STYROFOAM Brand HIGHLOAD 100 Insulation

[dsm811]

Does anyone know if the 2" highload 100psi insulation could be used with glue and keyed (big dovetail?) joints at the top and sides and omit the wooded spars?

Maybe a foam cabinet/closet bulkhead at the front (glued and keyed) and the galley bulkhead at the rear (glued and keyed).

[GPW]

Dovetailing foam probably isn’t any stronger than just glued foam ... and Lots more work ... But if you want to do it that way ...that’s cool !!!

[atahoekid]

Omitting the spars may be a decision that changes depending on the width of your roof. My roof is 7' wide and laying the 2" foam across (not actually glued in place) and the foam sags a bit. I'll be putting some spars in. Nothing heavy duty, just enough to keep the foam from sagging in the center. If your roof needs to support loads, you may want to consider heavier duty spars

Just my thoughts...

[GPW]

Just a thought on spars ... wooden spars are fine and well proven ... but across a wide roof , even those may sag over time ...
Resorting to a structural support that won’t sag and has worked for thousands of years , we must mention “the Archâ€

[angib]

Go easy on benefit of the arch, because you have to get all the details right for an arch to be strong. For example, it relies on lateral restraint of the two ends for its strength, so a gentle arch between two sidewalls is no stronger than a straight spar. Only if the ends of the arch sit directly on the floor is it strong.

[dsm811]

I was hoping the Arch would solve all my problems.

How much wood min. for mounting other stuff like hinges, latches, lights , fan...?

[GPW]

Since we’re not building Cathedrals, I think the simple Arch will serve our Foamie Trailer purposes just fine ...

Use just enough wood to do the job and nothing more .... it’s the Foamie way .... Our Motto : "Wood Rots, Foam persists " ...