Ask The RV Engineer

The 7 Types of RV Subfloors

I certainly don’t know of every subfloor on the market. But I’ve used, seen or researched quite a few. I feel confident saying that 95% of the RVs in the country use one of the following types of subfloors. Most either use seamless OSB subflooring or an insulated, framed floor with 5/8″ tongue-and-groove decking.

Example of an RV framed subfloor from Jayco

TYPES OF RV SOLID FLOORS

Ol’ Standby: 4×8 Plywood Sheets

In ye olden times, RV floors were made from 4×8 sheets of plywood. This size of sheet – four feet wide, eight feet long – is the standard size for a construction sheet good in the U.S. construction industry. These sheets were commonly laid side by side – not end to end – along the length of an RV.

Many manufacturers still use 4×8 sheets to build RV floors. It’s time-consuming compared to a single jumbo-sized piece of flooring, but it’s a popular pick for stick n’ travel trailers with insulated subfloors (more on that later).

4 responses to “The 7 Types of RV Subfloors”

  1. Sal Marinosci

    There are composite boards used in construction that American plywood carry. Also asack a trim material comes in wide sessional boards. Also star board used for building bulkheads in boats. It can be done much better than they build them. Good marine plywood seals with resin can be waterproof.

    Reply
  2. Reader

    Great article, thank you!

    Reply
  3. tirod3

    The homebuilding supply industry isnt responding well to the more extreme conditions RVs are subjected. They also dont consistently describe products or accurately. I’ve done searches for waterproof subfloors, and both words are inaccurately used. Waterproof will get recommendations for plywood or osb, which experienced owners know isn’t, and subfloor, the structural part that holds us up between the joists, is conflated with underlayment, usually a thin film to help the subfloor become water resistant. Not proof. In home construction, concrete does that job, which isnt light. thin, or easily fastened down.

    Waterproof isnt an easy to find or cheap product, even in the marine industry. And like was said about waterproof osb, treated outdoor plywood falls apart just like the lesser priced stuff, it just takes longer. All it does is kick the can down the road further. Looking into poly decking hasn’t uncovered a light product or one priced as inexpensively as plywood. It seems the search continues. I’m not sure stainless sheeting will meet the need, either. However, if there is a way to build a washdown serviceable floor in an RV, I’m sure it can be done.

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  4. Rick Hoeksema

    Outstanding review, helps me immensely! Excellently written and very understandable and easy to follow article. You have more than answered all of my questions. Many thanks!!

    Reply

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