insulation question

[m725]

So I just got done gutting the back of a m725(68 military ambulance).  In the pic is the back I did take out the old insulation it was moldy. fixed some water leaks now I need to reinsulate the sides and the floor. I have an 1.5 inches to insulate.  I am thinking on using rockwool from lowes . the reason why I want to use it. Has anyone used this stuff

• Excellent sound absorbency
  
• Non-combustible, fire-resistant up to 2150 F
  
• Easier and faster to install
  
• Water-resistant
  
• Made from natural and recycled materials - user friendly, no fiberglass in product
  
• Better fit, flexible edge compensates for normal frame variability, cuts easily
  
• GREENGUARD certified; chemically inert - CFC and HCFC free product and process
  
• Does not promote growth of fungi or mildew
  
• Friction fit to ensure optimum performance, no sag over the years

 

[m725]

If the monitors want to post this in the miscellaneous thread that would be great

 

[rvwandering]

Welcome to the CRVL forums m725! I moved your post to the Insulation section. You may find some helpful information in some of the other threads in this section.

To help you learn the ins and outs of these forums, this "Tips, Tricks and Rules" post lists some helpful information to get you started.

Most of our rules boil down to two simple over-riding principles: 1) What you post should provide good information (like your introductory post), and 2) Any response to someone else's post should make them feel glad they are part of this forum community.

We look forward to hearing more from you.

 

[wayne49]

Hi, I did a search on "rockwool" in the forum.

Here are the two relevant posts from someone actually using rockwool.

https://vanlivingforum.com/showthread.php?tid=13295&pid=202009#pid202009

https://vanlivingforum.com/showthread.php?tid=13295&pid=144884#pid144884

User is "Willy"
https://vanlivingforum.com/member.php?action=profile&uid=1405

 

[bullfrog]

It is not water proof. It most likely vibrate and over time end up at the bottom of the wall. Condensation most likely will occur and get things wet.Foam panels tend to be the insulation of choice as nothing much affects them and you can just cover them with glue cloth and paint. If your wall panels are raw wood on the inside did you seal them?

 

[highdesertranger]

yep number 4 on your list says it all,

water resistant

you want water proof

oh yeah welcome to CRVL

highdesertranger

 

[m725]

thank you for answering my questions

 

[Camper]

I only use Polyiso board from Home Depot.... it has the best R-rating, and won't sag.

Lowe's should have it too.

 

[Reducto]

Quick note about polyiso - the R rating actually drops with temperature. XPS (pink/blue rigid foam) actually performs the same or slightly better in very cold weather. The difference is slight, however, so it's ok to use whatever is available locally. XPS is better for gluing together in irregular shapes. Just make sure you use a glue marked safe for foam such as Gorilla glue. Polyiso doesn't squeak as much if it's a little loose and seems a bit more rigid due to the film bonded to the outside.

 

[BelgianPup]

Rockwool is made from stone. It does not absorb moisture, it is water-repellent. It breathes, won't trap moisture, and resists mold. People who have used it in vehicles say it does not sag.

 

[bullfrog]

Water resistant is not waterproof. Anything without structure hung on a wall in a vehicle gets severely vibrated going down the road. Most of these products are made to insulate stationary dwellings not made to withstand years of vibration going down the road. If it has been tested and approved by the manufacture for your use get it in writing. It is your time and money and therefore your judgment call as to what you use. These are only our opinions, let us know how it works out for you.

 

[BelgianPup]

My error... I skipped a couple of words.

I meant to type "waterproof and fire resistant"

 

[highdesertranger]

the wool itself might be waterproof, however it holds onto water the same way fiberglass insulation does. you also do not want to breath the fibers. highdesertranger

 

[VanFocused]

I used rock wool on my build but only in the ribs of the van... places where I could stuff the insulation down into nice and tight so it wouldn’t shift with vibration. Rock wool is water resistant but moisture permeable, if I remember correctly. This basically means it won’t collect and absorb moisture in the air like some other insulation (denim for example) but it can still allow the moisture to pass through so it won’t create a mositure barrier either. That can be beneficial if you have good airflow but it can also be bad because it can allow moisture to pool in areas as well. In my eyes I view rock wool as moisture neutral. It’s not the best for dealing with it but it’s definitely not the worst. I think ventilation is the most important thing in preventing moisture problems.

For the flat walls and panels I used poly iso foam boards and I did a bit of spray foam here and there as well. 

You might find this article helpful along with the ones other people posted. 

https://vanfocused.com/vanlife-stealth-camping/

Good luck on whatever you decide to do.

 

[PlethoraOfGuns]

I plan on using rockwool in my step van build. My ceiling is already fiberglass insulation, and I'm just going to leave that and install a layer of 1" foam board over that. But the walls I have are framed with 3" aluminum studs. In order to fill all that with foam board was going to cost a fortune. Rockwool seems like an easier, cost-effective alternative, while having all the advantages over the fiberglass. And I basically have the interior wall stud space like that of inside a house, so it will go right in unmodified. My hopes that sticking 3.5" rockwool into a 3" wall will help prevent any sagging over time. We'll see what happens...

 

[highdesertranger]

once you start crushing the insulation it starts losing it's R value. it's best not to crush it. how much are you paying for ridged insulation? highdesertranger

 

[PlethoraOfGuns]

Yes, compressing is bad. The 1/2" shouldn't be an issue. I think I will still have way good insulation as it's rating is R15. I just have lots of stud space to fill. Original plan was to do layer of 2" and then layer of 1" back to back to fill the wall space. 2" Polyiso is about $40/sheet 1" Polyiso is about $24/sheet. It comes to about $700, give or take, to do the whole van in Polyiso. Been looking for used stuff but haven't had much luck. Rockwool isn't cheap either, but I always see it cheap when builders buy too much of it. Either which way I go will be a ridiculous amount of R value. Most people don't do 3" of foam insulation in their rigs, haha.

 

[highdesertranger]

wow around here 1" polyiso is about 15 bucks a sheet. where are you? highdesertranger

edit: actually it's gone up slightly since last year,
https://www.lowes.com/pd/Johns-Manv...olyisocyanurate-Foam-Board-Insulation/3851111

 

[PlethoraOfGuns]

Yea, all construction material has gone up since the pandemic. A wood 2x4 is like $6 now!

 

[66788]

Yes, compressing is bad. The 1/2" shouldn't be an issue. I think I will still have way good insulation as it's rating is R15. I just have lots of stud space to fill. Original plan was to do layer of 2" and then layer of 1" back to back to fill the wall space. 2" Polyiso is about $40/sheet 1" Polyiso is about $24/sheet. It comes to about $700, give or take, to do the whole van in Polyiso. Been looking for used stuff but haven't had much luck. Rockwool isn't cheap either, but I always see it cheap when builders buy too much of it. Either which way I go will be a ridiculous amount of R value. Most people don't do 3" of foam insulation in their rigs, haha.

I did 2 inches on all 6 sides in my step van build, along with dual pane windows.  Super good results, I use about 1 pound of propane or less each night in 26 degree weather.   Been down to low single digits with ease.

As for AC, my Frigidaire 5K window unit runs well with my Honda EU1000i and cools down to 68 on a hot day on low setting.

Good insulation is a wise investment for both heating and cooling.