Anyone have floor problems in ultralight trailer?

GrandpaKip wrote:

WoodGlue wrote:
When you're talking about mushy floors, I'd be willing to bet that 99% of those floors affected are using OSB! OSB and Luaun are a set-up for a failing floor.

WoodGlue

I'll take that bet, any amount. Considering how long OSB has been around, my guess would be that the vast majority of floor problems in RVs have occurred to a plywood floor. And still do today. I couldn't begin to count how many plywood roofs, floors, and walls I've repaired due to rot. Way more than OSB. Water is the most destructive force on Earth. There isn't much of any common material that handle being continually wet without losing structural ability.

PS Lauan is a plywood and, when used to its design parameters, is every bit as good as anything else in the same application.

Agreed. People are very misinformed concerning OSB because its very convenient to group it into one large category.
OSB comes in a lot of different variations, initially there were problems with the 1st generations of OSB however Advantech and other OSB products are superior in many ways.

Lauan plywood is not a bad product either however it is often misused.
It is inexpensive and easy to work with however it is not the cure all universal product that uninformed installers try to make it out to be.

It's all about using the correct product for the application.

WoodGlue wrote:
When you're talking about mushy floors, I'd be willing to bet that 99% of those floors affected are using OSB! OSB and Luaun are a set-up for a failing floor.

WoodGlue

I'll take that bet, any amount. Considering how long OSB has been around, my guess would be that the vast majority of floor problems in RVs have occurred to a plywood floor. And still do today. I couldn't begin to count how many plywood roofs, floors, and walls I've repaired due to rot. Way more than OSB. Water is the most destructive force on Earth. There isn't much of any common material that handle being continually wet without losing structural ability.

PS Lauan is a plywood and, when used to its design parameters, is every bit as good as anything else in the same application.

myredracer wrote:
One thing about overall floor and frame construction I don't like is with all the enclosed under-bellies these days, you have absolutely no idea how well things were designed or how good the workmanship is. I'd love to see what the joists, frame and everything else looks like under our TT or ones on a dealer's lot, but I can't.

It's great for the manufacturers because they can hide all kinds of problems under the coroplast. They can call the construction heavy duty or whatever they want, but what does it really look like? And if it's related to the frame in any way, they just direct you to the frame manufacturer to duke it out with.

I was at one RV show last year and I was jumping (lightly) on the floor in one TT with a BAL/Norco Ultra-frame to see how solid it felt (I'm not a heavy person either at well under 200 lbs). Some guy came in who I'm pretty sure was a dealer or factory rep. and he freaked out and said don't do that or you can go through the floor. Maybe he knows something the rest of us don't. Not very re-assuring if that's all it takes to go through a TT floor.

That issue about the underbelly access is easily and for a moderate cost fixable ... take a look at what I did CLICKY

Larry

WoodGlue wrote:
When you're talking about mushy floors, I'd be willing to bet that 99% of those floors affected are using OSB! OSB and Luaun are a set-up for a failing floor.

WoodGlue

What?

So you're saying that every floor that is made with OSB is bound to fail or that every OSB floor that gets some water on it is going to fail? And you're condemning Lauan plywood with it, also?

Is this because Lance trailers have a plywood floor and everything else is forbidden?

WoodGlue wrote:
When you're talking about mushy floors, I'd be willing to bet that 99% of those floors affected are using OSB! OSB and Luaun are a set-up for a failing floor.

WoodGlue

What evidence do you have to back up that sweeping indictment?

myredracer wrote:
One thing about overall floor and frame construction I don't like is with all the enclosed under-bellies these days, you have absolutely no idea how well things were designed or how good the workmanship is. I'd love to see what the joists, frame and everything else looks like under our TT or ones on a dealer's lot, but I can't.

It's great for the manufacturers because they can hide all kinds of problems under the coroplast. They can call the construction heavy duty or whatever they want, but what does it really look like? And if it's related to the frame in any way, they just direct you to the frame manufacturer to duke it out with.

I was at one RV show last year and I was jumping (lightly) on the floor in one TT with a BAL/Norco Ultra-frame to see how solid it felt (I'm not a heavy person either at well under 200 lbs). Some guy came in who I'm pretty sure was a dealer or factory rep. and he freaked out and said don't do that or you can go through the floor. Maybe he knows something the rest of us don't. Not very re-assuring if that's all it takes to go through a TT floor.

Your the exception. 99.5% of buyers will never look underneath a trailer before purchase.

When you're talking about mushy floors, I'd be willing to bet that 99% of those floors affected are using OSB! OSB and Luaun are a set-up for a failing floor.

WoodGlue

One thing about overall floor and frame construction I don't like is with all the enclosed under-bellies these days, you have absolutely no idea how well things were designed or how good the workmanship is. I'd love to see what the joists, frame and everything else looks like under our TT or ones on a dealer's lot, but I can't.

It's great for the manufacturers because they can hide all kinds of problems under the coroplast. They can call the construction heavy duty or whatever they want, but what does it really look like? And if it's related to the frame in any way, they just direct you to the frame manufacturer to duke it out with.

I was at one RV show last year and I was jumping (lightly) on the floor in one TT with a BAL/Norco Ultra-frame to see how solid it felt (I'm not a heavy person either at well under 200 lbs). Some guy came in who I'm pretty sure was a dealer or factory rep. and he freaked out and said don't do that or you can go through the floor. Maybe he knows something the rest of us don't. Not very re-assuring if that's all it takes to go through a TT floor.

myredracer wrote:
I know one downside to OSB is in a horizontal application, it doesn't do well if it gets wet for too long. I have to wonder if a spongy floor sometimes could be due to a water leak. Personally, I hate OSB. It's heavy, it smells awful and it gives you awful slivers. I assume the smell is formaldehyde off-gassing.

I wonder what spans they typically use for floor joists in TTs? If they are using 24" centers, by building code standards I just looked up, the OSB would have to be 23/32" or 3/4" thick T&G. For 16" centers, it should be 5/8". Do they ever use 16" centers? I really have to wonder if OSB that use sometimes is just too thin for the joist spacing? I sure can't see them using 3/4" OSB in a TT esp. if they call it an ultra-lite.

Are you sure OSB is rated for a higher load? It's been a while since I've been involved with the building code aspects but this is from a plywood manufacturer: Plywood is a highly stable panel. When exposed to moisture or high humidity,plywood is up to seven times more resistant to thickness swell than substitute wood-based (OSB) panels. Plywood also returns to its original dimensions when it dries. Plywood is stronger than substitute wood-based panels in the four important engineering strength properties of bending, tension, compression and planar shear and plywood weighs up to 40% less than substitute wood-based panels of equivalent thickness. Plywood is a highly impact-resistant panel and continues to perform even when wet. I wonder if different grades of plywood are used in different regions of the US & Canada? We get a lot of rain around here and I know it's the choice of structural engineers (at least in BC).

Our house is 100% plywood because I designed & built it myself. :) OSB is really common on spec houses and townhouses but rainscreen assemblies are now required on exterior walls which is something that came out of the leaky condo crisis of the 80s.

westend wrote:

myredracer wrote:
Some sub-floors are OSB and some are plywood. I would expect more potential trouble with OSB. Our TT has plywood which is one of the reasons we bought it. I wouldn't buy one with OSB.

I'm not really sure what exactly defines "ultra-lite". I think it's more of a marketing ploy to suck people into thinking their TV can handle the weight.

It's not always about a single material subfloor. Some mfgs. use a composite structure of luan or cheap plywood and foam. Although this type of sandwich construction has a lot of strength along it's shear face axis, it is hard to get real strength through the composite core axis. I would venture that the "spongy floor" complaints happen in high traffic areas, around the entry or in front of the sink cabinet.

FWIW, if your S&B house or apartment was built in the last 20 years, you'll probably find OSB is under your feet. OSB is rated at higher load and water resistance than interior plywood. Mostly true for roof sheathing, as well but depends on geography for that.

I have my own feelings about OSB vs plywood, especially by the application. The fact is that these sheathing products are rated to their use, not all plywood or OSB being the same. Given the same dimension and rating, OSB has a slight edge, mostly because of the void-free nature vs plywood.

In our trailers, you can bet that the mfg's engineers have spec'd the floor sheathing to meet the ragged edge of capacity (in most cases). There have been a few posts on this forum and others about failures of a composite floor. Once the bond between foam and sheathing loosens or the foam parts, internally, there is nothing to keep the structural integrity of the floor. Additionally, it is miserable to repair whereas a single subfloor sheet can be cut out and replaced without the hardship that the composite panel presents.

IMO, there is no place for foam in a floor being a part of the structural, load bearing capacity. If it was as good as the engineers proclaim it to be, everyone that owns scaffold plank would be replacing their aluminum plank with composite panels, tomorrow.

I placed 1/2" plywood over the high traffic areas in my new Rockwood a few years ago and traded it off when it was two years old. I did not like that "sinking feeling" after a few months of use.