Insulation JM Microlite EQ

[GrantV]

I know that this topic has already been done to death, but I couldn't find anyone using this type of insulation and was wondering if anyone had any thoughts. I know a lot of people like to use prodex, but prodex is expensive and from my understanding from my insulation guy is that it only gets the high R value from a 2x4 gap with plywood installed on both sides. So, when installed in a trailer, the R-value may only be around 5. I know traditional fiberglass is around 3-4 per inch and poly iso board is approximately double, but only sold in straight sheets, so may be hard to install. In the end, there is no replacement for finite thickness.

Anyways, the insulation guy recommended John Mansville Microlite EQ. It is basically a bubble wrap double sided reflectix insulation attached to either 1.5, 2, 2.5, or a 3 inch fiberglass batt. All that has to be done is stuff it in between the ribs. The guy said that they like to use it in hotter climates like Vegas and Phoenix because of the reflective barrier. It is a duct insulation, but they do use it on roofs and so forth as well.

It is about 100 dollars for a 4 ft x 100 ft roll, and I am thinking that this would be a lot easier, cheaper, and still provide a similar R-value no matter what I stuff in the void.

Any thoughts would be appreciated.

http://www.specjm.com/files/pdf/AHS-448.pdf

[Wabbiteer]

The is nothing bubble about that, PDF quote "It is supplied with an FSK (foil-scrim-kraft) vapor barrier" meaning aluminized mylar/fiberglass mesh/brown paper on one side only.

Pre-Airstream I nabbed a roll of something similar for free - wasted it on a enclosed room in the garage and a water-heater cover. JM is quality name 101%, only thing I'd double-check with the JM Sales Offices is if its non-reactive with aluminum, spec sheet states compatible with steel, sometimes the chemistry was never intended to mix.

Vapor barrier toward the conditioned air side is from insulation bible to best eliminate condensation, what does your insulation guy say? Mylar to the outside could shield the insulation from exterior water leaks and maybe the liners would act as inside vapor barrier?

- what would be really neat is if the foil could be held away from touching the inner liners to eliminate conduction heat flow over the 450+ sqft of shell and give a tiny reflective boost to the R-Values, even if its only by a 1/16 or 1/8". No clue how to do that, just saying....

One roll would do the ends and windows & up areas, below that board foam?

[Protagonist]

Originally Posted by GrantV

Anyways, the insulation guy recommended John Mansville Microlite EQ. It is basically a bubble wrap double sided reflectix insulation attached to either 1.5, 2, 2.5, or a 3 inch fiberglass batt. All that has to be done is stuff it in between the ribs.

Given the thinness of your walls, you're probably best off using the 1½ inch thickness. The less you compress fiberglass batts, the better they work; the insulation comes from the trapped air between the fibers, not from the glass fibers themselves.

[GrantV]

I am thinking that is the stuff that I am going to use. The reflective barrier should help with the direct sun, to some degree and the fiberglass should do the same. I probably won't see much past an R-6 value, but I can live with that. I am also going to be lining the walls with a reinforced fiberglass plastic sheet as opposed to a factory painted aluminum skin. When I bought the trailer, it was already stripped to the interior walls, so I bought basically an empty shell. The guy I bought it from stuffed home depot R-13 fiberglass that was super compressed and I thought he did a poor job, so I pulled it out, and found that he had not leak tested it, or even sealed a lot of the problem areas. A lot of the fiberglass was wet, and I bought the trailer in June in So Cal.

While I had the empty shell, I also had a paint-less dent repair man come out to see what he could do to the troubled areas, and he got a lot of the dents out. He only hit me up $250 for 3 cars and the trailer. He was here probably 6 or 7 hours though, so I thought he gave me a really good deal. Usually they charge an arm and a leg. Popped out the bigger dents and a lot of the rock dents.

Thanks for your thoughts on the insulation.

GV

[perryg114]

Use 1" of foam and then a layer of the bubble wrap of your choice. I don't like fiberglass. It does not have a real good R-value compared to foam board and it sucks up water and stinks and smells and holds water against the metal. The bubble wrap is probably going to help you the most in the ceiling.

Perry

[GrantV]

The bubble wrap is a reflective barrier, from what I have been told. The insulation JM Microlite has a reflective vapor barrier similar to the bubble wrap. So, it should do a similar thing as the bubble wrap and the fiberglass should fill in the cracks nicely, unlike poly iso board. I actually thought about doing something like bubble wrap or prodex and fiberglass, but it is really expensive. The thing is, if I use a bubble wrap and 1 in. poly iso at R-7 per in, there is not much of a net gain. My insulation guy says that it is more important to fill in the voids then to have a poor fit and insulation leaks.

He goes on to say that a 5% void nets a 50% loss in total insulating capacity. So if I have to cut the board to tip it in, and it doesn't fit right, it won't insulate well. That is where the fiberglass comes in. As for water, check for leaks and make sure everything is sealed, just like in a house. My insulation guy used to own an insulation company, but now is just a general contractor, similar to what I do.

[perryg114]

Small pockets of air are a good thing. Air is a poor conductor of heat as long as you don't have large areas where convection can take place. If you use foam you want to tape all seams with some silver duct tape. Air, foam board, air, foam board, bubble wrap is a poor heat conductor. Every thermal interface you have the more conduction you loose. If you have a void all the way through all layers, then you have a problem. These would be areas like speakers, wall sockets etc.

Perry

[Wabbiteer]

Hate to call foul - the interior metal sheet liners are a structural element...

[perryg114]

Who is said leave the interior skins off?

Perry

Originally Posted by Wabbiteer

Hate to call foul - the interior metal sheet liners are a structural element...

[jeg920]

I thought the reflective barrier needed to be near the outside to reflect the heat at the source (exterior skin). I was thinking of the following sequence: exterior skin, reflectix (with edges taped to frame sides), foam board (with edges taped to frame sides to close gaps), tyvek home wrap as an interior vapor barrier, then interior shell skins. Should provide heat reflection close to exterior source, moisture barrier on interior side, minimal places for water to adsorb, mold to grow.

Is this over the top?

[Protagonist]

Originally Posted by jeg920

I thought the reflective barrier needed to be near the outside to reflect the heat at the source (exterior skin). I was thinking of the following sequence: exterior skin, reflectix (with edges taped to frame sides), foam board (with edges taped to frame sides to close gaps), tyvek home wrap as an interior vapor barrier, then interior shell skins. Should provide heat reflection close to exterior source, moisture barrier on interior side, minimal places for water to adsorb, mold to grow.

Is this over the top?

You do realize that Reflectix is no more reflective than the aluminum skin of the trailer, right? The advantage to the Reflectix is all of the tiny bubbles, not the reflective surface. You're putting it in the walls to provide an air gap made up of bubbles that are too small for convection to occur. It would be different in a stick-and-brick house or in a fiberglass boat, where the reflective surface of the Reflectix is the most reflective surface in the wall.

If all you wanted was a reflective surface, you wouldn't need Reflectix, just shiny Mylar, like a space blanket.

But putting the Reflectix right behind the outer skin is good; that puts the air gap right behind the hottest surface, which will help the foam work more efficiently.

[GrantV]

I am going with the reflectix barrier close to the skin and 1.5" -2" foil backed insulation. On the new airstreams they still run fiberglass batting. Fiberglass is just simpler and easier. While the foam may have a higher R-value, it is harder to work with and requires lots of taping and cutting.

I have also been told that the major heat comes from the ribs through the outer skin to the inner skin. This is a major source of conduction, and can't really be compensated for unless a barrier is created on the ribs, as Aluminum is a pretty good heat conductor. They sell insulating strips you can lay down as well.

As for foam, if you really want to go the foam route, buy it in a 10-30 lb. cylinder. Tape up the reflectix barrier and spray it. When your done, you can cut away any excess. You can buy poly-iso pre mix in a cylinder and just lay down thin coats as it builds fast. A little hard to work with and a little hard to find, but check with your bigger insulation suppliers.

I am surprised no one has mentioned spraying foam. I wouldn't spray fiber or recycled newspaper, as the R-value is low but it is cheap. That is why they lay down thick layers for houses and so forth.

As for the interior skin being structural. I think it is only structural for the cabinets, and even those should be mounted to the ribs. I was probably going to run marine grade fiberglass reinforced plastic. Durable, scratch resistant, as strong as aluminum, and cheap. And in some areas, I was going to lay some veneer and finish it.

[vinstream]

A thermal break on the ribs to STOP heat transfer from the exterior to the interior is the most important insulation part of the entire system that is used. I use a 3m tape between the exterior ribs and the exterior skin as well as using it between the rib and the interior skin.

Despite all the negative chat about spray-in insulation, In my opinion made by many who don't know anything about it nor how it works, out preforms any other form of insulation in a 1-1/2" void period end of story! It also eliminates condensation in or on the walls-roof if installed properly. It also becomes a SIP panel when done correctly producing a superior end product. For the record I am not referring to spray foam cans purchased at big box chains.

The only negative thing about spray-in foam is when panels need to be repaired, and in those cases the correct way is to replace the entire panel and not cut corners and do patch work as stated by companies that state negative comments about spray foam and don't even use 2024 alclad nor buck rivet panels in place. Spray foam can be removed very simple with the right tools with out any chemicals.

The bubble rap with mylar may look cool but has very little return for the price and labor to instal. Fiberglass has more r value and is way less expensive. Both hold water, both do nothing to prevent condensation, both make cool nesting material for little friends.

One last point... The window glass is over looked by many and is the major point of heat loss but more importantly the largest source of heat gain. Spend your money on replacing your glass with a low-e coated glass and you will see and feel a greater differance than all the insulation mods you can come up with.

Good luck!

[jeg920]

After reading a good bit about Reflectix on their website it appears the material works best when it has a air gap between it and the space you are trying to keep heat from, up to an R-10 value. See here for metal roof building installations... Product: Reflective Both Sides | MB Roof - New

and it states
• Inhibits dew point condensation
• Vapor retarder (0.02 perms)
...
• Resists growth of fungi, mold and mildew
• Does not support insects or rodents

Stated that it needs a 3/4" air gap, which I was thinking should be filled with foam board.

Now I am thinking maybe reflectix needs to go NOT against exterior skin but against inner skin, as in this order: exterior skin, foam board panels, reflectix, inner skin. As noted in the post above this would provide a barrier to heat transmission through the ribs to the interior too. The key for reflectix to work appears to be no air flow and a dead air gap. Basically using the dead air space as an insulator.

Clearly, we could discuss the permutations and combinations of insulation alternatives till death. Has anyone used reflectix or foam board and can give a definitive performance rating in hot and cold climates?

[AlbertaBound]

just to confuse things more, here in Alberta bubble wrap is not considered to have any significant R-value and is basically considered very expensive vapour barrier. And as far as the reflective layer it is mostly redundant because your outer shell is already doing just that. If anything have it towards the inside to keep in the heat from your furnace or the cooling from a/c.

I am considering using "styrofold" as I have it left over from my house together with a foil backed insulation. considering using spray foam for the underside but I don't know if it will stand up to the twisting of the frame

[Cyquest]

My 69 had 3-4 inches of factory spray foam in the under carrage. I found that it sucks up water like a sponge and take time to dry out. Led to floor and frame rot where it got wet. But preserved the frame where no water was found. Carpenter ants seem to like building a colonies in it as well. Had to tear it all out to clean and paint the frame for floor replacement. Not a fun job.