Reply
 
Thread Tools Search this Thread Display Modes
 
Old 01-03-2011, 09:37 PM   #1
4 Rivet Member
 
ddstech's Avatar
 
1958 22' Flying Cloud
Folsom , California
Join Date: Jan 2010
Posts: 467
Images: 4
My insulation progress....The triple layer combo

After reading and reading with no real conclusion, I have decided to combine the two worlds of insulation together, creating a sort of super-insulation mutant. I will provide testing results soon. But so far, I am very satisfied.

I purchased prodex insulation which is a true joy to work with. It contours to the curves of the trailer very well. I used a light amount of glue (put out by sikka which I found at lowes), to stick the prodex to the aluminum inside the trailer. Then I followed that by 2" (which actually measures closer to 1.5") fiberglass insulation (the pink stuff). Then I followed that by another layer of prodex insulation. The fit of the total insulation is very good. It doesnt compress the fiberglass insulation very much which I know is a very big concern.

I realize this might be a little more (maybe a lot more) in cost, but I do hope to take the trailer during the summer months to some hot climates and having spent time in it during the summer here in sacramento, I want to do everything I can while I have it apart. And hey, its only money.

Thoughts anyone?
Attached Thumbnails
Click image for larger version

Name:	insulation.jpg
Views:	162
Size:	329.1 KB
ID:	118752  
__________________

__________________
ddstech is offline   Reply With Quote
Old 01-03-2011, 11:02 PM   #2
Rivet Master
 
1975 29' Ambassador
Reno , Nevada
Join Date: May 2003
Posts: 1,351
What strikes me is that you are not using the reflective properties of the Prodex which are its major insulating value.

I also wonder about condensation. Where will it occur in that sandwich and where will it go.

For a one-shot, the money isn't that big a deal compared to everything else, I think.
__________________

__________________
bryanl is offline   Reply With Quote
Old 01-04-2011, 12:28 AM   #3
4 Rivet Member
 
ddstech's Avatar
 
1958 22' Flying Cloud
Folsom , California
Join Date: Jan 2010
Posts: 467
Images: 4
Quote:
Originally Posted by bryanl
What strikes me is that you are not using the reflective properties of the Prodex which are its major insulating value.

I also wonder about condensation. Where will it occur in that sandwich and where will it go.

For a one-shot, the money isn't that big a deal compared to everything else, I think.
If I am not mistaken the outer layers would be reflecting both ways. The layer closest to the inside wall would be reflecting the outside temps and the layer on the outside would be reflecting the inside temp. As for condensation, I have no idea where that is going to go.
__________________
ddstech is offline   Reply With Quote
Old 01-04-2011, 07:59 AM   #4
x
 
XXXX , XXXX
Join Date: Jun 2010
Posts: 2,601
Produx works best if an air space is maintained between the outer shell and the insulation and another air space between the insulation and the inner walls. By gluing your insulation against the outer shell you do not have that air space and will not get the desired R value.
The fiberglass insulation will absorb water from any leaks that may occur and it will also absorb the condensation and the produx will help to trap that moisture in. You might want to rethink your plan IMO.
Chris.
__________________
wasagachris is offline   Reply With Quote
Old 01-04-2011, 08:08 AM   #5
Rivet Master
 
SilverHoot's Avatar

 
1967 24' Tradewind
Greenville , South Carolina
Join Date: Jan 2009
Posts: 1,097
Blog Entries: 3
I'm in the process of doing mine with Prodex right now. I agree "the stuff is a joy to work with". I agree with Chris though, I went with Prodex for it's effectiveness, not so cozy as a home for vermin, and it would not absorb water. I am doing two layers with an airspace between the shell, the layers and the inside skin.
__________________
SilverHoot is offline   Reply With Quote
Old 01-04-2011, 09:51 AM   #6
4 Rivet Member
 
ddstech's Avatar
 
1958 22' Flying Cloud
Folsom , California
Join Date: Jan 2010
Posts: 467
Images: 4
silverhoot, how are you going to create the airspace inbetween? are you just stuffing the two layers in there? Or are you putting some sort of spacers? I could glue strips of prodex to the surface then glue the sheets to that which would create air pockets right?

I guess my thinking was the two layers of prodex would create the airspace and since the fiberglass had air inbetween the fibers, it could only add to the r value not take away.

Does anybody have a contact at prodex to get some accurate technical data?
__________________
ddstech is offline   Reply With Quote
Old 01-04-2011, 10:01 AM   #7
x
 
XXXX , XXXX
Join Date: Jun 2010
Posts: 2,601
Mattkroff I have done my belly pan and used rigid styrofoam cut into 2" strips as spacer blocks. It was glued and nailed to the floor using the nails with large plastic washers. Then the prodex was glued and nailed to the styrofoam and all the edges and seams were sealed up with aluminium foil tape. Taping the seams took longer than installing the insulation. To do the shell you will of course have to skip the nails and just glue the strips to the inside of the shell. There is glue made specifically for stryofoam. Let the glue set up for a day before installing the prodex.
I hope this helps with your plans.
Chris.
P.S. here is a link to my thread starting at the point where I insulated the belly. The pics will help and there is a more detailed explanation of the process.
http://www.airforums.com/forums/f36/...tml#post908035
__________________
wasagachris is offline   Reply With Quote
Old 01-04-2011, 10:34 AM   #8
Rivet Master
 
TouringDan's Avatar

 
1966 24' Tradewind
1995 34' Excella
Lynchburg , Virginia
Join Date: Sep 2009
Posts: 2,470
Mattkroff

For home construction insulation is usually installed with the vapor barrier on the inside (warm) wall. Condensation will occur on the cold side and will evaporate to the exterior since this exterior envelope does not have a vapor barrier.

I believe that using this same logic for an AS trailer is not valid since the outside skin is alluminum which also is a vapor barrier (to my mind). So I think your sandwiched insulation idea has merit. However, I would think that using styrofoam instead of fiberglass would be better as there would be a small air gap between the Prodex and the styrofoam to allow some air flow to evaporate condensation. Also the r value for styrofoam is higher than for fiberglass. On the other hand with all the window area that an AS has, any incremental increase in wall insulation value may not mean much in terms of overall heat loss. In the end, make your own decision on how you want to insulate your AS and the test results will come later.

Dan
__________________
TouringDan is online now   Reply With Quote
Old 01-04-2011, 10:55 AM   #9
Rivet Master
 
SilverHoot's Avatar

 
1967 24' Tradewind
Greenville , South Carolina
Join Date: Jan 2009
Posts: 1,097
Blog Entries: 3
I used Prodex

Quote:
Originally Posted by mattkroff View Post
silverhoot, how are you going to create the airspace inbetween? are you just stuffing the two layers in there? Or are you putting some sort of spacers? I could glue strips of prodex to the surface then glue the sheets to that which would create air pockets right?

I guess my thinking was the two layers of prodex would create the airspace and since the fiberglass had air inbetween the fibers, it could only add to the r value not take away.

Does anybody have a contact at prodex to get some accurate technical data?
I did exactly as you are stating I used Prodex cut into strips for spacers between the shell and Prodex and then again between Prodex layers. I did call the number (720)733-1661 on the insulation4less website and verified that what I was doing would be effective. They were reluctant to respond as they usually do not provide technical assistance for buyers of such small quantities, just contractors.
__________________
SilverHoot is offline   Reply With Quote
Old 01-04-2011, 11:49 AM   #10
4 Rivet Member
 
ddstech's Avatar
 
1958 22' Flying Cloud
Folsom , California
Join Date: Jan 2010
Posts: 467
Images: 4
Silverhoot, are you pleased with the results? How's the temperatures in the summer?
__________________
ddstech is offline   Reply With Quote
Old 01-04-2011, 12:16 PM   #11
Rivet Master
 
SilverHoot's Avatar

 
1967 24' Tradewind
Greenville , South Carolina
Join Date: Jan 2009
Posts: 1,097
Blog Entries: 3
Matt,

Mine's still a work in progress, I'm still chasing down leaks and awaiting rivets right now. If you are familiar with Redding...you know I will be able to let you know the effectiveness, but not until this summer.
__________________
SilverHoot is offline   Reply With Quote
Old 01-04-2011, 12:59 PM   #12
Rivet Master
 
Dave Park's Avatar
 
2005 22' Safari
Hyde Park Place , Ohio
Join Date: Jul 2010
Posts: 972
Quote:
Originally Posted by TouringDan View Post
I believe that using this same logic for an AS trailer is not valid since the outside skin is alluminum which also is a vapor barrier (to my mind).
Good thinking. Here's why it won't work

The mechanism:

The primary source of vapor will be from the inside. Human breath raises the humidity. There is a temperature difference in the skin between top and bottom of the trailer, and from side to side during the day, that sets up a micro-circulation. The interior air gets circulated over time into the space between the shell. The humidity reaches out towards the outer skin until the air cools enough to reach the dew point, then it condenses and sits, or enough collects, drains.

Why this complicates it:

When there is a temperature difference between the inner and outer surface, the gap usually takes on an intermediate temperature. If there's a single layer of prodex in air, each side takes a 1/3rd 2/3rd split of the temp difference (so eg: 60F inside and 90F outside, the average inner space is 75F, with prodex each side will be 70F and 80F.) As you know, temperature falls down a hill, and the steeper the hill, the faster it falls. So therefore, having a layer of prodex is 50% more effective than a single air cell or layer of insulation. Two layers improves the convection/conduction by 66% instead of 50%, but radiatively insulates at 99% (two layers) around 96% (1 layer).

Fiberglass insulation works primarily by preventing airflow to reduce convection, though it's moderately effective at blocking radiation.

Hmmm, moisture.

So, the moisture is mostly likely to condense on the outermost surface below the air's dew point. Often, this is inside the inside skin on a cold day! However, it'll also be the inside of the outside skin. If you use this fiber/prodex sandwich, it'll be both between the outer skin and the prodex, but also between the prodex and the fiberglass.

I would skip the fiberglass, and arrange for two sealed prodex layers, spaced 1/3 and 2/3 between the inner and outer wall. I would paint the unseen from ground roof area with a reflective white paint, as covered in other threads, and I would install solar panels in such a way as to shade a large portion of the roof, reducing thermal load in that area.

Side note: the AS shel is its own radiant barrier if cleaned to a shiny state. Got black goop in your end caps? Buy some silver krylon and spray it silver first and you'll reduce radiant heat into the end caps by 20-30% just by doing that.
__________________
TX-16
Dave Park is offline   Reply With Quote
Old 01-04-2011, 01:10 PM   #13
Rivet Master
 
boatdoc's Avatar
 
1973 Argosy 26
Norristown , Pennsylvania
Join Date: Sep 2006
Posts: 644
Images: 1
Quote:
Originally Posted by wasagachris View Post
Produx works best if an air space is maintained between the outer shell and the insulation and another air space between the insulation and the inner walls. By gluing your insulation against the outer shell you do not have that air space and will not get the desired R value.
The fiberglass insulation will absorb water from any leaks that may occur and it will also absorb the condensation and the produx will help to trap that moisture in. You might want to rethink your plan IMO.
Chris.
Hi Chris;
You are sharp as a tack Chris and on top of it all. Thanks "Boatdoc"
__________________
boatdoc is offline   Reply With Quote
Old 01-04-2011, 01:10 PM   #14
Rivet Master
 
VIKING's Avatar
 
1955 22' Flying Cloud
Boulder Creek , California
Join Date: Nov 2008
Posts: 1,177
I installed my Prodex with no spacers between the shell & insulation. There's just a 1" gap between layers of Prodex.
It outperforms the original pink & yellow stuff by many miles. I don't think three 3/8" spaces are going to outperform one 1" space by much, if any, and it will take you a LOT longer to arrange and attach all of the spacers and such.

Best to you,

Rich the Viking
__________________

__________________
VIKING is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Dow Safetouch insulation 2vets General Interior Topics 3 07-13-2011 08:25 PM
Wheel and tire Combo Mr & Mrs S Wheels, Hubs & Bearings 2 05-09-2011 11:10 PM
Fiberglass vs Cotton Insulation GeocamperAS General Interior Topics 13 03-09-2011 08:22 AM
Insulation lmassa Belly Pans & Banana Wraps 4 02-24-2011 11:17 PM
Insulation CampUnger General Interior Topics 3 02-13-2011 08:52 PM


Virginia Campgrounds

Reviews provided by




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 05:57 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.

Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.