Reflectix Reflective Insulation

[LeeJ]

Originally Posted by 65CV

There has been quite a bit of insulation discussion on this forum. I summarized my reasoning for Prodex and a double-layered installation method using air gaps that allow some ventilating air flow -- starting in this post, which has links to three very good threads on the subject. There are pics of the installation method later in the thread. We're happy with the results.



We did cut leftover prodex as window covers and they make an incredible difference.

Could you redo the link to "this post" it doesn't auto load.
Thanks
Lee

[perryg114]

The silver duct tape is good for sealing edges. You don't want to seal at the bottom because you want any water to run down to the C-channel. Radiation is radiation. Light is radiation. Heat radiation is also light but at a wavelength your eyes can't see. So the aluminum reflects the heat energy in the IR or in the visible. Heat hits the aluminum coating and is then reflected back to where it came from. The aluminum heats up since it does not reflect all the heat. Since the emissivity (IR reflectance) is poor, not much heat is radiated from the other side. If it is touching something it conducts that heat to whatever it touches. If it touches the aluminum skin the heat goes right through it. If there is air between the coating and skin the air is much worse at conducting heat than the skin is. It helps if there is an insulator between the front and back layer of aluminum coating and that is why they put bubbles or pockets between the front and back surface. So now you have that thin layer of not very good insulation, if the front and back of the stuff are touching something. If you put foam in there as well you at least have some real insulation in addition to a non-perfect radiation barrier that is thermally shorted wherever it touches something. You also have to consider that when new, the aluminum will reflect about 90% of the heat energy. As it gets dirty and mold grows on it etc, the reflectance goes down and eventually you will have only the R-value of the air pockets between the front and back surface which is not good. So you really want some real insulation in there to reduce the conduction of heat. The radiation barrier reduces the heat load the conventional insulation has to deal with. There is room for two layers of 1/2" RMAX and one layer of radiation barrier. The prodex may only allow one layer of RMAX. So now you know the physics of what you are doing. Radiation barrier is designed to reduce the heat energy or temperature difference that your conventional radiation has to deal with. Lets say you put this stuff in your attic. You just staple it to the ceiling joists and most of the material has air on both sides which is what you want. This may reduce the heat in the attic so now you are dealing with temperature of 100F instead of 140F. The heat conduction through the conventional insulation increases with the temperature difference between the hot side and the cold side.



Perry

[goshawks00]

Perry is the RMAX you spoke of the polyisocyanurate (sp?) insulation and if so how do you get it to 'bend' around the ceiling curvature? Also would you apply directly to the back (in contact with) Prodex?
Thanks,
Barry

[65CV]

Originally Posted by LeeJ

Could you redo the link to "this post" it doesn't auto load.
Thanks
Lee

Funny, it loads for me. Different browser maybe.

it's post 103 here:
http://www.airforums.com/forums/f109...n-88673-2.html

[perryg114]

I would not use adhesive with radiation barrier just tape any seams to reduce air movement. If it touches the RMAX then so be it. Yes RMAX is the polyisocyanurate foam with aluminum on front and back. With the RMAX you slit the back side as many times as you need to get it to conform with the curves. I expect you would need wedge shaped cuts like an orange to make it fit the compound curves. You can cut it all the way through and do it piece meal if you want then tape the seams with the silver duct tape. You can do the same with the radiation barrier.


Roof Insulation Wall Insulation Polyiso Specialty Products | Rmax

Tape

Nashua Tape FlexFix 1-7/8 in. x 361 ft. Flex Duct Tape-684098 at The Home Depot#

Here is the radiation barrier stuff

Shop Reflectix 25-ft x 48-in Reflective Insulation at Lowes.com=

Perry

[Frank's Trailer Works]

I use Reflectix on every single job. I swear by it. Heat from the outside is reflected back out and cool from the inside is reflected back in. It works in reverse too. Highly effective stuff. I wish it was around when I did my own trailer. I believe in this product so much that I am considering gutting my entire trailer out to do it.


For the end caps, I cover them before installing them. Care must be taken to not put the insulation where the fiberglass meets the rib. The thickness of insulation will effect getting it back into proper alignment. I use a cabinet grade spray contact cement to adhere it to the end cap. All seams get covered with aluminum tape.

The Reflectix acts like a big decal if you spray the skin with the contact cement, allow it to dry, then spray the back side and put the wet glue into the dry. Cutting things precisely is very important. I go right up to the ribs. Any seams are covered with aluminum tape.

I then do the wiring.

Next I install a second layer held behind the backside of the ribs. The aluminum tape covers all the ribs and gaps and makes it into a big ballon. The air gap in between the two layers is about 1 1/8". Once the first layer goes in I have to work inside the trailer with all the windows open since the heat from my shop light builds up quickly.

[goshawks00]

Next I install a second layer held behind the backside of the ribs. The aluminum tape covers all the ribs and gaps and makes it into a big ballon. The air gap in between the two layers is about 1 1/8". Once the first layer goes in I have to work inside the trailer with all the windows open since the heat from my shop light builds up quickly.[/QUOTE]

Frank,
See if I got this, you glue first layer to the outside skin, then tape the second layer using the backside of the ribs to hold tape which then holds second layer. This gives you the 1 1/8" gap? Wiring is sandwiched between the two layers?

[Frank's Trailer Works]

yep. So far the results have been stellar. I look forward to seeing how it worked in 40 years.

[goshawks00]

[QUOTE=perryg114;1405217]I would not use adhesive with radiation barrier just tape any seams to reduce air movement. If it touches the RMAX then so be it. Yes RMAX is the polyisocyanurate foam with aluminum on front and back.


Perry where did you order your RMAX from? Can't seem to find where there are any dealerships.
Also are you saying to put radiation barrier against the skin or hold it back away from the skin?
Thanks Barry

[LeeJ]

Originally Posted by 65CV

Funny, it loads for me. Different browser maybe.



it's post 103 here:

http://www.airforums.com/forums/f109...n-88673-2.html

"Network error" refresh or retry. Are the messages.
Have Safari as the browser. Oh well.
Thank you.
Lee

[LeeJ]

Copied it into Google. That worked.
Thanks again.
Lee

[Colin H]

Originally Posted by 62overlander

I use Reflectix on every single job. I swear by it. Heat from the outside is reflected back out and cool from the inside is reflected back in. It works in reverse too. Highly effective stuff. I wish it was around when I did my own trailer. I believe in this product so much that I am considering gutting my entire trailer out to do it.

Attachment 203836
For the end caps, I cover them before installing them. Care must be taken to not put the insulation where the fiberglass meets the rib. The thickness of insulation will effect getting it back into proper alignment. I use a cabinet grade spray contact cement to adhere it to the end cap. All seams get covered with aluminum tape.
Attachment 203837
The Reflectix acts like a big decal if you spray the skin with the contact cement, allow it to dry, then spray the back side and put the wet glue into the dry. Cutting things precisely is very important. I go right up to the ribs. Any seams are covered with aluminum tape.
Attachment 203838
I then do the wiring.
Attachment 203839
Next I install a second layer held behind the backside of the ribs. The aluminum tape covers all the ribs and gaps and makes it into a big ballon. The air gap in between the two layers is about 1 1/8". Once the first layer goes in I have to work inside the trailer with all the windows open since the heat from my shop light builds up quickly.

Hey Frank,
I thought that you were a devout Prodex guy? I stock both, & have used both, Reflectix for the past 10 years & Prodex only the past year or so, in all of the restorations we've done. Reflectix doesn't claim any "R" value & Prodex claims R 16. R 16 seems pretty optimistic for a product this thin, that isn't NASA spec, but who knows. I do know that on trailers that we used reflectix in, then filled the remaining space with fiberglass, the inside temp remains the ambient temp, with no AC running & the windows open, so when you touch the inside skin, it doesn't feel hot to the touch, however with fiberglass alone (my 59 Ambassador is a "survivor" & still has the original fiberglass), the interior skin is hot to the touch, even with AC running. We have done tests with a Pyrometer & discovered that in direct sun & 100 degree ambient temp, a polished exterior skin will hit 145 degrees. An unpolished skin will hit 155 degrees, so polishing obviously reflects some of the heat. Our problem is to reduce the temp from 145 degrees to a livable temp, in only one & a half inches. Plus we still have the thermal bridge issue caused by the ribs. I'm still "up in the air" whether the significant cost differential between Reflectix & Prodex is worth it.
Many seem to get upset about the potential condensation inside the walls, but I have never seen evidence of water between the walls, with the exception of obvious leaks or urine streams from vermin. If there is condensation, there isn't much.
Have you done any definitive tests, or is it more "seat of the pants"?
Colin

[perryg114]

Lowes usually has the stuff but the availability maybe regional. A place that sells siding probably has a source for it since they put that down first and then put the siding over it. You can use the pink or blue foam as well especially if you are going to use the radiation barrier. I like the RMAX since it has a reflective layer on it already. I think it is about $10 a sheet.

Perry

[QUOTE=goshawks00;1405258]

Originally Posted by perryg114

I would not use adhesive with radiation barrier just tape any seams to reduce air movement. If it touches the RMAX then so be it. Yes RMAX is the polyisocyanurate foam with aluminum on front and back.


Perry where did you order your RMAX from? Can't seem to find where there are any dealerships.
Also are you saying to put radiation barrier against the skin or hold it back away from the skin?
Thanks Barry

[Frank's Trailer Works]

Originally Posted by Colin H

Hey Frank,
Have you done any definitive tests, or is it more "seat of the pants"?
Colin

I have not built a test chamber with thermal imagining if that is what you are asking. This system appear to be working for me. If my shop is 40 degrees and a simple light bulb heats the interior to needing to strip to a t shirt, I think something must be going right. The trailers I have done this way have all reported great results thus far. Time will tell.
The Reflectix does state an R value. It states an R12.6 if a 1/2" airspace is created. 3 1/2" of fiberglass insulation has an R13 rating if not compressed and filling all of the space. I do not use fiberglass insulation at all. Mice love it, it soaks up water, and is just nasty to work with. The ribs are always a killer in any trailer insulating system. They allow a direct thermal bridge to the outside.

As far as "seat of my pants" Yes, my entire life has been by the seat of my pants. Flying by the seat of my pants has been been very good to me. It has allowed me to try things I never would have thought of doing.