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Full Version: Thinking of adding a ***gigaton*** of Insulation... is it worthwhile?
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One of the things I am going to focus on the most with my van build (might happen in the Spring... if I can hold out that long) is insulation. Insulation will not only be important for warmth, but also as a sound barrier.

The question is can one take it too far?... to the point of diminishing returns? I live in the pacific northwest and I am a wuss when it comes to cold. I'm also cheap in that I want the heating costs to be as low as possible. Also, while I accept that I will have to tolerate a certain level of noise (I have to urban stealth in my situation) I want to do as much as I can to minimize that noise. I don't mind spending the money on a giggatone of insulation if there will be signifcant improvements over moderate insulation. The only other drawback I can see is that it will eat a bit more space, but that's okay with me. One of the main reasons, after much thought, I decided not to go the mini van/astro route is because I want to go overkill on the insulation and those mini vans are just too small to afford the space. By overkill I mean 4 to 6 inches of just the foam board. I am thinking of even extending the depths of the van 'ribs' so as to add more foamboard... IF its going to definitely be benenficial to add another 2 inches of thickness to the insulation. Thoughts on that?

Another related question is... (keeping the above points in mind) how thick should I go with for the wall panels? I was at Home Depot today and saw I could go anywhere from 1/8 to 1/4 to 1/2 inch plywood or "hardboard". I know the 1/2 inch won't bend that well but I am okay with that... IF its a noticeable improvement in noise reduction and heat retention. I could do two 1/4 panels layered which would bend easier and still end up with 1/2 inch. I should note that I intend to build a wall over the rear doors and I might build a wall over the sliding door and incorporate a second door into that wall and keep it closed over the winter. I'd probably just leave that door in the open position for most of the year. The point is I am going to build this thing air tight. For ventilation I will have both an intake hole and an outake hole (the second with a 5 inch computer fan to draw out the humidity and keep good air circulation.

So to summarize... Tongue

1. What is the maximum thickness I should go with the wall panels... 1/2 inch? I should also note that being a cheapo I'm also trying to keep the weight down of stuff that I build so I'd rather not go over 1/2 inch. The lighter I can keep the van build the less I will have to spend on gas.

2. Is 6 inches of rigid foam board just ridiculous overkill versus 4 inches or will there be a significant difference in noise reduction and heat retention?

Thanks for your ideas, thoughts and opinions. ?☺Smile
For sound blocking ideas, consider checking out loess's build here.

My understanding is that, while it's a bit of an oversimplification, mass deadens sound. So anything that truly makes much difference in reducing noise will be heavy. Most insulation is lightweight and geared towards trapping air, which I would not expect to make much difference in noise.

I'm also in the PNW and quite sensitive to cold and noise. Very interested to hear what others advise on the subject.
Rather than (or in addition to) putting foam between the ribs I'd want to cover the entire surface. I did that with a thin layer and got good results. I don't even have wall panels, just the 1/8" blue foam. I thought I'd test it for a while to see if it held up and it's been good so far, so at some point I plan on gluing fabric over it. Maybe run a couple of lengths of wood at different spots so you have something to screw things into and have foam boards above and below it.

1/2" wood panels everywhere would be HEAVY. I'd suggest going as thin as you feel will hold up. The 1/8" hardboard I used on my ceiling is a little bowed but otherwise fine. 1/8" plywood would be stiffer. Wood is not a very good insulator anyway - you're really only using it to protect the foam and to attach things to.

2" sounds like plenty to me - I'm not sure where you'd actually hit overkill but the only downsides are cost and eating into your space. If you want more, go for it. Just make sure you maintain two exits - I've had my side door not open because I accidentally hit the child safety switch. You could be blocked for other reasons as well.
It also depends on where you will spend the majority of your time during extreme weather - cold or hot. Having a van you can move to better climates, negating such extreme levels of insulation. Of course work or family concerns may limit your ability to travel.
You might want to look into getting 4'x8' coroplast paneling for your walls. It's extremely light, non-porous, and easy to instal. ..Willy.
Also have you considered spray foam insulation. I have a step van that I prices out for putting in poly ISO boards versus the 2 part spray foam. Although the spray was more money it seems like it does a better job getting all the books and crannies that steal heat. Like to see how you do with this!
One of the vans I looked at was a sprinter that had been outfitted to carry frozen food. As I recall the walls/floor/ceiling were all about 4 inches thick. I think you need to worry more about covering everything, including the wheel wells, floor, ceiling, windows, than having lots of thickness.

Cdiggy, did you use the spray foam? I've been researching spray foam for some time now and haven't found a lot of people who used it successfully. I've read that after time it will come loose from the walls and squeak. I also read that it is corrosive. It seems like a good idea, but one has to wonder. My thinking now is to not put anything on the walls that will hinder looking at them to inspect for rust.
You can look at my build for ideas if you like.
I think if you go too crazy with insulation you'll lose a lot on space, something you'll probably regret sooner rather than later.
You can use Reflectix in conjunction with Polyisio, just make sure you have an air gap between it and the metal skin.
Also from my understanding the PNW is very humid with lots of rain. If I were you I'd make sure not to put anything in the van that can attract and/or retain moisture.
Also a roof vent should be a must.
The typical stick-built house has R-14 walls and in cold country they recommend R-36 roofs. You don't need any more than a house and you can afford to give up the room much less.

Polyiso is R-6 per inch so I wouldn't recommend any more than 2 inches in the wall and 4 inches on the roof. I think I wouldn't want to give up the headroom so I would only put 3 inches on the roof at most.

Bob
(11-25-2014, 03:22 PM)HarmonicaBruce Wrote: [ -> ]Cdiggy, did you use the spray foam? I've been researching spray foam for some time now and haven't found a lot of people who used it successfully. I've read that after time it will come loose from the walls and squeak. I also read that it is corrosive. It seems like a good idea, but one has to wonder. My thinking now is to not put anything on the walls that will hinder looking at them to inspect for rust.

I have not used the spray foam , I have only seen it used on you tube videos. I had not heard any of the horror stories from using it other then spraying when it was cold. As far as corrosive I have not heard about that either. It is supposed to be fully cured and inert in an hour but what it does in that hour is beyond me. Also my application is going to be an aluminum bodied step van so I was not real concerned with corrosion. I would use board but I have a lot of structure to go around plus 4 back windows and 6 side windows and it really does get drafty. Here I thought spray foam was the way to go!
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