Help Interpret this Response from the Rockwool People

[richard5933]

Originally Posted by Jcondon

I generally buy wrecks I make a new frame from all new material. Take it in to get it hot dipped galvanized. Then I install new Dexter galvanized axles. Then hot water radiant heat panels. Then a Coosa subfloor with epoxy too coat, then from fiberglass/aluminum composite ribs, all new channel and bows, and new outer skin for the straight sections. Then water cooled HVAC and a stainless steel wet bath. Commercial quality electrical components are next. So the slight added cost for an insulation that meets and exceeds all of the requirements of a quality build is insignificant.

What you're doing looks nice. If you're basically building from scratch with a new frame you can accommodate quite a bit, but I think you'd agree that it's way outside what most are doing. The average Airstream trailer has not got much headroom with regard to weight, especially once you start adding up all the modern gadgets and electronics that most have on their wish list.

[Jcondon]

My point is the builder is going to spend a lot anyway. Whether it is in the foundation or in the interior. Choosing a insulation method that punches all of the buttons adds very little to the overall cost of a build. Because building these right is expensive. If they have stripped the interior, replaced the subfloor and they are ready to insulate they are in pretty deep already. A few extra pounds distributed evenly around the entire shell will make no difference.

[richard5933]

Originally Posted by Jcondon

My point is the builder is going to spend a lot anyway. Whether it is in the foundation or in the interior. Choosing a insulation method that punches all of the buttons adds very little to the overall cost of a build. Because building these right is expensive. If they have stripped the interior, replaced the subfloor and they are ready to insulate they are in pretty deep already. A few extra pounds distributed evenly around the entire shell will make no difference.

Maybe.

When moving from my vintage coach to my vintage Airstream, one of the things that constantly hits me in the face is weight. In the coach we were near 30,000 lbs. A few hundred here or there didn't matter at all.

On the Airstream, like many, when we are loaded for a long trip we are often near the GVWR for the trailer. We evaluate everything we add to the trailer for many things, including how much it weighs. Some are trying to keep their builds below a particular weight so they can pull it behind their tow vehicle. Some because of the axle limits. Etc. Etc.

Insulation choices are important, but not everyone is trying to build a 4-season trailer. The extra weight we're talking about here is not just a few pounds - it can potentially be a few hundred pounds, depending on the length of the trailer. Adding that much extra weight in the insulation means taking it away from something else. For some, the extras that come with this type of insulation is worth the cost in weight. For others, not so much. It wouldn't be for us.

Whether or not this is the 'best' insulation is going to depend on a person's priorities in all these things. Not sure it's possible to make a blanket statement about which is 'best'.

[Jcondon]

Originally Posted by richard5933

Maybe.

When moving from my vintage coach to my vintage Airstream, one of the things that constantly hits me in the face is weight. In the coach we were near 30,000 lbs. A few hundred here or there didn't matter at all.

On the Airstream, like many, when we are loaded for a long trip we are often near the GVWR for the trailer. We evaluate everything we add to the trailer for many things, including how much it weighs. Some are trying to keep their builds below a particular weight so they can pull it behind their tow vehicle. Some because of the axle limits. Etc. Etc.

Insulation choices are important, but not everyone is trying to build a 4-season trailer. The extra weight we're talking about here is not just a few pounds - it can potentially be a few hundred pounds, depending on the length of the trailer. Adding that much extra weight in the insulation means taking it away from something else. For some, the extras that come with this type of insulation is worth the cost in weight. For others, not so much. It wouldn't be for us.

Whether or not this is the 'best' insulation is going to depend on a person's priorities in all these things. Not sure it's possible to make a blanket statement about which is 'best'.

I give up with y’all. I’m tired of justifying my position on everything I post. You drove me away three years ago with this same BS and you have done it again now. I have lots of educational videos to share but can not post. Signing out forever.

[Gene]

Originally Posted by Jcondon

I give up with y’all. I’m tired of justifying my position on everything I post. You drove me away three years ago with this same BS and you have done it again now. I have lots of educational videos to share but can not post. Signing out forever.

Another person finds the internet is not for the sensitive.

[Ray Eklund]

Originally Posted by Jcondon

I give up with y’all. I’m tired of justifying my position on everything I post. You drove me away three years ago with this same BS and you have done it again now. I have lots of educational videos to share but can not post. Signing out forever.

*****

Keep doing what you do. We all learn something when two or more active restorers toss out some curve balls. Then a knuckle ball confuses everyone.

I am among the Silent Majority in Airstream restoration projects, as l like a smaller scale project like a Wurtlitzer Jukebox or a Mills Slot Machine.

Hang in there... my wife tells me to find something more interesting to do. So I bought an Oliver Elite II. Have not made ONE POST on the Oliver Website since owning one. A well designed and thought out travel trailer. Some may want to argue the point, but I have owned Airstreams since 2006 and an Oliver for a year.

Experience is earned by doing and experimenting with new and old materials.

Many individuals have taken different routes to get here from the beginning. No reason to defend your reasoning. There are lots of ways to secure the interior of an Airstream... Pop Rivets or Lath Screws (my choice).

I do not mind at all if anyone does not agree with me... as I let them make the same mistakes over and over.

Looking forward for you to stick around and let the readers decide.

[pcskier]

Originally Posted by Jcondon

I give up with y’all. I’m tired of justifying my position on everything I post. You drove me away three years ago with this same BS and you have done it again now. I have lots of educational videos to share but can not post. Signing out forever.

If anybody disagrees with you, it’s BS?

Don’t forget to take your ball with you as you leave the sandbox and go home. Too bad though as you certainly have great knowledge to share as far as I can tell.

[Vernation]

I personally come here specifically to hear differing perspectives--it helps me make better, more informed decisions.

My Rockwool research aside, weight is a strong consideration for my project. I have one axle and a 5" frame. I'm hoping to put less weight back in than what I took out, because there are other things I'd like to add (like solar) that I need the wiggle room for.

I weighed everything as I removed it towards this end. (Unfortunately I did not think to weigh the fiberglass--that would have been good information to have given this discussion).

You put your perspective out there. Some will agree with you, some won't. That's just the way of things. It doesn't mean that what you say has no value.

[Gene]

Something I forgot and was alluded to elsewhere, but perhaps not understandable by everyone. The ribs that the inner and outer skins are attached to, transmit lots of heat or cold from one side to the other. A thermal break is when you interrupt that pathway with something that is relatively nonconductive—a strip of rubber for example. I am sure there are other things that work better, but rubber is easy to understand. So if you take the inner skin off, before you put it back, you use rubber or something better, attach it to the ribs and go from there. I'd rather have it under the exterior skin, but I think this was about the inside.

I'm just an amateur who reads and remodels every house I've owned, but the principles are pretty much the same for RV's. How to do this stuff has changed radically in the last 30 years, and I am past my sell by date.

[Vernation]

I found this article:

https://buildex.techinfus.com/en/ute...a-ves-1m3.html

It has some brand names that I haven't heard of and it has prices in rubles, but it also talks about weights and densities of various insulation media.

Seems like perhaps different rock wool products can vary in weight.
If I read it correctly, it talks about how density is a trade-off because the denser the material, the heavier it is. But also more density can equal more heat conductance?

It includes this table, which I found interesting:


Name kg / m³
Cellulose wool 30-70
Fiberboard 150-230
Linen mats 30
Foam glass 100-150
Cotton wool 25-30
Mineral wool 50-200
Styrofoam 25-35
Extrusion expanded polystyrene 35-40
Polyurethane foam 30-80
Expanded clay 450-1200

[richard5933]

If my understanding is correct, the denser insulation is often used as a sound insulation. For temperature insulation a vacuum works well and weighs nothing - not really well suited for this application, but does show that density and weight is not necessary to get a thermal barrier.

[hairyclive]

Originally Posted by foobar

If it has copper in it, then it is not a good idea to put it in contact with aluminum.

Aluminum and copper plus moisture = galvanic corrosion, with aluminum representing the sacrificial metal that gets damaged or destroyed.

I don't know if rock wool has copper in it or not. If it does, it is not a good idea to use it in contact with aluminum.

If you are skeptical, just Google search copper plus aluminum ships/sailboats. I have seen aluminum hulled sailboats sink because someone dropped copper coins in the bilge and the aluminum hull was destroyed in the area that was in contact with the coins. The degradation only took a few weeks or months depending on the ambient temperature and then bye bye boat. Of course, this process will take longer in the Airstream because moisture is not continuously present.

Mineral insulation can contain a number of metals, steel, magnesium, basalt rock and other materials depending on type and manuf.

https://inspectapedia.com/insulation...omposition.php

Rockwool makes a product for metal buildings, if that is compatible with aluminium it could be a good choice

https://www.rockwool.com/north-ameri...ll-insulation/

Advantages of mineral insulation is it is almost fireproof, waterproof, and very good at sound deadening.

https://www.rockwool.com/north-ameri...ning/firesafe/

some interesting information in the side comments on this table

https://inspectapedia.com/insulation...lues-Table.php

[Kayode]

We used that same Rockwool product (2") as the top layer of a floor insulation followed by high density foam and it works amazing for the reasons hairyclive mentioned.

But, I wouldn't recommend it for the walls. The stuff is pretty dense and has the consistency of semi-rigid cardboard so insulating around curves may be an issue.

We used polyarmor for insulating our walls and its definitely easier to work with and better than the pink stuff. https://ductmate.com/product/polyarm...er-duct-liner/

But like most things, it ain't cheap

[Vernation]

I was reviewing some older posts for forgotten pearls of wisdom...


Kayode,
Stupid question for you about the insulation:
Silver liner towards the inside, or towards the outside?


Also, are you still satisfied with your choice?