Check Before You Buy: Main Frames & Flooring

When you first step on the lot and look at all your options, it's easy to get carried away looking at the superficial things. Having the prettiest finishes and upholstery is nice, but you want the vehicle to last years and trips to come, which means the most important thing is the build quality. It's not easy to see, but the structure of your next RV determines whether you'll be driving it for a few years or a few decades.

Main Frame

The frame is the RVs skeleton, and like ours, it determines the health of the whole vehicle. Many times manufacturers will skimp on quality in the frame and invest in pretty features that ultimately don't matter. When the TV breaks you get a new one, but when your frame starts to fail, a cascade of expensive repairs are headed your way.

When looking at trailers on the lot, an important factor in structural strength is the spacing of cross members in the main frame. Look for cross members that are no farther apart than 4' on center. Having fewer cross members will allow for more flex and warping in the frame, leading to windows and doors coming out of square and causing expensive repairs. It can be difficult to check cross members when most RVs are wrapped in aluminum skirting. Ask for all the information you can get on the structure of the RV you are looking at. You can also examine the bottom of the slide-out to see the cross beam spacing.

The main frame is the starting point for overall frame quality. What's built on top of it counts too, of course. We will be covering stick-built vs. aluminum and fiberglass built units in an upcoming post so stay tuned for more.

Flooring

The interior structure of the build is also very important if you want a long and happy life for your RV. Water damage is one of the most common problems in RVs. Choose a strong floor that holds up well to water, minimizing damage from any leaks. Of course, you need to maintain the exterior of your RV so as to minimize leaks, but if something should happen, you want to know your RV has a floor that will hold up.

At Jim's, all of our trailers are built on 5/8" marine-grade tongue in groove plywood decking. Wherever you shop for your trailer, make sure the floors are not constructed of OSB decking, which swells up much easier than plywood when exposed to water, and quickly breaks down under repeated exposure to water.

Here's a quick tutorial on the differences between OSB and plywood:

OSB stands for "Oriented Strand Board." It is constructed of wood chips and strips glued together under high pressure with resins. It costs less than plywood because it's made of scrap material, but it's not as strong as plywood because the wood doesn't have an intact grain. OSB will damage and swell up much easier than plywood when repeatedly exposed to water.

Plywood is made of thin layers or "plies" of wood veneer that are glued together with the grain oriented in a different direction on each layer. There are many grades of ply. The ideal floor for an RV is marine grade, where the layers of ply are bonded together with a waterproof resin that makes for a highly water resistant product.

On the issue of floor quality, we'll leave this last word to this happy Jayco owner who summed it all up with a comment on an RV chat board:

"My previous travel trailer had OSB floor that literally melted when wet. I had a leak by the door and when I took up the linoleum you could scoop up the remains of the OSB with your hands. I'll take plywood over that cheap stuff any day."