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Discussion Starter #1
The membership seems a reasonable option since I plan to mine the forums over the next few years for the excellent knowledge here.

So far- Ive ordered a maxxair 7500k and plan to use the Eric Thorensen plan to brace and install it.

Insulation is the second major install I plan to do this summer;

For the walls I'm considering a 1' polyiso board held on by vertical beads of great stuff adhesive (leaving the edges open for draining) and 1 or more inches of polystrene board glued to the polyiso board to aid in cooler temp insulation.
Seems less scary than trying the spray foam DIY job.

Filling the ribs with thinsulate to allow for wiring modifications.

For the ceiling I have some nice maple laminate flooring which I can brace on the ends and add a polystrene sheet on top and again a polyiso board topped by one inch of greatstuff against the ceiling ribs.

comments, ideas and experiences?
thanks for reading
 

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Discussion Starter #2 (Edited)
slowly



the wood surround for the maxxair went smoothly until I lost confidence in the choice of hardwood which seemed to splinter or split with every screw; decided not to be surprised by the install and replace the wood pieces with softwood, except for one piece.

Thinking a thin bit will make good pilot holes for the roof screws.

http://imgur.com/a/lMnJ1

the panel fasteners came out easily with a claw bar although it slips easily and required some touching with paint primer.
 

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2014, 138WB, High Roof, Gas, SW MT
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Hi,
The down side of leaving drainage channels behind the polyiso is that it will let water vapor laden air from inside the van will be able to reach the van metal skin and condense on the cold van outer sheet metal. I'd think about using enough Great Stuff (especially around the edges of each polyiso panel) to seal it to the van sheet metal and prevent water vapor from getting behind the polyiso.

Gary
 

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Discussion Starter #7
Hi,
The down side of leaving drainage channels behind the polyiso is that it will let water vapor laden air from inside the van will be able to reach the van metal skin and condense on the cold van outer sheet metal. I'd think about using enough Great Stuff (especially around the edges of each polyiso panel) to seal it to the van sheet metal and prevent water vapor from getting behind the polyiso.

Gary
I was thinking to keep the edges of the polyiso open so the condensation has somewhere to go - downward to the drain holes...
 

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2014, 138WB, High Roof, Gas, SW MT
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I was thinking to keep the edges of the polyiso open so the condensation has somewhere to go - downward to the drain holes...
Hi,
Right -- its another one of those van insulation questions...

Do you try to prevent condensation from ever occurring on the van skin by using an insulation (polyiso) that is impervious to water vapor and then sealing it to the van skin with Great Stuff that is also impervious to water vapor.

Or, you just say that some condensation is OK as long as it has a way to drain out and dry out.

I took the first approach, but can't say for sure its the best way to go.

Gary
 

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Hi,
Right -- its another one of those van insulation questions...

Do you try to prevent condensation from ever occurring on the van skin by using an insulation (polyiso) that is impervious to water vapor and then sealing it to the van skin with Great Stuff that is also impervious to water vapor.

Or, you just say that some condensation is OK as long as it has a way to drain out and dry out.

I took the first approach, but can't say for sure its the best way to go.

Gary
Vehicle panels condense all the time here in the NE and in the NW I expect. I took the view that if it can re-evaporate and drain down it is "normal" for the vehicle. I don't have an answer either, except if I failed to do a perfect job the water can get out and if you seal it all around and fail to do a perfect job it is trapped, at least that was my thinking.
 

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Discussion Starter #10
Vehicle panels condense all the time here in the NE and in the NW I expect. I took the view that if it can re-evaporate and drain down it is "normal" for the vehicle. I don't have an answer either, except if I failed to do a perfect job the water can get out and if you seal it all around and fail to do a perfect job it is trapped, at least that was my thinking.
Since my van sat on a lot for 2 years and looked perfect I figure the condensation and drain holes must work okay. When its camping it may be more vapour but the lousy door seals must have let lots of moisture come and go too.

For the ceiling I'm trying for a sealed polyiso with the foil facing the the floor;

for the walls I'm trying the foil facing the van skin with a little felt chair foot (for laminate floor) buried in the dollops of great stuff to make a spacer
 

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I believe BOTH sides of any Polyisocyanurate I have seen has foil, one side is shiny and the other is matt but both are foil covered. It won't matter.
 

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Discussion Starter #12
One step forward....
Did four wall panels with five dollops of great stuff each (gap and crack) around a felt chair foot, (1/4 inch disk). Then put foam on the sides of the panels.
This morning I saw the dollop marks showing on the outside of the van, tore the panels out and the van walls returned to normal. I figure it was a mixture of using regular great stuff, large dollops and the side bars of great stuff to seal the panels. I have used the window and door great stuff on earlier panels on the sliding door and had no problems....
Next - redo panels with modest dollops of window and door great stuff and no side fill. The residue from the dollops I removed will act as a spacer against the van skin.
....a step or so back
 

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Discussion Starter #13
for the walls I'm trying the foil facing the van skin with a little felt chair foot (for laminate floor) buried in the dollops of great stuff to make a spacer
the regular great stuff is too hard on the van skin, now changing to window and door great stuff
 

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Discussion Starter #14
the regular great stuff is too hard on the van skin, now changing to window and door great stuff
and leaving out the felt chair footers; they suck up the moistur of the greatstuff making it rather brittle, and therefore to hard on the tender van metal....
 

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WAY to much great stuff! I did vertical and across the roof strips of great stuff probably 3/4 of an inch wide about every 6 inches then I pushed the polyiso. up to the roof or onto the wall for 3 hours or so .... then I put a small bead 1” or less around the perimeter. I use a Pro gun not the cans and I would advise against the cans as there is no control so you get way too much. It probably took me 6 hours to do all the walls and most of the ceiling. I cannot see any deflection of the metal. I then fit the scraps into the ribs wherever I could get it in which was a lot of places, Then I did the rear doors below and above the windows and the side door above and below too. It was amazing where I could put the strips if I cut them short and sprayed on great stuff and fit them in and pushed them along with the next piece. Perhaps 2 days total. Wow! Good luck in the rest.
 

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Discussion Starter #17
WAY to much great stuff! I did vertical and across the roof strips of great stuff probably 3/4 of an inch wide about every 6 inches then I pushed the polyiso. up to the roof or onto the wall for 3 hours or so .... then I put a small bead 1” or less around the perimeter. I use a Pro gun not the cans and I would advise against the cans as there is no control so you get way too much. It probably took me 6 hours to do all the walls and most of the ceiling. I cannot see any deflection of the metal. I then fit the scraps into the ribs wherever I could get it in which was a lot of places, Then I did the rear doors below and above the windows and the side door above and below too. It was amazing where I could put the strips if I cut them short and sprayed on great stuff and fit them in and pushed them along with the next piece. Perhaps 2 days total. Wow! Good luck in the rest.
More pics coming, the metal deflection on the wall panel mostly corrected, but in the morning as the temp rises a little of the distortion shows up. I suppose I should go back into that section and shave the rest of the residue
but its in an area where there were a couple of small dents from use as a dealership Pantechnicon.

The manga cake load of great stuff was for the ceiling panels which I wanted to seal completely for the moisture issue.
The wall panels I used less and less of the foam and no trim around the edges to allow the condensate to run.

Next, Im thinking thinsulate for the ribs and running light section; I too have been feeding scraps with foam into the upper wall areas on the slider side but the smaller holes on the other side look like work.
 

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If you end up grinding/cutting/sanding anywhere (wheel house tubs) a trick to get the weather-tite glazed coating back on is rub some freshly sprayed foam into the pores, makes a hard shell that armors up the layer nicely. I used that with the window/door flavor - not sure how it would work with more lethal foam-in-a-can varieties.

Wow, I so dislike telling folk to spend money but... Invest in an applicator gun - the manly-man do it straight out of the can is so caveman :cool:

3M 90 is rated to 250°F; coat both foam and sheetmetal then meander a quick bead of foam around the perimeter, slap it up and press and massage the board until the adhesive it quits crackling, about 45 seconds... then the 3M 90 holds tight, the foam cures in place and strengthens boards grip up while making an O-Ring style seal to dodge possible water much later on.

The iso panels can be gently curved to better match the roof curvature, just lots of little press actions over your knee and it will not fight back against the curve, a couple minutes attention w/ 3M 90 & foam with definitely no prop rods needed.

Coming back later and grouting around the foam boards is very satisfying.

I used 5mm thick strips of prodex to fill the roof corrugations, they slid under the trusses so they are continuous 12-foot lengths.
 

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Discussion Starter #20
If you end up grinding/cutting/sanding anywhere (wheel house tubs) a trick to get the weather-tite glazed coating back on is rub some freshly sprayed foam into the pores, makes a hard shell that armors up the layer nicely. I used that with the window/door flavor - not sure how it would work with more lethal foam-in-a-can varieties.

Wow, I so dislike telling folk to spend money but... Invest in an applicator gun - the manly-man do it straight out of the can is so caveman :cool:

3M 90 is rated to 250°F; coat both foam and sheetmetal then meander a quick bead of foam around the perimeter, slap it up and press and massage the board until the adhesive it quits crackling, about 45 seconds... then the 3M 90 holds tight, the foam cures in place and strengthens boards grip up while making an O-Ring style seal to dodge possible water much later on.

The iso panels can be gently curved to better match the roof curvature, just lots of little press actions over your knee and it will not fight back against the curve, a couple minutes attention w/ 3M 90 & foam with definitely no prop rods needed.

Coming back later and grouting around the foam boards is very satisfying.

I used 5mm thick strips of prodex to fill the roof corrugations, they slid under the trusses so they are continuous 12-foot lengths.
I just picked up some sample pine panelling in 4inch x 8ft strips. very light weight. Im going to test it on the ceiling and walls with just adhesive.

and - I do have a gun; however half the Great stuff was on sale in straw top cans. Use the foamgun in the vehicle and the other on the sheathing
 
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