Need to really start thinking about insulation and climate control

[highdesertranger]

it was from the Prodex site. highdesertranger

 

[DannyB1954]

There are other options other than foam. This individual does a whole series of an Astro van build. Keep an open mind and have a look.
I am not a fan of vapor barriers. I see foam as being one of them. If moisture does get on the wrong side of them, you have problems. Every insulation has drawbacks, so you need to pick the ones that you don't mind as much. Some climates can be warm during the day and below freezing at night. Having some kind of insulation also adds mass to store some heat that comes in handy at night. It also reduces your cooling and heating needs. Reflectix works good on glass, but they also have clear window tint for windshields that works great. (you get to keep your view). It is based on Nano Ceramics.
For hot sunny climates shade is the best. You can put a sheet of outdoor ply over the roof with an air space in between. Add solar panels and you kill two birds with one stone.

 

[TrainChaser]

Waldenbound:  "Ok, let's try this. You're standing in a cargo van, looking at the wall. Take a furring strip, fasten it to the ribs, at the top, middle, and bottom. Horizontally. Three strips.  Take the Reflectix, fasten it to the strip. Then add polyiso, then add plywood.  Than, take the top furring strip, and fasten all of the layers together."

1.  Reflectix only stops the radiant heat that touches it.  No sunlight is going through the skin of your van to touch the Reflectix.  Reflectix is unnecessary, except for window covering.

2. If you don't use the unnecessary Reflectix, you don't need the unnecessary dead-air space.

3. Without the Reflectix and the dead-air space, you don't need to increase the thickness of the walls with the furring strips.  *IF* the distance from the inner wall skin to the rib is 1.25", and your furring strip is a real 3/4" thick, you've lost 2" x 2 walls = 4" of van space.  And that's BEFORE you add anything on top of the furring strips. 

4.  If you install 1" of the polyiso on top of the furring strips x 2 walls, you've lost a total of SIX INCHES.  And you're not finished yet!

5. Then you're talking plywood.  WHY?  If I recall correctly, the thinnest common plywood is  1/4".  It doesn't flex enough to fit the curve of the walls and ceiling, so you're going to lose even MORE space by building a square box in a rounded van, or you're going to be paying the builder quite a bit extra to cut and fit.  Now, if you really meant thin  'paneling', that is thinner (1/8"), and much more flexible.

Please, go back to my last post and read it again.  What part of it do you think won't work for you?  if you want to dedicate the postions of the three 1x3" support strips -- which most people would do -- that would be quicker (and you wouldn't be paying for excessive labor).  With just 1" of the polyiso, you would be getting the benefit of the insulation without losing much space. If you want to cover the polyiso with 1/8" paneling, the cost in space would be negligible.

And, like AlmostThere said, don't worry about moisture buildup -- you're going to have those doors, windows and vents open enough that there isn't likely to BE any moisture buildup.

 

[waldenbound]

Waldenbound:  "Ok, let's try this. You're standing in a cargo van, looking at the wall. Take a furring strip, fasten it to the ribs, at the top, middle, and bottom. Horizontally. Three strips.  Take the Reflectix, fasten it to the strip. Then add polyiso, then add plywood.  Than, take the top furring strip, and fasten all of the layers together."

1.  Reflectix only stops the radiant heat that touches it.  No sunlight is going through the skin of your van to touch the Reflectix.  Reflectix is unnecessary, except for window covering.

2. If you don't use the unnecessary Reflectix, you don't need the unnecessary dead-air space.

3. Without the Reflectix and the dead-air space, you don't need to increase the thickness of the walls with the furring strips.  *IF* the distance from the inner wall skin to the rib is 1.25", and your furring strip is a real 3/4" thick, you've lost 2" x 2 walls = 4" of van space.  And that's BEFORE you add anything on top of the furring strips. 

4.  If you install 1" of the polyiso on top of the furring strips x 2 walls, you've lost a total of SIX INCHES.  And you're not finished yet!

5. Then you're talking plywood.  WHY?  If I recall correctly, the thinnest common plywood is  1/4".  It doesn't flex enough to fit the curve of the walls and ceiling, so you're going to lose even MORE space by building a square box in a rounded van, or you're going to be paying the builder quite a bit extra to cut and fit.  Now, if you really meant thin  'paneling', that is thinner (1/8"), and much more flexible.

Please, go back to my last post and read it again.  What part of it do you think won't work for you?  if you want to dedicate the postions of the three 1x3" support strips -- which most people would do -- that would be quicker (and you wouldn't be paying for excessive labor).  With just 1" of the polyiso, you would be getting the benefit of the insulation without losing much space.  If you want to cover the polyiso with 1/8" paneling, the cost in space would be negligible.

And, like AlmostThere said, don't worry about moisture buildup -- you're going to have those doors, windows and vents open enough that there isn't likely to BE any moisture buildup.

Here's my current idea for when I get my van (unless I change my mind a few more times):

Train Chaser posted:

1. I'm probably going to use multiple layers of 1/2" polyiso, because that thickness is much more flexible than the thicker ones, and will bend to fit the curves of the van, thus preventing having to make multiple cuts to do the same job. Home Depot prices: $19.25 for the rigid 1" thick, and $11.47 for the 1/2". Using two sheets of 1/2" costs $3.65 more to cover the same area -- I can live with that difference to avoid more work. I plan on building up the polyiso to be level with the ribs.

2. I will probably be using fir 1x3s to cover the ribs. It's R value is only about 1.0, but it's better than raw metal. I'm not expecting perfection. If the weather is good and I have the time and initiative, I may stain the 1x3s so they look like 'day-core'. Or not.

3. Many/most of the van ribs have holes suitable for bolts. Before the wood is put in place, I need to mark the vertical wood strips to show where the holes are. Since I have been known to change my mind Rolleyes , I will be marking most of the holes so I'll know where they are when I want to add or move the strips, but will only be drilling the holes that I have immediate use for . Then I need to decide where I will want to install the horizontal support strips. These strips will have different things attached to them: cabinets sitting on the floor to hold plastic totes (etc), maybe to hold the platform bed in place so it doesn't shift, maybe hooks on the upper strips or shallow cupboards.

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Holy cow, now I'm really confused. :s :-/
Ok, so now we're saying Reflectix is useless on the walls, just windows. Well, yes I'm going to have Reflectix on the driver and passenger side windows, the windshield. But cargo vans don't have side windows many times.

Train Chaser, so you're saying forget the Reflectix entirely for metal. Just 1/2 polyiso between ribs. Then 1x3 fir on top of the ribs.
That sounds reasonable.
The reason why I want thin plywood over the walls is because I want a finished look. I don't want to live in a construction worksite. I saw some at Lowes that was very thin, it was something I could live with, and it wasn't much money. So either thin plywood or paneling.

Ok, I have to go to work today. I'll be back later this afternoon.
Thanks to everyone who is helping me figure this out. It's like this is the one thing that baffles the daylight out of people. Or me, at least.

PS, I'm not worried about moisture at all. That what them two fans are for. They're also to keep me from looking like baked rump roast during July and August.

 

[Optimistic Paranoid]

1.  Reflectix only stops the radiant heat that touches it.  No sunlight is going through the skin of your van to touch the Reflectix.

I'm not a fan of Reflectix.  My personal opinion is that you should just fill the walls of your van with polyiso and be done with it.

But you've got the physics wrong.  Anything that gets hot radiates heat.  The sun beats down on the outside of your van.  The metal skin gets hot.  The hot metal walls WILL radiate heat to the inside of your van.  A reflecting surface will prevent this radiant heat from reaching the inside.  But so will polyiso insulation in contact with the metal skin.

 

[Almost There]

1.  Reflectix only stops the radiant heat that touches it.  No sunlight is going through the skin of your van to touch the Reflectix.  Reflectix is unnecessary, except for window covering.

Reflectix stops heat from transferring through it in to the inside of the vehicle.

Sunlight has nothing to do with this. Any type of heating unit would act the same. I could put an electric heater aimed at the outside of my van and create the same effect, albeit in a reduced area. it is not the sunlight itself, it is the heat from the sun.

If used with no air space against a metal wall then conduction transfers the heat from one layer to another thereby rendering it useless.

When used with a DEAD AIR SPACE, reflectix does what it was designed to do...it stops heat transfer. Note that I said 'dead air space'. If the space allows air movement, then the heated air escapes past the reflectix, defeating the whole process.

As a window covering, it also works as it reflects the sunlight back to the outside through the glass. This is different than blocking heat transfer.

 

[DrJean]

How about this: 

put the polyiso  (two 1/2" layers) on the metal van followed by the Reflectix over the entire area, ribs included.

 This way you don't have the radiant barrier heating up when it should be temperature assisting, and you have a sealed vapor/moisture barrier (assuming you seal it well with the respective tape) covering even the metal ribs (which can condensate or heat transfer on their own).

I mean, if you wanted the polyiso showing for other enhancement, you could put one layer next to the metal (sprayed on with 3M 80 or 90) then the Reflectix, then the other polyiso.  Just be sure to cover the ribbing when you run the Reflectix over the metal.

?

 

[highdesertranger]

couple of points, you can get 1/8 inch plywood/paneling it bends easy. I worked converting vans back in the day, I have converted hundreds of vans and have seen thousand of more converted. I have never seen furring strips used. highdesertranger

 

[DrJean]

I've looked at both Luan and Coroplast for a "final" layer...


I really, really think everyone doing this should consider a vapor barrier.  Maybe if you stay in dry climate and keep your doors open you won't have any issues... but truly condensation does build up even on cool mornings on the windows, and your CO2 emissions even while you sleep creates moisture.

Just check into it, ok?   It's imperative if you use certain insulation,  imo.  

[url=https://buildingscience.com/documents/digests/bsd-106-understanding-vapor-barriers]Understanding moisture barriers[/url]

 

[TrainChaser]

Okay, please answer this: If you had two identical vans, and lined one with a layer of Reflectix (R 1), and one with 1" of Polyiso* (R 6) and nothing else, which one would have the best effect in a) heat, or b) cold?

*I am planning on using 2- 1/2" sheets with the foil facing, with the foil of the first sheet touching the van skin, and the second sheet with the foil facing the inside of the van.

I want to do this the SIMPLEST WAY possible, not the most complicated.

 

[DannyB1954]

What happens when moisture gets on the wrong side of the vapor barrier and can not evaporate easily?
When it rains water slides down the driver's and passenger's windows and at least some of it goes inside of the doors. There is a plastic vapor barrier that keeps the inside door panel from getting wet, (the inside door panel is usually made out of some type of cardboard). Because there is air circulation and the water can evaporate seldom is there a problem of the outside steel door skin rusting through. In a house it is mandatory in an attic where moisture might get in that there is an air space above any insulation so that any moisture can evaporate out.

It makes no sense to me that people recommend and even say it is imperative that people trap moisture in between two vapor barriers, (the metal of the vehicle body, and some kind of plastic vapor barrier such as Reflectix). Moisture will get in there, and if it can not get out, you will have a problem. Vehicle manufacturers have been using a fiber insulation to keep out engine heat and noise out of the passenger compartment for many many years. Maybe some expert should tell them to use foam and a vapor barrier instead.

 

[waldenbound]

Im really leaning toward TrainChaser and Optimistic Paranoid's consensus on the polyiso, two layers of 1/2 inch. Over complicating things will just cost more time and money, not to mention frustration.

highdesertranger, I need furring strips or something to serve as wall studs. I need hooks to hang things in camp. My stuff is ultralight but I'm not trusting polyiso and thin plywood to hold things.

I'm not really worried about moisture, there's plenty of ways for ventilation.
When I'm out camping, if I have my tent sealed up tight, I'm going to wake up to a soggy, drippy tent in the morning. If I have ventilation, like unzipping the doors a little, or using the ventilation on the rain fly, no condensation, a dry tent.

 

[DrJean]

Don't complain to me about physics: talk to Newton for that (or God)? :

One does have to seal the barrier, or it isn't a barrier.

As for reflectix, it's too expensive for what it touts. There are other products...

There isn't an R value rating for foil itself because it needs to be installed WITH an air layer... it's the combination that creates any kind of "R" factor.  That's why you add something like polyiso...but whether to go with closed or open cell ??>

If you put foil on the metal it will resonate with the heat and bring the heat right into the van in the summer.  Like wise in the winter, if it is the only layer, it will heat up inside and pass that heat right on out your van (roof)...  You need the thin "foam" in some form next to the metal to stop this heat transfer.  Then you need the "air gap" between the foil and the finished roof lining so that you can have an "R" factor of some type.

The van won't be air tight, but if you work at not having a thermal bridge by  overlapping and taping and sealing a layer as best you can, you will gain the best insulating you can get.

Metal condensates, as does glass, unless you do something to prevent it.

 

[ArtW]

I'll just leave this here
http://www.cheaprvliving.com/conver...-conversion-part-2-insulation-flooring-solar/

 

[HaidaBoy]

Hello Folks,
Just did my 10x6 cargo trailer walls and ceiling with ECO FOIL, reflective barrier. ( ecofoil.com ).  I reflects 96% of radiant heat, is reflective on both sides (keeps heat out or heat in), and also is a quality moisture barrier. It is very strong and easy to work with, and can be applied with staples or spray adhesive. I kept the air gap all the way around which is crucial. And it costs around $70 for a 4 ft. x 125 ft roll. Will also install under trailer floor when it is replaced next summer.
To keep the aluminum roof sealed and quiet, I also used Gaco 100% silicone roof coating. Great stuff, $90 a gallon. will cover a 10x6 roof easily with 2 coats of pure white reflective silicone.

 

[DrJean]

Perhaps the rubber coating on your roof would prevent condensation and heat transfer through the foil???

 

[HaidaBoy]

Perhaps the rubber coating on your roof would prevent condensation and heat transfer through the foil???

With 96% of the outside radiant heat reflected outwards and 96% of the inside radiant heat reflected back inwards, along with a vapor barrier, I'm not sure if condensation is going to be a big issue. IMHO. 
The roof was weather proofed for reflective and sound barrier reasons. Rain can sound like drums on a bare aluminum roof.
With the roof being coated, I guess the Eco Foil will work even better, hopefully. The installation was a breeze and very clean.
And I don't have to breath all that toxic vapor that form board puts out. When out in the sun, the outside of the trailer is very warm, while the inside is cool.

 

[TrainChaser]

Waldenbound: " I need furring strips or something to serve as wall studs. I need hooks to hang things in camp."

Once you've got your polyiso in place, just attach some 1x3s across the vertical ribs.

 

[Solitary Spell]

I love that guy's videos, he's great!!