Hello everyone, I'm a long time lurker first time poster because I'm not able to find an answer for this particular question anywhere, please feel free to link to a thread, I'm not very good at using the search function. Anyways, here's my question: I'm building a 5x9 HF squaredrop so I'm extending out 6" over both sides and building wheel wells over the tires as well as bolting a 1x5 foot subframe to the front of the trailer to support the front overhang. My plan is to do a 1.5"XPS sandwhich with 1/8" baltic birch laminated to both sides and the cross memebers shimmed to provide support. Will the sandwich floor be strong enough with just a perimeter frame or does there need to be 2x2 spars running widthwise to strengthen the cantilever?
If Spars are necessary should they be directly over the crossmembers or in between so the foam can be supported by the metal crossmembers?
Will be towing with a prius, hence the 1/8" ply.