Heavy Wood, Reflectix & Insulation

[PattySprinter]

I am planning on getting a van early January to go to the RTR. I have watched probably over 100 van build videos and the weight of all that wood in the paneling, roof, floors and furniture is worrisome; how will it impact my gas consumption???? Luan looks light ... and could be an asset to hold in insulation.
 
But how important is insulation?? I think I heard Bob W. say on a video that it is good in the ceiling but not necessary elsewhere.
 
I have seen also where people say there has to be a gap (insulation) between van wall and reflectix (except on windows).
If this is correct then why is the reflectix contacting the van walls on so many builds?

Last question for this post - I have a stack of large foil 'bag' used by Sprouts to transport cold groceries - can I repurpose those effectively instead of using reflectix?

Thank you for reading )

 

[RVtrek]

But how important is insulation??

I went to RTR last year in a cargo trailer that had no insulation.  Let me tell you, from experience: insulation is very important.

I'm currently building out that same cargo trailer and I'm adding 3" of Poly-Iso insulation all the way around.  PolyIso is very light weight, has a great R-value, and if you buy it thin enough it's somewhat flexible to the walls of a van.

If I were building out a van, I'd add as much insulation as I could, then throw some Luan on top (or other surfacing material).  I personally like staying in cooler climates where running some kind of heat is needed on occasion, so having good insulation transforms the experience from the feeling of homelessness to comforting.

 

[John61CT]

Yes most carry too much unecessary weight, not just mpg but more important suspension wears faster. Better to think like a backpacker, but pounds rather than every ounce.

Roof is most important, floor least, none at all crazy for most.

Any reflective foil will do for the outside of your window covering, more durable the better.

Yes it is useless jammed behind paneling, no good without a decent airgap, or left exposed pointing in.

 

[PattySprinter]

I went to RTR last year in a cargo trailer that had no insulation.  Let me tell you, from experience: insulation is very important.

I'm currently building out that same cargo trailer and I'm adding 3" of Poly-Iso insulation all the way around.  PolyIso is very light weight, has a great R-value, and if you buy it thin enough it's somewhat flexible to the walls of a van.

If I were building out a van, I'd add as much insulation as I could, then throw some Luan on top (or other surfacing material).  I personally like staying in cooler climates where running some kind of heat is needed on occasion, so having good insulation transforms the experience from the feeling of homelessness to comforting.

Thanks Michael - I will go to Home depot and check out Poly-Iso.

 

[PattySprinter]

Better to think like a backpacker,  but pounds rather than every ounce. 

Thanks John - I like that thinking track.
 
I want as little weight as possible - but also want to make sure the bed, stove, water, propane and other items and battened down safely.

 

[John61CT]

Yes, a "loads secure" checklist before rolling out is critical for this forgetful fool.

Some rely on a bulkhead. . .

 

[Gideon33w]

The impact of the weight will depend on vehicle type. Heavy duty work vehicles like full size trucks and vans have the least impact as they have gobs of torque and lower gearing. Whereas a minivan can take a large percentage hit from the weight penalty. Also, keep in mind that different people have different types of rigs and therefor a variety of carried weight. But yes, adding weight will always negatively impact fuel economy.

Insulation is more helpful when battling cold versus heat. It's also much easier to add heat than add cold. Ventilation trumps all when it comes to fighting the heat. Beyond that, you can get a lot of benefit from judicious use (and correct use) of radiant barrier (like reflectix) and I saw a MASSIVE improvement here in Arizona by coating my roof in a reflective coating designed to keep houses cooler.

Keep in mind that a radiant barrier product only works when there is a gap. You see a lot of people with this product direct to van walls because they don't understand this fact. The material is now acting as a radiant barrier only one way (interior to exterior) whereas you want it acting both ways preferably. Barring that, better to have it working one way exterior to interior versus the opposite.

Those bags are a radiant barrier and will do the same job. Heck, if you want something far simpler you can do what I did and laminate the back of your paneling with space blanket material.

Keep in mind, the idea of converting a vehicle is ALL about compromise. Every choice is a compromise. Add insulation and lose space. Add nice interior and lose fuel economy. Etc etc etc

 

[Almost There]

I am planning on getting a van early January to go to the RTR. I have watched probably over 100 van build videos and the weight of all that wood in the paneling, roof, floors and furniture is worrisome; how will it impact my gas consumption???? Luan looks light ... and could be an asset to hold in insulation.

Luan is light and is great for walls and ceiling covering. I put vinyl with 1/8" closed cell foam over the luan to give me the interior finish I wanted. Where I was painting it I used 1/4 plywood because Luan doesn't paint very well IMO. There were places where I should have used heavier wood than I did because I've had to brace it - the front wall of the pantry is a good example of that. 1/2" plywood was used throughout except for the bed top that I used 5/8" for. I didn't want it bowing between supports. If you take a look at my build you'll see that 1/2" plywood is standing on it's side to build the compartments under the bed. Too many use 2x4 throughout. That's fine if you're 20 and are expecting 2 full size adults to be playing bouncy bouncy on it...otherwise it's overkill.
 
But how important is insulation?? I think I heard Bob W. say on a video that it is good in the ceiling but not necessary elsewhere.

Whether insulation is important depends enitrely on where and when you plan on using the van. If you're just out on weekends in the summer camping in the forest then I'd say skip the insulation. If you're staying year round in MI, then you  need good insulation for the winter. Insulation is to keep the heat in when you are heating the interior. It doesn't do a whole lot to keep the heat out in the hot sunshine. That's where a radiant heat barrier comes in to play.
 
I have seen also where people say there has to be a gap (insulation) between van wall and reflectix (except on windows).
If this is correct then why is the reflectix contacting the van walls on so many builds?

Too many people, sad to say, don't do their own research and rely on YouTube videos that virtually anyone of any skill level, can make. I went right to the manufacturers' website and read up on the installation methods for steel buildings because that was the closest I could come to a van. I am quite happy with the result - I installed Reflectix over bubble wrap for dead air space with no additional insulation because I try my best to stay in warm climates year round, hence no real need for traditional insulation. The reflectix over a dead air space performs as it was intended to do.

Last question for this post - I have a stack of large foil 'bag' used by Sprouts to transport cold groceries - can I repurpose those effectively instead of using reflectix?

Maybe - maybe not. That depends on the quality of the bag...compare it to reflectix in the store and see what you think. I suspect it's probably too thin but maybe not.

Thank you for reading )

 

[Gideon33w]

Great info from AlmostThere. But a radiant barrier need have no thickness to work. Hence why space blankets work so well despite being only a couple mils thick. Those foil lined bags are the exact same thing. Heck, regular plain ol tin foil will work and can be attached to the paneling with spray adhesive like I used for the space blanket mylar material. I just already had the space blankets.

 

[John61CT]

There are only two locations where a radiant bartier isn't a total waste of time and money.

Facing in with no covering, living in a Mylar cocoon.

Or facing out just inside the body sheet steel, with an air gap between.

Jammed up against that steel, or between you and the foam but covered with luan or anything else, don't bother does nothing at all.

Best of all is a big tent of the stuff high above your vehicle facing the sun and outside world. But not blocking breezes.

 

[Gideon33w]

Laminating the back of the paneling works as it's "facing" out but air-gapped off the body and windows.
I'd MUCH rather that than just a few millimeters off the body panels.
There's a good 3" between my mylar backed panels and the windows on my Express.
Mind you, I also left a gap at the top so heat doesn't build up and can instead be vented out.

 

[John61CT]

If facing out should be outside any insulation.

Over windows should not have an air gap.

If facing out but it's inside the insulation, does nothing.

 

[Gideon33w]

My van has no insulation. Exterior, air gap, mylar, paneling, interior.
Still need an air gap to work when dealing with windows.

 

[Gideon33w]

https://vanlivingforum.com/showthread.php?tid=25200

&

https://vanlivingforum.com/showthread.php?tid=25199

 

[John61CT]

My van has no insulation. Exterior, air gap, mylar, paneling, interior.

Aha, OK then, for mild conditions I s'pose.

Still need an air gap to work when dealing with windows.

Sorry no, you're allowing the incoming radiant energy to heat that inside air, completely counterproductively.

Best if the foil just turns it around right at the glass sends it back out. Ideally with a foam backing on the inside against the energy (separate issue) getting conducted through.

 

[Gideon33w]

I live in Arizona. Not exactly mild, haha. But obviously geared towards fighting the heat versus the cold.

You're misunderstanding how radiant heat works and what it is. Why would the air on the other side of the glass function differently than the air outside the van? The answer is that it doesn't. The radiant energy passes through the glass (or is distributed on it), the waves travel through the air, and are then reflected back out via the radiant barrier.

 

[Gideon33w]

This should be a sticky - http://www.radiantbarrier.com/physics-of-foil.htm

 

[RVtrek]

Thanks Michael - I will go to Home depot and check out Poly-Iso.

Just to make sure you're looking at the right product, you'll want to look at Rmax Thermasheath, in whatever thickness you think will work best for you.

My recommendation is to use the PolyIso in the ceiling / walls and some reflectix for the windows.

 

[John61CT]

You're misunderstanding how radiant heat works and what it is. Why would the air on the other side of the glass function differently than the air outside the van? The answer is that it doesn't. The radiant energy passes through the glass (or is distributed on it), the waves travel through the air, and are then reflected back out via the radiant barrier.

You're right, radiant energy is heating the air in your gap, just as it does outdoors, but which you actually don't want inside the glass.

And you're right the foil can bounce radiation right back out the glass. Bigger the gap the less effectively it's able to do that.

But I won't argue the point further, can not a major factor overall in your case since you have no real insulation anyway.