Ceiling insulation

[JohnEd]

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

[robertglines1]

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

[Antknee]

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.

[JohnEd]

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.

[Antknee]

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/insulall/prod_4.html

[JohnEd]

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

[MikeH]

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

[John316]

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

[Van]

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! . 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 . Drive on!    

[PP]

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

[JohnEd]

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

[happycamperbrat]

John, you are ruining my trip  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

[niles500]

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

[JohnEd]

BOOOO on the brackets!

Niles for the win!

[Antknee]

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.