaw.  They both require joints between the different sheets of plywood or siding.  Even if very large sheets are used to reduce joints along the sides of your RV, there are still joints at the corners.  The edges and back of laminated plywood are still vulnerable.  In addition, it is sadly common for manufacturers to use cheap press board with water soluble glue as their plywood  backing.  Once the joints fail, which they will do, and water is introduced, disaster results.

Aluminum over plywood

Better

Aluminum

Aluminum is light, strong, and doesn’t require much maintenance but it is expensive and requires special tools and skills to construct and repair.  There is a reason most aluminum RVs ever produced are still on the road today.  There is also a reason they cost more than any other RV.

old airstream bambi

Fiberglass

Fiberglass is a popular choice for boats and for small RVs.  It has the important advantage of creating a seamless waterproof shell that is also very durable.  It requires a little more maintenance than Aluminum since it is vulnerable to UV radiation from the sun making regular re-finishing necessary.  For the large manufacturer, the ability to use molds to create copies makes mass production easy.  Unfortunately for the home builder or hobbyist, these molds are expensive and difficult to produce.  They are only cost effective if you plan on using it multiple times.

It may be surprising to many people, but fiberglass is also quite heavy.  Most shells require up to 7 layers of glass cloth and epoxy.  This is one reason it is popular for small RV trailers but isn’t used often in larger vehicles.

And finally, it has poor aesthetic properties.  Touch, feel, sound transmission, and a plastic look all contributed to fiberglass RVs  earning the nickname “plastic eggs”.

Fiberglass trailer

Best

The Stitch and Glue method creates a Plywood and Fiberglass Composite.  It has all of the advantages of fiberglass and fiberglass laminated skins while minimizing or eliminating the disadvantages.

  • The fiberglass exterior is waterproof.
  • Applying the fiberglass over the top of the finished plywood results in a shell with no seams.
  • High quality plywood with solid cores can be selected for strength and durability.
  • The plywood shell eliminates the need for expensive molds for the fiberglass.
  • The plywood is completely encased in epoxy virtually eliminating susceptibility to water damage.
  • Since only one layer of glass cloth is used over the plywood, and because plywood is lighter than fiberglass of the same strength, the shell is lighter than if built with fiberglass only construction.
  • Maintenance is minimal.  Many different coatings will work with the fiberglass exterior including polyurethane, latex house paint, two part professional paints, and automotive lacquers.
  • Like with aluminum, the shell results in a self supporting “pre-stressed” skin which eliminates the need for heavy framing further reducing weight.
  • Unlike with aluminum, no special skills or tools are needed for construction or repair.

Stitch and glue cross section

Our plans are all designed to be built with plywood composite construction.

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