Floor insulation? Material?

[cuyeda]

What type of floor insulation is used?

After lifting the entire sub-floor out, exposing the belly pan, there was very little original fiberglass insulation. After reading another thread, someone used a double sided foil material. This is not my trailer, someone elses picture for reference.



This looks like a great idea, but wonder if this is overkill or a great idea? I was thinking of adding the regular insulation over the top to fill the air space.

What do others think?

[boatdoc]

Hi cueda; Insulating the floor with a double faced foil insulation such as Prodex or Reflectix is definitely not a overkill. This insulation averages above 14.0 R value and is even more effective when you provide air barrier on each side. There are many threads on insulating the AS including one by me titled "Quest for a new Stainless steel Frame" if you use search forum. Thanks, "Boatdoc"

[Chuck]

Originally Posted by boatdoc

... This insulation averages above 14.0 R value and is even more effective when you provide air barrier on each side.

wow. where'd you get that number? I didn't think they even claimed that much on the label...
(I don't doubt you; just wonderin').

[LI Pets]

Not overkill, cheap about 25 cents a square.

JUST do it that way you'll love it.

I saw R-14 also.

[Janets Husband]

Bubble seems to be the way to go. I will be using it in the walls and floor.
Try this site for further info. Insulation 4 LESS They claim R 14.1 with the proper Air Spacing.

[boatdoc]

Originally Posted by Chuck

wow. where'd you get that number? I didn't think they even claimed that much on the label...
(I don't doubt you; just wonderin').

Hi Chuck; I think LIpets just second my statement. Thanks, "Boatdoc"

[cuyeda]

I wonder if the bubble foil insulation at Home Depot or Lowes, has similar "R" values. Othewise, I will be revisiting the "insulation 4 less" referral.

Thanks for the input and vote of encouragements.

[Foureagles]

The stuff at Lowes is Reflectix. Note that advertized R-values (anywhere from R-3 to R-14.6) are for whole assemblies with very specific construction details -- particularly air spaces and infiltration sealing. Reflectix itself measures R 1.04.

[Wabbiteer]

From Insulation4less web site:

R Values for single layer foil-bubble-foil
Heat flow down: 14.1
Heat flow up: 4.9
Heat flow horizontal: 6.2

So - for heating the interior the foil-bubble-foil insulation will yield the R-14 if applied as specified; for cooling the interior the heat flow will be 'up' and the foil-bubble-foil BEST CASE will be R-4.9. I've posted this before but R-14 keeps getting repeated for some reason.

For my floor-on belly rehab I used foil-foam-foil with a single sheet held off from flooring by a single layer (.25") 2" wide strip around periphery accessible floor (between the stringers & outriggers) and used two layers at center to provide some drainage if/when liquid moisture invades the area.

http://www.airforums.com/forums/307547-post26.html

[malconium]

I don't think that heat flow and R value ratings tell the whole story when it comes to reflective insulation. It is my understanding that the measure of heat flow has to do with heat transfer by conduction through the material being tested. While it is true that warm air rises to the top of an Airstream it is also true that a very large percentage of heat loss through the ceiling and walls is not by conduction or convection but by direct radiation. I don't recall the exact numbers at the moment but radiant heat loss through the ceiling is something greater than 90% of the actual total heat loss while it runs something in the high 80's through the walls. Relective foil insulation stops about 97% of the radiant energy transfer (according to the same rating chart at Insulation4Less). The direction that radiant energy is traveling depends on whether it is warmer outside the AS or inside. During the summer radiant energy is trying to get into the trailer while it is trying to get out during the winter.

Even if it were true that the maximum effective value of reflective foil was only a product of its R value it would still be as good as fiberglass insulation. Firberglass has an R value of something like 3 per inch which puts it at about R 4.5 for an airstream wall. Fiberglass, however, does nothing to stop the flow of energy by direct radiation. So my question is how could fiberglass of the same R value as reflective foil possibly be as good as the reflective foil? I have personally run tests on the amount of radiant energy that gets through various types of airstream wall insulation construction. Check out the following threads for information about my tests and lots of other discusssion about foil insulation:

http://www.airforums.com/forum...lts-13953.html
http://www.airforums.com/forum...red-13363.html
http://www.airforums.com/forum...cks-30196.html

Malcolm

[Wabbiteer]

The rule of thirds applies to heat flow: convective, conductive, and radiant each will try to transmit its equal share seeking equilibrium in non-exotic materials. Comparing fiberglass to a radiant barrier? Just look at paths of energy flow, and our lovely Aluminum shells and frames... there isn't good conduction from metal ceiling heat bubble through shell ribs-floor-axles-tires to ground so conduction is null, the aluminum offers no/low texture to increase surface area and make convection a major player so radiation of infra-red is dominant.

Comparing radiant barriers to fiberglass - note sharper temperature gradient per unit of distance; the heat that does push through the foil-bubble-foil will be more energetic compared to heat that has pushed slowly across greater distance of the fiberglass baffles; sort of like a minute hole in a high-pressure tank leaking the same as a larger hole in a low-pressure thank... Does that illuminate the subject in any different ways?

[malconium]

I saw a special on the History Channel last night about insulation. It did focus more on foam and fiberglass than it did on reflective types of insulation. It did mention, though, that insulation for space stations was entirely reflective. Evidently with no air in space there is no possibility of heat loss or gain by convection or conduction.

There was also mention of a type of insulation that I had not heard of before. The technology is called gas filled panel insulation. Check out the following sites for some information:

Gas Filled Panels
Technology Transfer
http://gfp.lbl.gov/papers/lbl-38093.pdf

I have not looked into this new type of insulation enough to find out if there are comercially available products that we could use for an Airstream. The claim though is that 1" of gas filled panel insulation can give the equivalent insulation value of 2" of foam.

Malcolm

[HiHoAgRV]

My system r-vaule would significantly improve if I could get the family to close the darn door.

[malconium]

Interestingly if your heating system produced direct radiant energy having the door open a lot would not matter nearly as much as it does with forced air heat. Think about the out door heaters that you may have seen and reflect on the fact that they are pretty much all radiant heating systems. Also, think about how nice the sunshine feels on a cold day even though the surrounding air might be pretty cold.

Malcolm

[boatdoc]

Originally Posted by Foureagles

The stuff at Lowes is Reflectix. Note that advertized R-values (anywhere from R-3 to R-14.6) are for whole assemblies with very specific construction details -- particularly air spaces and infiltration sealing. Reflectix itself measures R 1.04.

Hi All; Let us encapsulate the issue of insulation once and for all. It needs to be understood that any older AS with standard fiberglass insulation has many negative issues.
First of all, it sags and compacts leaving large open and un-insulated areas. It does retain moisture as good as a sponge, [best temp conductor]. Moisture barrier paper with time deteriorates, by exposure to heat. Fiberglass has a low R value to begin with. The fiberglass insulation in the walls of my 1973 Argosy was compacted by about 30%, while many sections had no insulation at all. Belly pan insulation held enough water to take a short shower.
Product such as Prodex and Reflectix, when properly installed offers the best results for the money. We can go on disputing each other about claimed R values but the fact remains, it is best we can do for the money in case of our application in AS. If anyone could call NASA and order the best in the world, we would not bother with bubble foil. What I am trying to point out is, that bubble foil insulation is perhaps the best we can do for the money, and until we can get a better product our arguments about R value numbers are of no concern.

If we decide to go through the trouble of re-insulating our AS, then proper procedure of installation should be observed in order not to waste our money and effort. I believe that everyone understands that bubble foil offers the best moisture barrier if the edges are sealed in, thus stopping possible air flow. Ribs should be faced with bubble foil as well to minimize heat transfer area through rib surfaces. Surface of bubble foil is many times more efficient in reflecting radiant heat over fiberglass insulation. Providing a airspace on both sides of the foil through use of 1/2" urethane foam strips as spacer further increases the R value. Perhaps it is not the best insulation available but it is by far the best choice for the money, therefore the arguments of stated R value differences from 4.9 to 14.0 are of no consequence for that reason. Thanks, "Boatdoc"

[markdoane]

Boatdoc,

Appreciate your input on this. I need to say that the insulation in my '59 is not nearly as bad as your's was. Maybe the factory took more care when mine was built. All of the insulation was intact and none of it was wet.

I do think that R-value of insulation has consequence. It is the only approved method we have for measuring the overall (radiative, convective and conductive) effectiveness of various insulation materials. Is R-value perfect? No. However, unless you analyze the individual u-values of all the components in a structure, it's the accepted method.

I choose to re-insulate my Tradewind with fiberglass. I considered using Reflectix, and decided that fiberglas was the way to go, for me.

What I'm saying is, I don't believe the claims made for reflective insulation methods apply when installed in a Airstream made of aluminum. Maybe it will work better in a painted Argosy, I don't know.

As far as making a blanket claim that Prodex is the "best" method, I will wait until someone does a well designed, side by side test.

[Chuck]

fiberglass also gives you a fair amount of sound insulation. I'm really glad I put it in the partition walls in my house. there are areas that don't have it, and it makes a very noticeable difference.

I wonder what its like to sleep in the AS on a rainy night, under a hollow ceiling. It can get pretty loud as it is...without any fiberglass in the space, I can only imagine it being like trying to sleep inside a snare drum.

I know a person that did their AS walls w/ a layer of rigid polyisocyanurate...it'll be interesting to see how that works out.

[malconium]

I did do some thermal testing on various types of insulation that gave me enough information to conclude that I wanted to insulate my airstream with reflective foil instead of fiberglass. Check out the following thread and especially post 59 and 82:

http://www.airforums.com/forums/f4/p...red-13363.html

It is true that I did not take into account anything relative to sound transfer issues. I did use Reflectix foil and, if I were going to do it again I might want to use the type that has a foam core instead of bubble pack core because it supposedly has better sound absorbtion qualities.

Malcolm

[pinkflamingoes]

So is the foil tape mentioned on the insulation4less site the same stuff you get at Home Depot? We have a ton of it at home and I'd hate to spend the money unnecessarily.

[malconium]

I would be very suprised if there would be enough difference to matter - if there is any difference.

Malcolm