BCM Community

Hello all I am new here, I recently bought a 82 Prevost Le Mirage, and as I am deconstructing the inside I came across some insulation in the ceiling that looks like it was blown in and shaved to fit the cavity's created by the roof ribs.

My question is should I remove this insulation or keep it?, I am not raising the roof we are all too short for that to mater, I was thinking of using this blown in type of insulation any way.its also in the walls below the windows.

Any thoughts?

Anthony
btw you can check out my blog at http://prevostconversion.blogspot.com (http://prevostconversion.blogspot.com)

   Welcome, "Great bunch of Bus nuts here on this board"  If it looks like it was sprayed in place KEEP IT!  It probably has a good

   seal and pretty good R rating. If you have any questions don't be shy about asking, someone will have a good answer.


   Steve 5B.......

Remove it being 28 years old it has no R valve left that type started losing R valve the day after it was sprayed on and you need to check for rust anyway it traps water. 


good luck

I would have to disagree with Luvrbus when he says to remove the insulation. It has been factory sprayed in and if you plan on having it done anyway, you would just be throwing good money away as the process is the same as it was when new. This type insulation doesn't get old with age. It's not what you call "BLOWN" in insulation but rather "SPRAYED in. Blown insulation is more like the pink stuff that is in your house attic where as Sprayed insulation is hot when applied and it forms to the attached piece/s! The blown in that WAS used in some bus applications does in fact get wet, hold moisture and cause rusting but not so in your case!
The R value of sprayed in is as good as any and to compare it, you would find the same type in most refrigerated semi trailers.

Bottom line is: keep it in, it won't get any better!

Anthony, I've checked your site out, I have the same insulation I also left it in.........the places if took out I didn't find any rust, the only rust spots I found were on the floor at the base of the walls on both sides, Prevost ran their copper lines for the defroster there........the ceiling stuff is probably still good! It's up to you!
Clifford, you have me thinking again..........lol........that's more work taking that insulation out!........lol

Do your home work Anthony if you want R valve redo it I watched Wal/Mart and others redo their refer vans for years every trailer place like Great Dane,Timplite and others redo the trailers everyday they have a shop just for that because of R valve loss but if it works for you go for it.

Well my only real concern is the Temp-coat 101 I plan on using, I plan on putting about 30 mils on the roof and an additional 15 mils on the inside ceiling and walls, since it is a acrylic latex based product I don't think it will eat the sprayed in foam, do you? also I wonder bout wire runs probably wont be much overhead thou.

Thanks for your input fellas.

Not trying to debate anyone here but to be honest, most of these trailer manufacturing companies have their own spray insulation process because they simply put, BUILD refer trailers and really any time they, the mfgr., or large company like wal-mart RE-do a trailer's insulation is not due to the R value failing but more from damaged side walls and ceilings from fork lifts, falling loads and such. If the reefer trailer is THAT old that the insulation is not good, I doubt it would even see the highway with a paying "cold" load! It would probably be sold at auction for dry storage!

What ever Ace

I know I have heard that the stuff has a life span and that it deteriorates in terms of physical strength and R value.  I don't remember how much or if it was significant but Clifford's comments hold water.  I do know that I have found it crumbling and very dark brown so I know first hand that something happens to it  after time has passed.  That stuff was 15 years old and exposed but not to sunlight.

John

yes it could be better;but you are far above  some others that only had thin fiberglass there from factory...I did a 89 5 yrs ago (prevost)and left it in..it is not perfect and at   peak r value;  but does the job for me..I would glue in foam board in the voids(if you have any)sealed with can spray foam in cracks..It is a $ question so do you normally pay for elect separate when camping? how much extra ac or heat will it require?vs redoing cost and savings....Bob

My comment would be that a bus is not a refer trailer and does not present the moisture problem of cold hot condensation so is not likely to have the moisture robbing problem of a trailer Jerry

Jerry on the contrary, buses do indeed form condensation! Down here in Florida at least! My Prevost was factory sprayed on ceiling and walls but I added to the walls with foam board! It stays cool with only 1 ac on while sitting still and 2 while moving unless I'm driving INTO the sun, then I need 3.

Antknee,
           Maybe the most important question here is how do you intend to use your bus? If it will be the occasional weekend camping trip of which probably won't happen in the deep heat of the summer or the extreme cold of winter then you may not need to go as far as you would if you were going to live in it full time. One thing to check will be smell. Does your bus have the commercial passenger bus smell that infiltrates all the walls, floors, etc.? If so you may want to consider replacing because you will always smell that smell. I cut up some left over torn out aluminum the other day & that smell was still all over everything even after a year in the outside elements. It certainly depends on the depth of your pocket. Maybe cost is not a problem. But if it is there's another angle to consider. Will you be installing roof airs? If so can you do that now & run them for a weekend to see how well they keep up. Try this when the temps are going to be above 90 & high humidity. Also start them up in the mid afternoon to see how long it takes to cool the bus down. These tests will really clear your head on what to do. Congrats on your new adventure & welcome to a great place for help.

What I found on the internet(so it must be true ;) :D), is that open  cell, especially in a moist environment tends to to deteriorate over time, where closed cell starts as soon as you spray it and plateaus after a couple of years.


With my experience with my one and only bus,  I'd second buss smell test.  :)

Antknee,

About those blowers:  Ever see a exhaust vet grill down near the toilet stool?  Most B rooms have a ceiling vent in the B room ceiling or in the shower overhead and while that works well it does stir the air it pulls up from the floor as it draws mostly from the air next to the ceiling.  While I haven't tackled this problem I have given it some thought.

Exhaust the coach of hot air quickly, from the ceiling, to cool down the interior after a "hot soak" or provide  for exterior air circ. Using blowers you can vent the air to the exterior thru a lower vent and not have to make a roof penetration that needs periodic maint.  A DC squirrel cage will push a lot of air thru a resistive duct where a fan fails.  The DC is also easily speed controlled.

Shower exhaust that is ducted down thru the wall to the under-coach area.

A simple fan on the floor will de-stratify the interior air and keep your feet from getting cold in the winter and using a furnace of any type.  A small duct running from the floor to the ceiling could be placed inside the corner of a cabinet to do the same thing.  A couple hundred cfi is all that is needed so noise won't be a factor and the motor should last forever.  No home or RV should be without this feature.

There are bay appliances that need air circulation.  Inverters, converters or just a bay that you don't want to overheat.  If there is any air restriction in the flow path a squirrel cage quickly becomes a design need.

I think you have a high reliability device that has many uses and you should keep it and use it as you see fit.

Ruminations,

John

smell ..I have a fire damage shell I'm doing now...started a thread on Ozone machine and seemed to be running one of these in a closed up bus would eliminate any residual smells...FYI

Thanks for the advice on those blowers, John I have some ideas to work with now.

As for "The Smell" I don't seem to have one, my bus doesn't smell weird to me, just dusty and dirty....

Hey do you guys think that spray foam insulation will stand up to being painted or should I strip her bare and spray temp-coat then more foam?

Honestly I didn't expect the response your all great for helping me out.

Hey do you guys think that spray foam insulation will stand up to being painted or should I strip her bare and spray temp-coat then more foam?

That depends on what type of paint.  I have used glue that went straight thru it.  You should test some and maybe others have had experience with paint.  All automotive grade paints have laq thinner in them....even acry "enamel". What is the reason you want to paint her interior foam?

Ruthie is nearly religious in her advocacy of that thermal paint with ceramic in it.  It is very effective when applied to the exterior  but the stuff is porous and will dirt up and mildew.  Do a search on me and you will find a post that is pages long on the subject...pro and con.

I'd be using Temp Coat 101, an Acrylic Latex based thermal Ceramic paint, actually the product is called Insulall, it is a lower temp version of temp-coat 101. The temp-coat 101 is good to 350 Degrees and the Insuall is only good to 212 degrees, since I wouldn't be seeing that type of heat the Insulall should work out fine, I have a small sample can of the stuff I should go test it out on the foam to see if it eats it away. Ill check out your prior thread on the subject, John

Thanks again.

For more info about temp-coat and InsulAll check out:
http://www.tempcoat.com/temp-coat-products/temp-coat-101/prod_2.html (http://www.tempcoat.com/temp-coat-products/temp-coat-101/prod_2.html)
http://www.tempcoat.com/temp-coat-products/insulall/prod_4.html (http://www.tempcoat.com/temp-coat-products/insulall/prod_4.html)

Latex will not bother it.

You are not hearing a lot of comment because people are horse from the last go around.  This a controversial topic and it is expensive.  Read all that past chatter......its what this place is all about.

John

Quote from: Jerry32 on May 16, 2010, 05:37:25 AM
My comment would be that a bus is not a refer trailer and does not present the moisture problem of cold hot condensation so is not likely to have the moisture robbing problem of a trailer Jerry

I think you would find moisture to be a big problem in a bus. Of course, it depends how you use it.

Friends of ours had to completely strip their bus which they bought fully converted. After a year or so, they couldn't stand the stink in the bus. When they took the walls down, they found that the original converter had used fiberglass insulation. Every time someone took a shower, the steam hit the metal skin and condensed, then stayed in the fiberglass. By the time they found it, they had mold everywhere. They completely stripped the bus (45' Eagle with a raised roof) to the skin, put spray foam insulation in and rebuilt the entire coach. They are no longer worried about mold. (As a side benefit, they also noticed that the coach is much warmer in the winter than it was before.)

The lesson learned is that you don't want humidity coming in contact with the shell's metal skin. Buses aren't exempt from that. The kind of insulation will greatly affect your results.

My 2 cents worth.

Mike

Welcome aboard...

Also the point about open cell insulation V closed cell insulation, is a good point. Closed cell is more expensive, but has a better R value (from what I understand) and lasts longer.

If it was me, I would strip that insulation (especially since Luvrbus recommends it, he is the resident pro on the Prevost's on here). I would strip it down to bare metal, for a couple of reasons. First, there will NEVER be a better time to do it. Second, you have no idea what condition your upper frame is in. Third, if you are doing the whole bus from scratch, why risk the insulation not being right. After all, you will want to spray foam (closed cell) all of the walls too. If you are building this bus, you want to do it right. You don't want to have regrets about "not re-insulating the ceiling" etc.

If you are doing a nice conversion, don't cut corners. But that is my opinion.

FWIW, YMMV, HTH

God bless,

John

LOL! Here's my view point on this. Being right at the finishing stages of de construction on our Eagle and having assisted in the joy of doing the same on an MCI a few years back, I found the original insulation to be pretty good stuff at the time it was installed, but with so many new and efficient methods of insulating your coach available, why not rip the old out. my main concern (first) was what condition the inside of the roof in, luckily ours is fine but did need to be re primed. I view this as the prime opportunity to get it done right the first time out. I became concerned about moisture, after the Quartzsite rally last Jan, after firing up our brand new Big Buddy, which turned the coach into a terrarium which also ruined our digital camera, Had we been parked up North at that time, I could see how easily it would have froze the doors shut.. really! ;D ;D. Any who, Now I can Have piece of mind that it will be done right and sound proofed to boot. Besides there is are no bragging rights in doing it wrong ;D ;D ;D. Drive on! :)   

Welcome Anthony. You've already made the right decision when you chose a Prevost (little bias here). Condensation will be a problem any place the foam isn't sealed against the exerior skin. Don't stuff fiberglass anywhere--that's for stick and staples that fall apart in a year. I would inspect the existing foam and if it is still solid and secure to the exterior skin, leave it. But that's my opinion and I'm a cheap bast..d LOL I had a couple of spots where a heavy foot on the ceiling broke the bond between the foam and the skin and it condensed like an open faucet. Was a serious pain to repair, since the coach was finished and required a lot of tearing apart. I originally thought I had a leak, but it dripped even when it hadn't rained for a long time. You don't want to go there, trust me. If the foam is questionable, follow the advice here and rip it out-you won't want to do it later!
Good luck and congrats, Will

I haven't seen this mentioned in a long time:  The air inside the square tubing will circulate in there and exchange heat through convection.  One side is connected to the outside skin and the other side is at least "closer" to the inside wall surface.  There is an exchange.  I have seen pics from Montana where the inside walls had these pretty little "frost buttons" everywhere.  Those were located where the screws used to hold on the paneling were located.  The screws were into ribbing and I don't know for sure if the ribbing was metal or added wood but I think it was wood.  Your are certainly not going to habitate a coach that is at minus"OMG" cold.  This does demonstrate where the heat loss is and in the pics I saw ONLY the walls had these frost buds(flowers?) on them.  The fix was two fold:  put wooden strips on the wall that are anchored to the framing and then spray foam to the added 3/4 inch the strips add to the wall for increased R factor.  By flattening the ceiling you can ad 4 inches or so of foam to the ceiling skin where it is absolutely the most needed.   FINALLY..drill little holes in the box steel framing every 10 inches and have the foam application team put a "squirt in each hole.  Filling the tubing will eliminate convection flow and filling it will prevent condensation if the tube is open somewhere.  Going over the entire friggen bus with a sharp 3/8s bit doesn't sound like much work if youaren't the one doing it.  I would be trying to get it as close to a thermos bottle as I could.  There is no end to the extent we think others should go....right?

John

John, you are ruining my trip  :o LOL, I havent gotten to the real insulation point yet or the framing yet, BUT I have been thinking I would forgo the drilling of the steel ribs altogether (or as much as possible) by welding brackets to hold the wood framing onto the ribs. Please, please............ argh!!! Now Im thinking about drilling all over the place again

The simplest way to keep condensation out of the walls/ceiling, and ruining your R value, is to apply lapped visqueen (sealed with tape) over the furring strips before applying the interior finish - HTH

BOOOO on the brackets!

Niles for the win!

All good suggestions, I think I am leaning towards tearing it out, what with the reverence everyone pays Clifford, I had better listen to him. and if there were any condensation problems I will discover them and do away with them.

Back when I was into sports cars a friend of mine and I redid a early 90's 300z. After stripping out the interior he spray foamed every crevice and opening in the unibody he could find. This significantly stiffened the car body and with the added after market sway bars and springs the car handled really well.

By drilling and filling with foam such as JohnEd suggests won't that make the box steel framing stiffer? will that be a problem or an advantage? just a thought.


OK now please forgive my naiveté  But what are : FWIW, YMMV, HTH ???

Thanks again for all your help.

Well if we told everybody ten it wouldn't be a "secret" code now would it?  Jeez Louise

Imho....in my humble opinion

FWIW...for what it is worth

YMMV.....your mileage may vary

HTH.... Hope this helps

BFF....best friends forever  grade school stuff

WTF OVER..

FUBAR..

SNAFU...

WAG....wild @$# guess

SWAG super wag

SCWAG....super colossal wag

There must be a book of these somewhere.  I would google it but what are they?

Aunt,

what with the reverence everyone pays Cliffor

Yes we do...er except maybe Ace.  Now this may clue you in a tad.  One Xmas eve a Knut was traveling thru Palm Springs and said Knut lost his engine air compressor.  That stops you dead in your tracks and it did him.  The knut went on line and asked for advice and help/  Clifford answered and together they determined that the compressor was shot.  Clifford, with his wife, drove to Palm Springs WITH a compressor he had laying around and helped the stranded Knut change it on the side of the road.  Now Clifford is no spring chicken and God knows he has paid his dues but, like the Energizer Bunny.....he just keeps on giving.  Time, advice, encouragement, parts all of it.  Yeah, reverence is a good word, respect works, endearment wouldn't be any sort of stretch and....well you get it, right?  When that knut posted his predicament Clifford's bride said we can't just leave him stranded out there on Xmas eve".  They apparently are a matched set.  He robbed the cradle on that one, also . He is a Dog.

My take on it through observation, anyway.

John

And thank you Clifford for giving me so many nice things to say.  Feels good from this end.

John, now THAT's funny! :)

My take on it...

why pay for something if it's common knowledge!

Antknee,
             Earlier when I mentioned the smell factor I didn't cover where & what all the smell comes from. I suppose you will remove the old AC vents. When you do there will be a dirt & all sorts of things mostly probably dead things that will have been inhabiting that area for who knows how long. You might get lucky & not get the SMELL but you will want to get rid of all that anyway. Now you're on your way.

Ant,

That is a great choice. Not only does it make sense, but Clifford recommends it. You are a smart man. Maybe you could save a dollar, but that would probably be penny wise, dollar foolish.

Let us know what you find.

God bless,

John

JohnEd, did you just call me AUNT? it's Ant! sheesh.... But seriously Thanks for that bit of insight onto Clifford, makes me even more satisfied with my decision to follow his advice, now I know this is probably a dead horse but I will bring it up again, but not in this thread Check my new thread coming shortly.....


TTFN

Ant,

You know that is kind of funny. I just about called you "Aunt" too. I thought it was pretty clever of JohnEd. LOL ROFL

God bless,

John

Found this on Wikipedia:

Some types of foam insulation, such as polyurethane and polyisocyanurate are blown with heavy gases such as chlorofluorocarbons (CFC) or hydrochlorofluorocarbons (HFCs). However, over time a small amount of these gases diffuse out of the foam and are replaced by air, thus reducing the effective R-value of the product. There are other foams which do not change significantly with aging because they are blown with water or are open-cell and contain no trapped CFCs or HFCs (e.g. half-pound low density foams). On certain brands, twenty-year tests have shown no shrinkage or reduction in insulating value

Interesting, I wonder which type is in my bus, anyone know? Clifford?

I'm still taking mine out just researching r value and came across this  :)

FWIW, is for what its worth, dont know the others. JohnEd, I am not religious about TC, maybe about the bus itself,  ;D, but not that. Yes, I am convinced, as we have first hand experience with it. I do know we have ran the air, and had the heat on the bus, and it is like an insulated cooler in there. We didnt spray the ceramics inside on the roof, but on the roof itself, and it is on the sides and floor. A power washer takes care of the top. We left the original spray insulation, and added more where it needed it, as well as additional insulation too. We also put spray foam in side the metal tubing inside also. Left no places empty. Maybe overkill, but, ya only get one shot at doing it right. Everyone has their own opinions, but the best anyone can do is to ask questions, as there is a lot of help on here, but, then, do your own research.

You guys are too funny ;D ;D ;D ;D ;D But, you are all a great bunch of guys. Thanks for all the great advice and help you give us. It is appreciated.

One of the LARGEST performance factors for that spray foam is "DOESN'T ABSORB WATER".  Quite emphatically.

I think open cell does and closed cell doesn't absorb water.  Wet open cell doesn't work well at all and remember that Knuts have posted that they thought there was a hole in the roof and it was leaking rain water and it turned out to be condensation.

Maybe you can post a better "findings paper" about the suitability of "open cell foam" in RV wall insulation applications.  Nobody has done that yetr as far as I know.

John

I noticed today on my XL the ceiling insulation is different than the sidewall below the window level..The ceiling is more dense and the sidewall seems porous(below window level)...ceiling is holding up very well and did except Kiltz oil base sealer;with no damage...Bob