Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×
 


Reply
 
Thread Tools Display Modes
 
Old 02-02-2018, 11:47 AM   #11
Senior Member
 
Join Date: Oct 2015
Location: Sonoma County
Posts: 781
I'm sensitive to chemicals and you bring up a valid point. Remember the butyl mat will be covered with CCF and then MLV, with all seams taped. HMF is open cell and it's the one step I may omit; it will depend on how much thermal insulation the other steps provide. If not enough, there are other thermal insulation options. In any case I plan to cover everything with an interior treatment to enclose and encapsulate off gassing materials.

__________________
2003 Astro AWD
2005 Tacoma Access cab 4x4
1999 E350 RB 7.3 "Al B. Tross" aka "Exxon Valdez"
SteelheadJones is offline   Reply With Quote
Old 02-02-2018, 02:05 PM   #12
JWA
Senior Member
 
Join Date: Jan 2011
Location: Reynoldsburg, Ohio
Posts: 3,765
Send a message via Yahoo to JWA
Because there's absolutely no way to keep humidity out of our vans so we need to control it, change where it collects and becomes liquid. So far I've found what follows to work very very well. It does not involve multiple layers of matting materials intended more for automotive sound attenuation applied in a way the end result would be an encapsulated body interior hoping to would pretty much eliminate any rust forming inside our finished interiors. Here's what I've done.............

1. Cover the floor with 3/4 plywood, nothing underneath as a first step. Eventually you'll cover this with carpet or something else which is perfectly acceptable, builder's choice here. Installing the plywood over top of the floor ribs you've left ventilation spaces where moist air is not trapped or absorbed. When any sort of absorbent material--think typical automotive-type rubber mats with the spun fiber backing---is left to soak up humidity over a few years it becomes saturated because the water vapor cannot evaporate out. There are more than a few who've seen this when building out a van; unseen rust inside, not a bit on the underside of the floor.

2. Push unfaced fiberglass batting into the lower cavities below the typical horizontal beam, where the body basically becomes a double wall. Loose fill, not stuffed or packed super tight, not necessary to push it below the level of the floor.

3. Over the now-bare steel walls one or two layers of a radiant barrier-type insulation like this: Reflective Insulation | TempShield Double Bubble White Foil Insulation or something similar, adhered to the steel with 3M 80 spray adhesive. (High quality similar products also acceptable to either of those suggestions.)

4. Design/build your finished interior with the thought of creating cavities that can be filled with more unfaced fiberglass insulation batts, these cavities being deep enough to suit your desire for finished interior space. Personally I'd not go more than 4".

What this does is gives humidity an "easier" place to condense with temperature swings. Because humidity will condense on the closest surface you've moved the steel walls further away, the hopes being that will be enough to keep your newly-formed insulated cavities relatively dry.

This isn't a perfect system but its very effective in it's R value and money-wise too. Yes it does utilize common building materials but when they're used properly they work great, little to no chance chemical incompatibility issues will result.

I don't know what outgassing issues might be created by my suggestions but I would think they're similar to those encountered in most new-built homes.

I would add insulation's function is to affect the flow of heat---we all know that. For the most part I disagree a well insulated van would be harder to cool or heat when its interior has reached the ambient air's temperature. Should we return to a vehicle's interior that was reached or exceeded the ambient temperature (greenhouse effect) simply opening the doors or otherwise exhausting the trapped air along with running the A/C and we'd have comfortable temperatures soon enough.

Insulation along with other solar-gain controls would give us vehicles not prone to excessive interior temperatures if their comfort systems are not in use during the idle time.

Anyway sorry to drone on-----hoping even a bit of this is helpful.
JWA is offline   Reply With Quote
Old 02-02-2018, 03:56 PM   #13
Senior Member
 
joefromsf's Avatar
 
Join Date: Sep 2015
Location: San Francisco, CA
Posts: 341
Hey JWA,

How/where would you incorporate sound deadening in the above solution?
__________________
2012 E350 RB XLT Wagon, Agile 4x4, SMB penthouse
joefromsf is offline   Reply With Quote
Old 02-03-2018, 05:25 AM   #14
JWA
Senior Member
 
Join Date: Jan 2011
Location: Reynoldsburg, Ohio
Posts: 3,765
Send a message via Yahoo to JWA
Quote:
Originally Posted by joefromsf View Post
Hey JWA,

How/where would you incorporate sound deadening in the above solution?
Sound deadening inside the cabin comes about in two different ways, the first is plywood on the floor, pretty much 100% coverage there. For a quick test how well this works just by itself drive around in a completely empty van, listen how tin can-like it sounds. Next simply buy or place at least two sheets of 1/2" - 3/4" plywood, MDF etc etc in the rear area, test drive again.

I've never measured the different sound levels but conversations and even the radio don't require as much volume (loudness) as without.

By using the linked radiant barrier insulation as described on side walls and roof you're damping any sounds produced from those panels vibrating, a by-product of simply driving around. Honestly that material used as described isn't that effective R-value wise but its "cheap", not prone to sloughing off the metal when those areas are heated by the sun. Once installed it stays in place, shouldn't out gas at all and not being asphalt based its not the least bit plastic as its heated from solar gain.

I say "cheap" because its cost per square foot is considerably less than many products I've seen used with builds on forums like this one. To my mind the more pricey stuff doesn't do much more than my method apart from running up the finished cost of the project. Most of these materials will be covered so that leaves the question how well do they hold up installed over a few years or longer? (I'm not against spending money for something that works as designed or promised but when something works just as well for me as the higher cost stuff I'll save those dollars to possibly spend in other areas.)

Once the batt insulation is added to the wall/roof cavities, a nice appearing floor covering is in place the noise reduction and insulation is pretty much complete.

Taking things a bit further I've also built and installed 3/8" plywood door panels cut to fit just like the lower level trim packages seen in a typical cargo only van. If you don't use your door cavities for storage as I do filling them loosely with fiberglass batts does wonders for reducing noise that creeps in from those places.
JWA is offline   Reply With Quote
Old 02-04-2018, 09:41 AM   #15
Senior Member
 
marret's Avatar
 
Join Date: Nov 2016
Location: FL and VA
Posts: 1,948
Garage
Quote:
Originally Posted by JWA View Post
Anyway sorry to drone on-----hoping even a bit of this is helpful.
Very helpful to me, thank you very much.
__________________
Chris
2008 GMC 3500 Quigley Weldtec 4x4 Savana SMB
marret is offline   Reply With Quote
Old 02-04-2018, 09:54 AM   #16
JWA
Senior Member
 
Join Date: Jan 2011
Location: Reynoldsburg, Ohio
Posts: 3,765
Send a message via Yahoo to JWA
Quote:
Originally Posted by marret View Post
Very helpful to me, thank you very much.
That's always my goal here and glad to know it is helpful.


J W
JWA is offline   Reply With Quote
Old 02-15-2018, 07:07 AM   #17
Junior Member
 
Join Date: Feb 2018
Posts: 6
I've been researching this very thing for about 6 months now. Here's more or less what I've settled on. (Started my build this week, so insulation is soon.)

*There's a summary at the bottom.


Things to keep in mind:

- Brand new vans are not likely to rust as the paint is fresh, and you'll be covering it. The paint can withstand moisture. Bare metal is what you need to worry about.
- There are multiple types of insulation, as heat can move three different ways: Radiation, Convection, Conduction.
- What climate will you be in? I'm building mine for mixed, but if you're in the desert you'd care less about moisture and more about radiant heat. Make sense?
- I have over a decade of paint and coating experience and work part-time as a handyman. I've also consulted a government PhD space and aeronautics engineer. And I've watched probably 200 hours of van build videos on youtube. So hopefully this info helps!

Things not to do:
- I would NOT adhere any insulation directly to the steel walls. For me, there is great value in the ability to remove panels and check the the painted metal for failures.
- DON'T use Reflectix without an air gap... or at all. Aluminium foil is cheaper per sqft... and the bubble wrap in the center does nothing but add slight rigidity. Don't adhere this to the steel. The plastic of the bubble wrap will 100% degrade over time in the heat. The walls can get to 170°F in the direct desert sun which will not bode well for your expensive bubble wrap.
- DON'T use fiberglass. It causes cancer when you breath it in often. Given the van will be moving around a lot, fiber dust will work it's way in, unless you have a hermetic seal, which no one does... ALSO, and maybe more direct to this thread, it very very very easily traps moisture. This is why Closed Cell Foam is key... also Hydrophobic Melamine is a good alternative.

Remember! -- The engineering around insulation is different for a moving metal can house than it is a wood stationary house. Making walls in a van like you do in a house doesn't make sense.


Layers of progression:

MOISTURE BARRIER FOR STEEL WALLS
First I removed anything along the floor and walls that will ultimately be behind a wall or floor. I sanded down any surface rust to the best of my ability. If you're van is new you'll just need a light scuffing with ~120 grit sandpaper and a soft hand, DON'T break through paint, just dull it.

I am then applying RustOX from Encore Coastings. No VOCs, non-toxic, durable, flexible, waterproof paint made for painting tugboat bottoms and industrial deep-sea oil rigs. Made to stand up to salt water environments, underwater, for years. You'll probably want 2-3 gallons, which should run you around $200-300. You can apply it with a brush, roller, or spray it.

I did this because it's way way cheaper than Line-X or Rhino Liner, I don't need the tread, I wanted to do it myself, and I wanted something made for preventing water, not for adding grip and ding-resistance to a truck. There are other options... (look up EcoPoxy or EcoDur), both are more expensive and may require a pro to do it, but would perform even better.

NEXT IS A RADIANT BARRIER
After researching thermodynamics and consulting my scientist buddy, we decided to apply a layer of aluminum foil --- Not your kitchen variety, but it'd still work... --- I'll be getting mine from AtticFoil. It's thick, durable, etc.

Adding a layer of foil direction to the painted metal will not only add more protection from moisture and elements but also reduce the radiant emissivity of the steel from TERRIBLE, to ALMOST PERFECT. Aluminum blocks 97% of radiant heat. Considering a van is a steel box, that is where the majority of heat enters your vehicle, after windows (which can also get a shiny aluminum barrier and/or Ceramic Window Tint.

You then NEED to have an air gap. I'm using the 1-2inch gap that is already available to me from the ribbing in the van.

** EVERYTHING that touches the aluminum will counteract the barrier effect, since Aluminium conducts heat almost perfectly. So only apply to areas that aren't going to touch other things.


NOW A CONDUCTIVITY BARRIER

Ok, so now I'm adding Closed Cell Foam (won't absorb water, blocks vibration, reduces the conductivity from steel to wood) to the ribbing, and then adding a firing strip.

To the firing strips I'm using 1" Polyiso rigid foam panels. I'm using this because it has the highest R-value of a rigid panel (R-6 to R-6.5 per inch which is better than fiberglass or mineral wool). They come with foil on them. I'll face that foil to the inside for a radiant internal barrier as well.

Polyiso also doesn't hold moisture, is super light, can withstand 270°F, durable when the van is bumping along and lightly flexible. (2" panels will not be flexible).

I'll tape these with reflective duct tape to create a semi-vapor barrier.

INTERIOR RADIANT/CONDUCTIVE/VAPOR BARRIER
Finally, I'll add a ~1/2" firing strip (like a Lath strip for plaster) to create a small air gap for the polyiso foil side, and then to that I'll adhere my wood paneling for the inside of the van. On the back of the paneling I might add a layer of thinsulate or some sort of closed cell foam or Mass Loaded Vinyl as a vapor barrier, not sure yet.

One thign to consider is that a moisture barrier is less useful when you've already sealed the steel, and all your components don't absorb moisture. If you're in a place that's damp or moisture otherwise becomes a problem, you might actually want some air flow to allow it to dry out.

*** To accomplish this, I consider convection. I might stick a small 12v or solar boat vent fan in my roof. If the air gap between the steel/aluminium and my polyiso is moderately connected from side to side and to the ceiling, I can vent that air space which will both eliminate moisture AND use convection to elminiate pretty much ALL heat in the summer. (You'd want the fan to turn off in the winter at night so you don't loose built up thermal energy in the wall...)


SUMMARY
-Steel
-RustOX
-Aluminum
-Air ~2"
-Closed Cell Foam on connection points to dampen sound and conductivity.
-1" Polyiso Rigid Foam
-Aluminium (already on the polyiso)
-Air ~1/2"
-Thinsulate
-Wood

This should give you an R-Value of about R-12 and should pretty much eliminate Radiant Heat gain or loss. Few people talk about or really design for Radiant heat, but when you're living in a metal box, it really ought to be front and center, especially given you only have a few inches to work with.

Hope this helps! I'll be posting my build out either here or on Expedition Portal this week, stay tuned!
ives is offline   Reply With Quote
Old 02-15-2018, 12:07 PM   #18
GAR
Senior Member
 
Join Date: Nov 2016
Posts: 256
You’ll have one of the best insulated vans around. Now you’ll just need a trailer because you won’t have anymore room in the van! Lol, just kidding. Good job and very informative write up!!

Gar
GAR is offline   Reply With Quote
Old 02-15-2018, 01:49 PM   #19
Senior Member
 
Join Date: Jan 2018
Posts: 239
good info and well written - thanks!

john
LosAngeles is offline   Reply With Quote
Old 02-16-2018, 09:27 AM   #20
Junior Member
 
Join Date: Feb 2018
Posts: 6
pure butyl rubber from a good company like Second Skin shouldn't off gas and has a high heat rating.

Hydrophobic melamine is open cell I believe, but is treated (again check out Second Skin) so that water won't want to be absorbed. They have a youtube video showing a demonstration.

Melamine isn't supposed to be super toxic, but they do say you want a vapor barrier after it to prevent any off-gassing from reaching the cabin... .just as they do for glass wool or other insulations, so no difference there.

Unfortunately, months of research have not led me to any truly 'eco-friendly' healthy ways to insulate a van. Eco-friendly seems to assume you aren't moving and you can fully seal away from moisture... things that just aren't true of a van.

I'm starting to think that it's mostly a matter of.... 'can you make it slightly less toxic, and then put a vapor barrier to stop those fumes from getting to you.'
ives is offline   Reply With Quote
Reply

Tags
insulation moisture noise

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

» Featured Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3
Disclaimer:

This website is not affiliated with or endorsed by Sportsmobile SIP or any of its affiliates. This is an independent, unofficial site.


All times are GMT -6. The time now is 04:23 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2024, vBulletin Solutions, Inc.