Reread my post. The other construction that Haulmark uses in their motorhomes and toterhomes is an aluminum framed vacuum bonded wall. Haulmark does not use any welded steel in their walls or roof.

As far as the strength of FRP that is what Renegade uses in their trailers, motorhomes and toterhomes. So you might see what their comments are about using FRP.

The reason why Haulmark switched from their aluminum framing was strength in the stacker trailers. That was what I was told. Perhaps the reason they decided to use FRP is the proximity of their factory to Renegade's. They are on opposite sides of I-80. You can see the other company's building from either parking lot.