| Ceiling insulation - is it worth it? [message #210272] |
Fri, 07 June 2013 23:58  |
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ljdavick
Messages: 3548
Registered: March 2007
Location: Fremont, CA
Karma: -3
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Senior Member |
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I've taken down the cabinets and headliner and my coach looks like the saddest hobo palace in existence. It's depressing seeing her like this, so I want to put her back together.
The question of the day is - does it really make a difference going through the trouble to scrape off the old insulation and install foam board? It seems like a lot of work, and I'm not sure of the payoff.
Opinions requested.
PS. Other than FRP board what's the cool ceiling of choice?
PPS. I have a GMC tool, so taking off the old insulation is just a matter of moving my lazy rear.
Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy
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| Re: [GMCnet] Ceiling insulation - is it worth it? [message #210276 is a reply to message #210272] |
Sat, 08 June 2013 00:17  |
Len Novak
Messages: 676
Registered: February 2004
Location: Las Vegas, NV
Karma: -3
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Senior Member |
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When I did our headliner I left in the old insulation and used some
foil/plastic bubble stuff I got as Lowes. I used foam board in the
sidewalls and kept it all flush with the ribs and stringers. There are pics
in the website somewhere.
For the headliner I used 3/16 ABS white plastic with a pebble/hair finish as
Arch had suggested. That stuff is bullet proof.
Cheers,
Len and Pat Novak
1978 GMC Kingsley
The Beast II with dash lights that work and labels you can see!
Fallbrook, CA new email: B52Rule@Roadrunner.Com
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375
www.bdub.net/novak/
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org
[mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of Larry Davick
Sent: Friday, June 07, 2013 9:58 PM
To: gmclist@temp.gmcnet.org
Subject: [GMCnet] Ceiling insulation - is it worth it?
I've taken down the cabinets and headliner and my coach looks like the
saddest hobo palace in existence. It's depressing seeing her like this, so I
want to put her back together.
The question of the day is - does it really make a difference going through
the trouble to scrape off the old insulation and install foam board? It
seems like a lot of work, and I'm not sure of the payoff.
Opinions requested.
PS. Other than FRP board what's the cool ceiling of choice?
PPS. I have a GMC tool, so taking off the old insulation is just a matter of
moving my lazy rear.
--
Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
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Len and Pat Novak
1978 GMC Kingsley
The Beast II with dash lights that work and labels you can see!
Las Vegas, NV new email: B52sRule@Gmail.com
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375
www.bdub.net/novak/
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| Re: Ceiling insulation - is it worth it? [message #210373 is a reply to message #210272] |
Sat, 08 June 2013 17:46 |
gbarrow2
Messages: 765
Registered: February 2004
Location: Lake Almanor, Ca./ Red Bl...
Karma: 3
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Senior Member |
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Larry,
Look up this message and related thread from March of this year.
There has been comment here that the sheet foam needs to be securely adhered to the inside of the sheet metal or you'll "squeak on
down the road."
Regards,
Rob M.
-----Original Message-----
From: gene barrow
Moved from Shower Pan thread to get more exposure
A,
I'm not Joe, but I am looking at a 4'x8' sheet foam board product with a foil facing called R-Max, R-Matte plus 3. Available from
Lowes and Home Depot in 1/2, 3/4, 1, 1 1/2 and 2 inch thickness.
1 1/2 thickness will fill the cavity between the trusses ( if you remove all the OEM stuff first) and will supply an R rating
approaching R-10. This is the best R rating for the thickness I have found in various insulation products.
I have removed the oem insulation from the ceiling and hope to start installing R-Max and new headliner this week. Unless some one
on the net can supply a good reason not to use this product.
The foam is POLYISOCYANURATE- probably causes cancer in rats.
Any one have any comments, questions, or suggestions?
Since posting that message I have completed removing the OEM foam and installed the 1 1/2 inch boards in all accessible bays in the ceiling and walls.
I installed a foam backed vinyl over 1/8 inch panels headliner that I bought from a wrecked coach. Insulation is in the walls but not covered with the paneling yet.
It is currently 109*F in Red Bluff at 2:47 pm.
The coach is in partial shade but with substantial areas of sides and roof exposed to direct sun. The single a/c is running and it is comfortable and cool inside. I don't have a thermometer but will get one and check temps later.
Just before noon it was only 101. I was in and out of the coach Without the a/c on. It was not uncomfortable.
In addition to the insulation I also tinted the windows and installed clear SolarGard film on the wind shield. The SolarGard film blocks infra red (heat producing} light.
I just got this coach (76 Eleganza) up here to the HOT country 2 days ago so this is the first test with real temps.
For comparison the ceiling of my 76 Palm Beach has OEM foam, one layer of reflectrix bubble wrap, and a 1/4 or 3/8 in Masonite fiberboard head liner- installed by the PO. Walls are factory stock. Windows are tinted but not with SolarGard and no film on the windshield. I've driven the PB for over ten years and 100,000 miles. Never been able to get it cool when OAT approaches 100F.
I spent far far more for the SolarGard tint than for the insulation. Did I mention exceedingly far more? I think it helps.
I will get a thermometer and compare temps inside the coaches now that they are in the same environment. Will report back.
Don't even think about removing the OEM foam with the GMC tool. I tried that.
Find and rent, borrow, or steal the tool I mentioned in the earlier posts. Automotive window shops have them to remove the glue down windshields. Looks like a sawzall wit a long spatula blade.
So is the insulation worth the effort? I vote yes eventhough it was far more work than I anticipated.
If the blown in foam mentioned by others would approach/achieve an R10 rating in a 1 1/2 in thickness I would be glad to pay $200 to have it installed.
I used 5 sheets of the 1 1/2 in R-Max at a cost of $125. But I had all the labor to remove the OEM and install the R-Max.
And for Rob M.
I didn't glue the R-Max. Just cut to fit TIGHT and tape the edges with aluminum ac tape. No squeaks that I can hear. Thanks to 4 years working on military jets.
This R-Max product is different from the white Styrofoam type foamboard that others have used. The Styrofoam does squeak. I started installing it before I found the R-Max with the higher R value.
Good luck with your project.
Gene Barrow
Lake Almanor, Ca.
1976 Palm Beach
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| Re: Ceiling insulation - is it worth it? [message #210399 is a reply to message #210390] |
Sat, 08 June 2013 20:42 |
gbarrow2
Messages: 765
Registered: February 2004
Location: Lake Almanor, Ca./ Red Bl...
Karma: 3
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Senior Member |
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A,
The R-Max product has aluminum foil on both sides. So, using the 1 1/2 in board accomplishes what you want(reflective foil in both directions) at half the labor.
The labor is much more than you think- because the I-beam shape of the ribs requires cutting 3 pieces to fill a single bay in many cases if you want to completely fill all the voids. If you use 3/4 stock you will be cutting 6 pieces to fill a single bay.
After a while; you just want it to end so you can move on to something simple like laminate flooring. You can see the fruits of your labor much sooner.
IF you can get R10 with a spray in foam and someone else does the labor for a few bills- that's a better and faster way to go
Gene Barrow
Lake Almanor, Ca.
1976 Palm Beach
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| Re: Ceiling insulation - is it worth it? [message #210427 is a reply to message #210406] |
Sun, 09 June 2013 00:16 |
gbarrow2
Messages: 765
Registered: February 2004
Location: Lake Almanor, Ca./ Red Bl...
Karma: 3
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Senior Member |
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A,
Did you install the SolarGard yourself, or did you hire someone to do it? I guess I am asking if you can buy the raw materials in a size to cover a GMC windshield?
I paid an automotive tint shop in Southern Cal. to provide and install the tinted and clear film.
The rolls they ordered were large enough to cover the windshield.
I don't know if SolarGard products are sold to retail customers.
You could install the film yourself if you can find a retail source for it.
The material is far more expensive than non infra red blocking film. So if you mess up the application it's a costly mistake.
Gene Barrow
Lake Almanor, Ca.
1976 Palm Beach
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| Re: Ceiling insulation - is it worth it? [message #210442 is a reply to message #210272] |
Sun, 09 June 2013 08:34 |
Larry
Messages: 2875
Registered: January 2004
Location: Menomonie, WI
Karma: 10
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Senior Member |
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Larry,
No matter what you decide to do for insulation, while the ceiling and front and rear caps are down, and if the sidewalls are exposed, now is the time to check for leaks. When our ceiling was down, we went to a Greater Midwest Classics rally with the coach. While there, it rained....HARD. Sounded like we were inside of a tin can with lots of people beating on the outside of the coach. No matter...I took a flashlight and inspected every inch of the bare ceiling and walls and marked the location of the leaks with a magic marker. I found leaks around the clearance lights, around the antenna, around the windshield, and lots of leaks around the side windows. I fixed or plugged every leak, took out the windows and resealed, and tested again with a hose. The last thing you want is to spend a lot of time and effort redoing your ceiling or walls only to have it stained again by leaks that could have been fixed while those areas are exposed. IMHO it is more than worth the time.
Larry 
78 Royale w/500 Caddy
Menomonie, WI.
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| Re: [GMCnet] Ceiling insulation - is it worth it? [message #210483 is a reply to message #210373] |
Sun, 09 June 2013 16:25 |
Jim Miller
Messages: 501
Registered: March 2008
Karma: 10
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Senior Member |
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> There has been comment here that the sheet foam needs to be securely adhered to the inside of the sheet metal or you'll "squeak on
> down the road."
I scraped out all the old foam with the GMC tool - found lots of roof leaks and fixed them - and then replaced with a 3/4" piece of foil/blue polyisocyanurate followed by a 1/2" piece. I pointed the foil out opposite sides. No gluing whatsoever is required and there are no squeaks. It is so simple to scrape out the old stuff and the 1-1/4" of new material provides about R-9 to separate me from many tens of square feet of roof facing the Sun.
http://www.jcmco.com/gallery/album01
You can take an x-acto knife and cut halfway through the foam, break it (keeping the foil side intact and using it as a hinge) and then tuck it up inside the lips of the ribs and flatten it into place. This wedges the board between the ribs - it cannot come out but just to be sure you can always use foil tape over the "hinge" that you cut.
After scraping the old stuff out I found several places where the 120V NM house wiring was chafing right against sharp edges in the ribs. I never would have discovered that otherwise as those locations were buried under sprayed-in foam.
--Jim Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
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Jim Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
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| Re: [GMCnet] Ceiling insulation - is it worth it? [message #210484 is a reply to message #210373] |
Sun, 09 June 2013 16:25 |
Jim Miller
Messages: 501
Registered: March 2008
Karma: 10
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Senior Member |
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> There has been comment here that the sheet foam needs to be securely adhered to the inside of the sheet metal or you'll "squeak on
> down the road."
I scraped out all the old foam with the GMC tool - found lots of roof leaks and fixed them - and then replaced with a 3/4" piece of foil/blue polyisocyanurate followed by a 1/2" piece. I pointed the foil out opposite sides. No gluing whatsoever is required and there are no squeaks. It is so simple to scrape out the old stuff and the 1-1/4" of new material provides about R-9 to separate me from many tens of square feet of roof facing the Sun.
http://www.jcmco.com/gallery/album01
You can take an x-acto knife and cut halfway through the foam, break it (keeping the foil side intact and using it as a hinge) and then tuck it up inside the lips of the ribs and flatten it into place. This wedges the board between the ribs - it cannot come out but just to be sure you can always use foil tape over the "hinge" that you cut.
After scraping the old stuff out I found several places where the 120V NM house wiring was chafing right against sharp edges in the ribs. I never would have discovered that otherwise as those locations were buried under sprayed-in foam.
--Jim Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
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Jim Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
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