My insulation theory, take a look.

[evy]

Hi everyone,

Please read this post completely before giving me your opinions, thanks!

I'm working on my very first DIY camper conversion, using a 2010 extended Ford E250.

At this moment the floor, upper wall and ceiling are insulated.
The lower walls, doors and wheel wells aren't insulated yet.
But before insulating the lower walls I wanted just wanted your opinion on this subject, I know insulation has been debated over and over.





I'm an Architectural technician so I know a little bit about insulation but this is not a house, I don't believe in Reflectix (sorry I know a lot of you do) I don't even consider it to be insulation, it's basically a thermal bridge breaker, I'm not saying it doesn't work, I just don't want to use it.

Also I know there's a lot of people afraid of polyurethane foam, there's some talk of panel warping, I'm aware of that, from what I have learned there's 2 main reasons for that, the insulation company that did the upper walls and ceiling of my van told me that the temperature of the polyurethane coming out of the nozzle is something like well over 200 degrees and that's why the panels warp (from the heat).
The other reason is expansion, when the foam is trapped it won't stop expanding and will warp the panels.

I have red many many articles here and there on the net and I think that's what it comes down to.

So here's my theory, take a look at my drawing, it's a section of the outer wall and floor.

I plan on using a different and relatively new product : Sika post fix



You can see it in action here :

https://www.youtube.com/watch?v=r9J2Rec2MjE

But the idea is to pour it in small layers of 4 to 6 inches (expanded) maximum at a time (that's my opinion) so the expansion would only be towards the top, So I would start pouring at one end making my way towards the other end, pouring it through the holes on the inside of the walls waiting 24h in between layers. Also I have a lot of scrap foam boards/pieces laying around, I would brake them up in small pieces and put them inside the panels, the expanding foam would fill the void in between the pieces, also I would need much less of that liquid post fix polyurethane.

So there's my theory... what do you think about it?

I'm actually waiting to do this because it's still pretty cold up here.

p.s. remember when using spray foam like the kit they sell at the home depot, you have to be 16" away from what you are spraying it on, you can't just stick the nozzle inside one of the inner panel holes and press the trigger till you see it popping out.

[dhally]

I guess I would wonder what is the insulating value vs. Fiberglass or polyurethane. It isn't sold as insulation- it may not have good properties? A secondary issue might be weight. It could add more weight than other insulations.

[witoke]

Hmmm, I think your theory is good and will work. Though if you are worried about the foam 'over' expanding and putting externally visible pressure on panels, the addition of the blocks might actually end up restricting the foams possible expansion routes. It might be safer to use more of the foam.

You probably already know this, but there are several kinds of foam you can get, the biggest difference for this discussion, is the amount and duration of the expansion. Slow rise foam, used for filling the voids in concrete block and other applications where over-expansion can cause problems, might be worth looking into.

I think the idea is great and if done carefully with small pours, should give you exactly what you want. Just don't get moisture trapped in the cavity before you pour and maybe even spray inside the cavities with Waxoyl or something. I have heard rumors that it's often cold and damp up there.

[hein]

3M Thinsulate(TM) is a great choice for insulating vehicles. It's engineered for the application and passes all pertinent Federal Motor Vehicle Safety standards. Honda and Tesla and other OEMs use it. Easy to install, no smell, absorbs no moisture and offers noise blocking, resonance (structure born noise) reduction and thermal in one product.

[JWA]

Hoping you'll pay close attention here.........general observations.....

Any form of spray insulation UNLESS specifically formulated for automotive use, especially in eventually concealed areas behind interior trim should BE AVOIDED! In your case Evy the upper fiberglass cap can/will easily accommodate the spray in foam as it won't react detrimentally with that material as it would against body sheet metal.

Cavities before the mid line of the standard E-Series van can be filled with bat-type fiberglass insulation. Not stuffed in, just laid in to act as its intended to do. I've done this but keep it no lower in the cavity than the level of the factory floor.

I've used a foil, bubble wrap and PVC sheet sandwich radiant barrier insulation applied directly to the inside sheet metal. In your case this could be used over the fiberglass insulation filled cavities, no real need or huge benefit to covering the wheel wells assuming those will be covered with seating or a bed of some sort.

Plywood over the floor is better since it leaves small channels for air circulation. One huge problem with cargo-only vans that leave the OEM padded mats in place is the padding absorbs humidity, eventually becoming saturated and causing rust to form completely out of sight.

The plywood is more than enough insulation since heat rises anyway and if using 3/4" it kills road noises unbelievably well.

As a matter of general opinion ANY material not specifically automotive related is a huge no no. The Sika product would NOT be a good choice regardless how carefully you plan on applying it---its not intended to use used for your intended use. Because of this the longer terms effect of this product used contrary to its intended use is unknown, not really worth the risk of it causing damage to the body even if it's expansion can be controlled.

I hope you consider this seriously before going forward---its not something I'd feel comfortable with knowing there are too many potential downsides using the wrong materials.

[evy]

Originally Posted by witoke

Hmmm, I think your theory is good and will work. Though if you are worried about the foam 'over' expanding and putting externally visible pressure on panels, the addition of the blocks might actually end up restricting the foams possible expansion routes. It might be safer to use more of the foam.

You probably already know this, but there are several kinds of foam you can get, the biggest difference for this discussion, is the amount and duration of the expansion. Slow rise foam, used for filling the voids in concrete block and other applications where over-expansion can cause problems, might be worth looking into.

I think the idea is great and if done carefully with small pours, should give you exactly what you want. Just don't get moisture trapped in the cavity before you pour and maybe even spray inside the cavities with Waxoyl or something. I have heard rumors that it's often cold and damp up there.

I'm not so sure anymore, initially I was thinking breaking the rigid insulation into small pieces maybe 2"x2" or smaller, and I filling the void until they're stuck in there and they can't move. but if I do that I wont be able to pour it on the bottom... the mixed liquid is going to hit all those pieces while going down and probably won't make it to the bottom, leaving some air space here and there...
Maybe I could insert some pieces manually from the top after pouring the liquid?

Yes I have done a lot of research on this product, I will use closed cell so water or humidity absorption. My van has been sitting in my heated garage for a while now, it's completely dry, and the foam will create a vapor barrier, to prevent moisture coming in.
Read the description on this page.
Urethane Foam , Expanding Marine Polyurethane Foam

[Jsweezy]

Originally Posted by JWA

Hoping you'll pay close attention here.........general observations.....

Cavities before the mid line of the standard E-Series van can be filled with bat-type fiberglass insulation. Not stuffed in, just laid in to act as its intended to do. I've done this but keep it no lower in the cavity than the level of the factory floor.

Plywood over the floor is better since it leaves small channels for air circulation. One huge problem with cargo-only vans that leave the OEM padded mats in place is the padding absorbs humidity, eventually becoming saturated and causing rust to form completely out of sight.

The plywood is more than enough insulation since heat rises anyway and if using 3/4" it kills road noises unbelievably well.

Not to hijack but I had a question that I am sure others will be wondering.

How do you fill the cavities without going below the level of the factory floor? I was debating on filling the cavities with the fiberglass but didnt want it to get into the bottom and soak up moisture, and then I saw that you have done it without having it get into the bottom and was wondering how.

I also agree that the OEM Mats hold way too much moisture for a floor. I have thrown the "Stall mats" in my van instead of the Plywood (both are 3/4") and have found similar results as explained above. It is rigid enough to leave the channels open, helps immensely with road noise, great insulator, easy to clean and is comfortable to sit on. Just wanted to share.

[evy]

Originally Posted by JWA

Hoping you'll pay close attention here.........general observations.....

Any form of spray insulation UNLESS specifically formulated for automotive use, especially in eventually concealed areas behind interior trim should BE AVOIDED! In your case Evy the upper fiberglass cap can/will easily accommodate the spray in foam as it won't react detrimentally with that material as it would against body sheet metal.

Cavities before the mid line of the standard E-Series van can be filled with bat-type fiberglass insulation. Not stuffed in, just laid in to act as its intended to do. I've done this but keep it no lower in the cavity than the level of the factory floor.

I've used a foil, bubble wrap and PVC sheet sandwich radiant barrier insulation applied directly to the inside sheet metal. In your case this could be used over the fiberglass insulation filled cavities, no real need or huge benefit to covering the wheel wells assuming those will be covered with seating or a bed of some sort.

Plywood over the floor is better since it leaves small channels for air circulation. One huge problem with cargo-only vans that leave the OEM padded mats in place is the padding absorbs humidity, eventually becoming saturated and causing rust to form completely out of sight.

The plywood is more than enough insulation since heat rises anyway and if using 3/4" it kills road noises unbelievably well.

As a matter of general opinion ANY material not specifically automotive related is a huge no no. The Sika product would NOT be a good choice regardless how carefully you plan on applying it---its not intended to use used for your intended use. Because of this the longer terms effect of this product used contrary to its intended use is unknown, not really worth the risk of it causing damage to the body even if it's expansion can be controlled.

I hope you consider this seriously before going forward---its not something I'd feel comfortable with knowing there are too many potential downsides using the wrong materials.

I have done my research on this product.

Here's what I learned = Polyurethane is polyurethane.
It's a general use product, it can ben poured or sprayed, it's always the same = two parts that you mix up together and when exposed to air it will expand.
Closed cel polyurethane can be used for :
Insulating basements, walls and ceilings.
For boyancy in boats.
impact protection (hard density)
Hey I've seen it used to raise concrete slabs by injecting it underneath and using the expansion to raise the slab.

Please take two minutes to read the information on this page
Urethane Foam , Expanding Marine Polyurethane Foam
It explains the difference in density vs usage, very informative.

But tell me JWA your post is base on you personal opinion or by actual experience? Do you know something I don't? and maybe I should know?

[1der]

Not sure if it is the "best" but I have chosen to use the "between inner and outer wall cavity" as its own insulation by keeping the air in that cavity some what "still". I did not want anything in the cavity to compromise the weep holes that allow the condensate to find its way out of that cavity. With even an insulated pop top we are going to be insulation challenged.

There is way more condensation in our rigs than most people really think. The water vapor from our breath, cooking, humidity, wet clothes, and,in your case, a shower(?) all makes for a reason to make sure the water that condenses to liquid is able to evaporate or weep out.

Windows are the number one area to get insulated. Your cabinets will provide a lot of insulating properties on their own. They also can be lined at the back with insulating materials.

IMHO, thermal breaks are important and is what I have concentrated on creating. It has worked pretty well, so far, down to zero F. Below -10? Well, that I do not know, yet.

[evy]

Originally Posted by JWA

Hoping you'll pay close attention here.........general observations.....

Cavities before the mid line of the standard E-Series van can be filled with bat-type fiberglass insulation. Not stuffed in, just laid in to act as its intended to do. I've done this but keep it no lower in the cavity than the level of the factory floor.

I've used a foil, bubble wrap and PVC sheet sandwich radiant barrier insulation applied directly to the inside sheet metal. In your case this could be used over the fiberglass insulation filled cavities, no real need or huge benefit to covering the wheel wells assuming those will be covered with seating or a bed of some sort.

Plywood over the floor is better since it leaves small channels for air circulation. One huge problem with cargo-only vans that leave the OEM padded mats in place is the padding absorbs humidity, eventually becoming saturated and causing rust to form completely out of sight.

The plywood is more than enough insulation since heat rises anyway and if using 3/4" it kills road noises unbelievably well.

I am aware of the condensation issue under the OEM mat.
So I did this :





The floor is completely water proof now.

I re-installed the OEM mat, added a 1" rigid insulating board on top and by bolting a plywood board to the floor I eliminated any void in between, eliminating the possibility of condensation, air moisture cannot condensate if there are no voids.



But I didn't do this out of experience, this is my first build, whatever I'm doing, It is based on a lot of research on forums, googling the internet and personal opinion/knowledge, with that being said I could still be wrong and way off the track, but I sure hope not...