Foamie overlap question

[TallScott]

When the 6 inch overlap on the edges of the roof get glued down question. What should the condition of the walls below it be? The walls are canvas that is TB to foam and otherwise raw. Should the wall be left raw or painted before gluing on the 6 in overlap? They will get painted after in the standard 50% first coat etc. Thanks, Scott

[zzzizxz]

I am building my first foam camper, so I don't know from personal experience either way. That being said, I've seen a few people saying that it really doesn't matter, whether there is canvas and paint/TB in the joint before you glue it. It all gets covered and waterproofed with canvas and paint anyway, and you may get better adhesion if there is canvas in the joint.

[GPW]

Are you guys using a “reinforcing" Strip of canvas below the overlap ? … as suggested ...

[TallScott]

Guess I missed that suggestion. I don't recognize the term. Would you kindly point me and the right direction for or explain?

[GPW]

Scott it’s merely another strip of canvas underneath the skin to further reinforce Foam Joins … I’ll make you a drawing in the morning or you can browse my gallery … I use them all the time …

[RJ Howell]

Scott it’s merely another strip of canvas underneath the skin to further reinforce Foam Joins … I’ll make you a drawing in the morning or you can browse my gallery … I use them all the time …

Believe I saw you draw this for the inside for another's build. Is it required inside and outside? I'm hoping to only do this on the inside (as I see done with wood boats).

[GPW]

RJ, this was originally done to provide extra skin strength on the corners … a decision we never regretted ...

[RJ Howell]

RJ, this was originally done to provide extra skin strength on the corners … a decision we never regretted ...

The main question was: Is it required inside and outside? I get that it's re-inforcement. Just is it required on both sides? With fiberglass boat building you do it to the inside only, so it does not have a seam that needs to be sanded out on the outside. Would doing a smaller strip, then a larger strip to the interior do the the same as interior and exterior?

I'm asking because I'm reaching this point and have never worked with foam before!

[GPW]

RJ, Maybe , maybe not …. That was all a leftover from when we came here and proposed the idea of a foamie trailer , and people became quite irate . They said it would just Blow Up or Implode on the highway … So we did everything we knew to add extra strength to known stress areas. Is it necessary ??? I use it !!! Inside and out on the Foamie #1 , and just outside on the FoamStream …
I personally think if your construction is careful then maybe not … you decide how it looks to you !!!

Ps. my intention was to build a trailer that would last living Outside all the time , in the Sun and Rain …The FoamStream uses very heavy 18oz. canvas , and with a reinforcing strip , that makes it twice as Thick , or the equivalent of a piece of Leather… Very hard to cut or dent and very strong … all for the minor inconvenience of adding an extra piece first … It’s all how strong you want to make it .. If I’ve read correctly, larger and smaller piece on the inside and outside would not hurt … Places where we believe the greatest stresses are. where the walls meet the floor .
And then check out what others have done , some use it, some don’t … All Your choice .

Ps. if say an offroad trailer , then I’d say Yes , and more … Overbuilding for Strength with a Foanie is guilt free , the foam is so light compared to other materials …a little extra strengthening can’t add that much weight …

[Pmullen503]

You want the fibers of the canvas to go across the joints where stress will concentrate. If you can cover with a continuous piece of canvas, that's best. If you can't then strips that bridge and connect the two pieces of canvas are used.

Adding an extra layer of canvas for dent resistance is another matter. The canvas covering functions under tension, so as continuous a layer as possible should be your goal.

[RJ Howell]

Thank you to both of you for the responses. I re-enforcing inside and out, can't see why not to do so. Heck I'm even doing the window cut-outs.. again, can't see why not.

I'm going to ask another if I may.. I'm doing the inside with the bedsheets. Really wanted to see this whole coating thing before going for canvas. Will re-enforcing the outside with bedsheet be good? Then canvas over.

[Pmullen503]

I covered the inside of my foamy with linen. I should have used canvas as the inside gets more where and tear (I carry lots of gear in it.) By reinforcing, do you mean covering the joints first, then canvas, then another canvas strip over that?

My advice would be to be cover the sides, then top overlapping the sides at least 4 inches. Do them all the same day and saturate the overlap with TB.

[GPW]

JMHO, I don’t think you can do too much reinforcing … You can do too little and that will eventually show … Our first Foamie #1 had thin Linen on the outside and bedsheets inside … we doubled some bedsheet strips ( 8” wide”) along the floor to wall join and roof seams and plain fiberglass boat tape over the outside seams … ( see my photo gallery ~ page 24 ) and that lasted for many years till we sold it to Bonnie , who had a devil of a time cutting the cabin off the plywood floor …It even survived a serious Hail stormn here , looked like a Golf ball … two weeks in the sun and you couldn’t tell … It’s probably still somewhere … That was the Proof I needed ...

[RJ Howell]

I covered the inside of my foamy with linen. I should have used canvas as the inside gets more where and tear (I carry lots of gear in it.) By reinforcing, do you mean covering the joints first, then canvas, then another canvas strip over that?

My advice would be to be cover the sides, then top overlapping the sides at least 4 inches. Do them all the same day and saturate the overlap with TB.

I'm doing all seams, corners, joints, basically anywhere too pieces are connected. Doing it all first, then I'll cover the flats. Really didn't even think of doing it again over everything..