Acoustic and Thermo Insulation (duel purpose)

[7wanders]

in the next few days I'll be buying an empty, all aluminum step van for conversion. the step van runs on a cummins 5.9 diesel which is very loud in the empty aluminum interior. I test drove a few step vans that were decked out tool trucks with commercial insulation and they were about as quiet as a dodge diesel which is a far cry and huge decrease in noise over the empty aluminum box

so, my goal is two fold, I want to drastically reduce the acoustic noise of the diesel while also doing the normal thermo insulation. 

I realize Bob recommends not insulating the floor because most van dwellers run without AC (cold air goes down and tries to penetrate the floor) and recommends focusing the thicker thermo insulation on the ceiling to try to keep hot air from getting out as it rises. 

I'm looking for a happy combo of the thicker ceiling insulation, medium walls, but feel something is necessary on the floor given you have a gigantic aluminum reverberating conduit for road noise, transmission, drive train and engine. 

oh, and I'd prefer to be environment friendly both in terms of avoiding toxic stuff in the living space (off gassing etc) and trying to be as green as possible. salvaged or pre-owned materials preferred

at this time I'm considering something like a layer sandwich:
1. bottom layer being a synthetic vapor barrier combined with something to reduce acoustic vibration (maybe a variation of the product "Grace Ice & Shield")
2. layer of pink solid foam for both minimal R value and acoustic reduction
3. layer of marine grade plywood
4. traditional wood plank flooring (whatever reclaimed wood I can find)

I'd really like some help troubleshooting this equation including focus on reducing the acoustic noise from the diesel coming up through the aluminum box.

thanks in advance!

 

[Every Road Leads Home]

It's not the cheapest option in the world, but dynamat does a really good job at stopping road noise. For the ultimate combo, I think i'd do a combo of this on the Floor, walls, and ceiling. And then spray foam the walls and ceiling. Followed by your plywood and finished flooring and you should have a considerably more quiet ride.

https://www.summitracing.com/search...cm_mmc=ppc-google-_-search-_-brands-_-keyword

 

[7wanders]

thanks for your advice. I'll look into the dynamat. I'd rather not go with spray foam (read a lot of posts about avoiding it in small mobile living spaces, but seems like people are divided on that one)

 

[DannyB1954]

3M Thinsulate is touted as also being a sound dampener. I don't know about using it on a floor as it may compress. Maybe something like this would work, https://www.amazon.com/gp/product/B...fl_title_18?ie=UTF8&psc=1&smid=A33WZPZ4QHXNRF Using different layers of materials with different densities will reduce a greater spectrum of noise. Ever see those generators that look like shipping containers, (maybe at a fair or amusement park)? You can hardly hear the diesel inside screaming, that is one method they use to do it.

 

[CautionToTheWind]

RattleTrap Sound Deadener -- I've seen this used full coverage however not needed as it's overkill (per the manufacture). Perhaps use more percent closest to the engine/floor-front area.

 

[karl]

I used a commercial carpet that has a 1 1/2" thick high density foam back on my floor, then covered it with ply/laminate. I don't have a link, but the stuff is used in gyms, play areas, etc. It reminds me of sound booth egg crate foam in color and density.
Also used Dynamat or similar to line the doghouse, firewall and foot space, door skins, etc.
The walls and ceiling are 1" foilfaced foam with cloth glued over it and painted
Curtains are appliance blankets
Anything that doesn't conduct or reflect sound helps.
I am considering spray foaming the under floor in areas that are not subject to heat from exhaust as well

 

[Bud Smiley]

I like horse stall mats or other heavy rubber mats. They provide good acoustic insulation and are decent for heat as well. I like the feel of them under foot. They are easy to remove and clean. You might get some off gassing initially if you buy them new.

Congrats on the step van.

 

[Every Road Leads Home]

thanks for your advice. I'll look into the dynamat. I'd rather not go with spray foam (read a lot of posts about avoiding it in small mobile living spaces, but seems like people are divided on that one)

Just my personal experience with the spray foam.  I had my entire house sprayed with it and they finished at 4pm.  I set up my recliner and tv and watched Tv in the room a few hours later.  Watched Tv in there everyday for a few weeks until I got around to doing the drywall. Never got so much as a headache.  After a few days the little smell that it had right after the installation was all but gone.  I know there's a lot of horror stories about it online though and I had considered those when I decided to go with it.  Seems most issues with it are lack of improper install more so than the actual product.  But I can certainly understand why someone would chose not to use it and can respect that.  As far as sound and insulating qualities, it's excellent.  

One more thing you could do is blown in cellulose, which is pretty eco friendly.  The guy that did my insulation said it's actually much better at reducing noise than foam.  I wanted to use that, but they couldn't go it for another month and winter was closing in on me quick.  My one reservation on using this method in a van would be i'm not sure if or how much it would settle with the constant vibration of the vehicle traveling down the road.  

Glad you started this thread though, as i'm constantly thinking of how i'll insulate my build when the time comes.  I'm leaning towards spray foam with my positive experience i've had with it in my house.  However, I do have in the back of my mind the possibility it may have some long term health effects not immediately noticeable.  But I suppose a lot of things do that, that we pay no attention too.  

There's always the tried and true method of using Polyiso, which seems to be the preferred method in most my research.

 

[LeeRevell]

I like horse stall mats or other heavy rubber mats. They provide good acoustic insulation and are decent for heat as well. I like the feel of them under foot. They are easy to remove and clean. You might get some off gassing initially if you buy them new.

Congrats on the step van.

Have been considering this myself. Tractor Supply Store is just a few miles from me, and the price is good.

 

[highdesertranger]

I don't know where you guys are getting rubber mats but the ones we had for our stock trailer took 2 people to pull them out and reinstall when we washed the trailer. those things were damn heavy and awkward. highdesertranger

 

[ArtW]

the ones from Tractor supply are 4x6, 3/4 inch, they weight 45lb and they can be rolled, though with some difficulty
They smell of rubber pretty strongly
OTOH, you can drop a 500+lb barbell on them over cement with iron plates and not damage the floor, mat, or weights
and they do feel pretty good underfoot

 

[DannyB1954]

I would be concerned about off gassing. I replaced all my tires about 6 months ago. When I got close to the spare the other day, I could still smell it. (it has been on the back door hanging in the sun and wind). Most horse trailers have lots of ventilation, a van, not as much.

 

[Vanada]

Some good sound deadening plus Thinsulate might be what you want. It is synthetic but I haven't been able to smell anything so can't really say about off-gassing. Can confirm that it would be useless on the floor unless you build a framework to support the floor so that it could sit in between without getting crushed. Polyiso or XPS board insulation would be better for the floor.

This is a really great writeup on soundproofing:
http://vandogtraveller.com/how-to-soundproof-a-van/