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Discussion Starter #103
I found it useful to have channels in the polyiso for things such as cabling. I mention it as it's at the right stage in the build for you and it would be hard to do it later.
Appreciate the heads up on that. I do have my electric plan ready, and it will not require any cabling thru / under the floor. With the exception of 2/0 cable bringing start battery current back to the DC charger, which I plan to run down the left side, under the driver seat and inside the path the triangle pieces cover like KoV and puffcard recommend here. (Probably has an official sounding name). My Renogy DC charger requires only 6 AWG cable, but I am planning 2/0 cable, as my original setup included a Battery Isolation Manager in lieu of the DC charger, using 2/0 cable with the ability to self jump if your starter battery morts. I may preserve that option with a Blue Sea battery switch, hence might as well use the heavier cable since I already have it.

Basic layout is the electric stuff is mostly on the driver side, a few wires into the ceiling for lighting and fans, and thru the ceiling for solar panels and cameras. The wet wall (fresh water, gray water, sink) is by the slider on the passenger side, so some wires DO have to cross over for the pump, kitchen AC outlets, etc. Since I have a fixed platform bed, there exists a pretty straight path to do so, shorter than running across the ceiling and with the advantage of being accessible for repairs and additions.
 

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Discussion Starter #104
Just leave an ⅛" space between the floor and the B pillar trim you will be able to slide it in and out fine. Mine is 1 ¾" think and I have no problem removing the trim piece.
I trimmed that lower trim piece to sit on top of my floor. It cuts easily with a jigsaw.
Thanks to all for the ideas. Looking at both, I personally would worry that little gap would collect gunk in time, and leaving an open gap near the door is an easy path for water to get under the floor. I like the idea of running the floor further and trimming the plastic piece and let it sit on top of the floor, probably easier to do than match the curve precisely, and with the added benefit of concealing my expected hatchet job with the flooring in those corners anyway.
 

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Thanks to all for the ideas. Looking at both, I personally would worry that little gap would collect gunk in time, and leaving an open gap near the door is an easy path for water to get under the floor. I like the idea of running the floor further and trimming the plastic piece and let it sit on top of the floor, probably easier to do than match the curve precisely, and with the added benefit of concealing my expected hatchet job with the flooring in those corners anyway.
I had to read thru these posts to understand the issue😳

Then I realize why - I’m lacking that plastic pillar base trim (my off the lot van came with a factory metal cab wall that I removed).

My 3/4” BB plywood floor started with a 5’ x 10’ which aligned flush with the metal edge of the van floor @ the slider & “scribed” to the raised metal cab floor @ the front. I left a small gap so the plywood would not rub & I was just going to caulk that gap (have not done that yet)

Either way; a small 1/8” caulking will “semi” seal off those surfaces.

The water issue is why I used XPS board in the floor rather than Polyiso (If Polyiso absorbs water the characteristics change & can breakdown - may not be probable, but definitely possible). Polyiso is the right stuff in the walls & ceiling, but I used XPS high load in the floor.
 

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31 August 2020. A little over 5 months from order date, "She-Who-Needs-A-Name" arrives at home. Interestingly enough, she spent 2 of those months in transit. $45,355 window sticker, $40K even out the door (including tax, tags, and dealer fees). A little over $8,500 in incentives and rebates.

First impressions...
(1) my feet hang well off the floor when the seat is fully swiveled. Will have to build up some floor storage in that area.
(2) the windshield wiper stalk is exactly where the shift lever is in my last van. So, wipers and washers engaged instead of transmission when I attempted to leave the dealership looking cool.
(3) everything else is exactly what I was expecting, and I am extremely happy with the RV prep package. Ride is nice when empty.

Seriously, in need of a name. CLFFRD was my last big red truck, still in the family, so can't re-use that one. Open to ideas here,,,

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Enjoyed the humour reading your post.. "Wipers/Washers on when leaving dealership @ looking cool "..... :)
 
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Discussion Starter #108 (Edited)
Two quick things accomplished today... (1) Put on the "Look Up, Dummy" decal next to the rear view mirror. Having previously driven (or attempted to) a rack full of expensive bicycles into my not-quite-tall-enough garage, I need one of these to remind me not to try THAT again. Use them on my other cars, they are vinyl clings so can be removed when not needed. But since, even without the rack, this will never fit in my regular garage, I think I will leave it there permanently. Not sure about the rear-view mirror, though. Since I have no windows out the back, I may remove the mirror and replace it with a small video monitor hooked to the rear camera.

(2) Sketched out a basic schematic for my kitchen plumbing. Simple, everything fits in one cabinet next to the slider. Options to add an electric water heater and/or shower head at the back or side door. Access to fill and dump tanks when door is open. Questions - do most folks put a dump line in the fresh water tank, and a blow-out port in the supply line, for winterizing? Or just rely on the pump?

edit - removed problematic plumbing schematic. updated one added at post #134

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Discussion Starter #109 (Edited)
my off the lot van came with a factory metal cab wall that I removed
The you didn't have to deal with the styrofoam "helmets" up on the ceiling? Does FMVSS 201 even apply in Canada? Or did you add them back in for the occasional jaunt across the border?
 

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Discussion Starter #110 (Edited)
The water issue is why I used XPS board in the floor rather than Polyiso (If Polyiso absorbs water the characteristics change & can breakdown - may not be probable, but definitely possible). Polyiso is the right stuff in the walls & ceiling, but I used XPS high load in the floor.
Not too late to change my mind. Indecision IS the key to flexibility. Pros and Cons, anyone?
 

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XPS seems to be the general best practice for floor insulation according to the internet in general. The guy at home depot also seemed 100% sure it would be much better. His opinion was that polyiso degrades under load and XPS doesn't. Also XPS Doesn't absorb much moisture which some argue is better for the floor where water is more likely to collect.
 

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XPS seems to be the general best practice for floor insulation according to the internet in general. The guy at home depot also seemed 100% sure it would be much better. His opinion was that polyiso degrades under load and XPS doesn't. Also XPS Doesn't absorb much moisture which some argue is better for the floor where water is more likely to collect.
Careful here; Where the HD guy is technically correct the real answer is it depends;

It depends upon what XPS board you buy. HD did not sell the stuff I put under my floor

I used XPS “High Load” 30 or 40 IIRC. The 30 or 40 is lbs per square inch I believe. I did not buy it for the compressive strength. I bought it for the near zero water absorption.

If you care to look up the “specs” check out the DOW website.

Best to use Polyiso in the walls & ceiling. But it can degrade under load “especially” if it gets wet (like under a floor).

@GaryBIS did some water absorption tests which showed results I already knew - Polyiso will absorb water.
 

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Careful here; Where the HD guy is technically correct the real answer is it depends;

It depends upon what XPS board you buy. HD did not sell the stuff I put under my floor

I used XPS “High Load” 30 or 40 IIRC. The 30 or 40 is lbs per square inch I believe. I did not buy it for the compressive strength. I bought it for the near zero water absorption.

If you care to look up the “specs” check out the DOW website.

Best to use Polyiso in the walls & ceiling. But it can degrade under load “especially” if it gets wet (like under a floor).
The you didn't have to deal with the styrofoam "helmets" up on the ceiling? Does FMVSS 201 even apply in Canada? Or did you add them back in for the occasional jaunt across the border?
Nope - Our van did not come with them.

We do have styrofoam helmet laws here when riding a bicycle 😳. Maybe I could wear one in my van 😜
 

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Discussion Starter #114
I used XPS “High Load” 30 or 40 IIRC. The 30 or 40 is lbs per square inch I believe. I did not buy it for the compressive strength. I bought it for the near zero water absorption.

If you care to look up the “specs” check out the DOW website.
Found your DOW spec sheet. How thick is what you put on your floor? Having issues finding High Load XPS in thin sheets in the U.S. Closest so far is 3/4" with 25psi (green) and 1" with 25psi (pink), but it is unfaced. (Human footprint is roughly 16psi, so I am comfortable with anything over 20 as long as it is distributed over larger area by plywood top layer.) XPS drops to 15psi at 1/2" thickness. I have already sourced my floor bolts, M8-125 x 50mm, based on my 1/2" poly and 1/2" BB plywood. McMaster has a good selection, so no problem getting longer bolts if needed, but I hesitate to make my floor overly thick.

Might be a regional advantage to living on Canada... colder so better insulation is more readily available.
 

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Found your DOW spec sheet. How thick is what you put on your floor? Having issues finding High Load XPS in thin sheets in the U.S. Closest so far is 3/4" with 25psi (green) and 1" with 25psi (pink), but it is unfaced. (Human footprint is roughly 16psi, so I am comfortable with anything over 20 as long as it is distributed over larger area by plywood top layer.) XPS drops to 15psi at 1/2" thickness. I have already sourced my floor bolts, M8-125 x 50mm, based on my 1/2" poly and 1/2" BB plywood. McMaster has a good selection, so no problem getting longer bolts if needed, but I hesitate to make my floor overly thick.

Might be a regional advantage to living on Canada... colder so better insulation is more readily available.
I use 1” XPS 30 with 3/4” BB plywood on top

I was careful not to kneel or stand on it while installing the XPS or Plywood as it will dent

My XPS is unfaced - It all comes that way as far as I know.

Polyiso comes faced - XPS does not (not normally)
 

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Discussion Starter #116
Not sure where I went off the tracks here, pretty sure I read people were using poly in the floor, but after a better investigation I am open to change. I had some XPS scraps over at the shop that I was going to use to make a nose cone, long story. Had them for a while, but always stored indoors out of sun. IIRC one of them did have a layer of clear plastic membrane on it - I peeled it off years ago in anticipation of glueing squares of it together to make a long block to turn on a spindle for the nose cone.

Not a very scientific experiment, but I took each piece and pinched the corner as hard as I could and noted the deflection. 2" blue (Dow, unlabeled as to density) was the firmest. 2" pink 250 (Owens Corning) was pretty close, even though it was a pretty beat up piece. 1" pink 150 was as strong on the corner as the Dow, but inconsistent along its length. The middle section was significantly more squishy. 3/4" packing styrofoam was the worst by far. Might as well have been furniture cushion foam. The 1/2" Polyiso was better than packing styrofoam, but the worst of the closed cell foam panels. I have been pretty careful not stepping on it while working with it, but I can see it might not hold up to the abuse flooring might give it in compression, let alone water absorption.

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Discussion Starter #118 (Edited)
I found it useful to have channels in the polyiso for things such as cabling. I mention it as it's at the right stage in the build for you and it would be hard to do it later.
Thanks again... I may take you up on that. Having a hard time finding an easy path to get to the side channel (below the black triangle covers) for the 2/0 battery cables, starter battery to house battery DC charger. I can get around the front seat below the footwell plastic cover, but end up above floor level going around the B pillar on the driver side. It may be easier to run along the floor under the cabinets than drill a bunch of holes near the gas fill tube inside the B pillar. TBD
 

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I used the blue stuff “high load”

Even the regular blue is 25 psi & low water & an R value of 5.0 per inch which is a bit less than Polyiso.

I like your “hand squeeze test” above. Doing that you can see that Polyiso will absorb more water & it has the feel is would retain water. Polyiso is reported to breakdown under load especially if wet (& to me it feels like this). I’m sure it is fine under a floor as long as it does not get wet from a leak.

XPS is what is used against foundation walls & backfilled to grade (wet & loaded environment).

Floors - use blue XPS

Walls & Ceilings - use Polyiso




My Blue XPS (2’x8’x1”)
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3/4” BB Plywood on top (1st sheet 5’ x 10’)
*note xps joints staggered 12” from plywood butt joints
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DOW XPS 25psi “blue” specs
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