Why I won't spray foam my bus

[o1marc]

I saw the first video a couple of years ago. After watching it I would not put that stuff in a house.

I still would probably put it in a bus if I had the opportunity. If something went wrong in a bus it is a few thousand dollars and not that hard to recover from. A house on the other hand would be a nightmare..

My bus was a budget build and spray foam didn't fit into that. I got a bunch of pink foam board and it works just fine. I have been hanging out in below freezing temps with a wood stove staying very toasty.

The things "that happen" , happen during curing in the first hour. If there's an issue it's the installers problem and not something that goes negative after time.

 

[ACamper-SKO]

The things "that happen" , happen during curing in the first hour. If there's an issue it's the installers problem and not something that goes negative after time.

I also got the impression it was the error of the installer. Which makes it more scary to me, insinuation is not the nicest job so I am sure it attracts a good amount of idiots and general hacks who do not take much pride in workmanship.

 

[firebuild]

So if I understand you correctly, you are able to heat your poorly insulated bus using "only" 4500 watts of electric heaters, with a buddy propane heater and 30K BTU propane heater (both open flame?) as back ups? Mind blowing...

At least you are actually living on your bus unlike the rest of us "under construction posers"...

LOL i was going to point that out, too. That is a LOT of heat to be throwing around.

 

[PatrickBaptist]

LOL i was going to point that out, too. That is a LOT of heat to be throwing around.

Typically all were not turned up on high though, especially not the back bed room it's never on high, not even on a real windy night and cold night.

 

[Ghrasshopper]

Patrick I find it interesting that you wouldn’t spray foam your bus for health reason be but you heat your bus with an unventilated propane heater. I think their is some major consideration that should be put into what materials are being put in the bus. Houses have a larger volume of air with constant airflow and ventilation. A bus on the other hand is a small tube that gets shut up tight to heat. That being said I sprayfoamed my bus and honestly think that rigid foam probably would have done a comparable job for a whole lot less money.

 

[PatrickBaptist]

Patrick I find it interesting that you wouldn’t spray foam your bus for health reason be but you heat your bus with an unventilated propane heater. I think their is some major consideration that should be put into what materials are being put in the bus. Houses have a larger volume of air with constant airflow and ventilation. A bus on the other hand is a small tube that gets shut up tight to heat. That being said I sprayfoamed my bus and honestly think that rigid foam probably would have done a comparable job for a whole lot less money.

I.m not using LP this year, last year I did. LP is clean burning as long as the flame is blue, you just have to make sure that it doesn't consume all the O2.
I already stated I used foam board, just not in the roof yet anyways.
I also ran a O2 monitor as well to ensure there was plenty of air to breathe and we didn't have a problem at all.

Like you said though, big difference in spray foaming an attic of a vented house vs spraying the living space of a tiny tube trying to make in non-vented while looking at the gillions of homes saying if it's good enough for the people in houses it will be just as good in my living tube....

 

[Shorty22]

Considering the end-of-life of the products we use, there are many materials that are better than spray foam.
Rock wool is a great product- it’s fire resistant, doesn’t absorb moisture and is much healthier for indoor air quality.
Rockwool is in my bus and also insulating my home without wheels

Just because the industry is dominated by foam products, doesn’t mean we should blindly follow-suit and give in to these products.

Other options are: seal gaps and penetrations with caulk or spray foam sealant, and use a cleaner material for the rest of the insulation like denim batts, rock wool, etc.

 

[o1marc]

Considering the end-of-life of the products we use, there are many materials that are better than spray foam.
Rock wool is a great product- it’s fire resistant, doesn’t absorb moisture and is much healthier for indoor air quality.
Rockwool is in my bus and also insulating my home without wheels

Just because the industry is dominated by foam products, doesn’t mean we should blindly follow-suit and give in to these products.

Other options are: seal gaps and penetrations with caulk or spray foam sealant, and use a cleaner material for the rest of the insulation like denim batts, rock wool, etc.

Better in who's opinion? If we used the best of everything we would be driving $250K Skoolies. The industry is dominated by the best product for the money.
Rock wool does absorb moisture, I stuck a piece in a glass of water and it dripped for awhile after I removed it. It's more expensive than rigid which is why most shy from it.

 

[kazetsukai]

Rock wool does absorb moisture, I stuck a piece in a glass of water and it dripped for awhile after I removed it.

I used rockwool in an aquaponics greenhouse as medium for seed starters for this reason. You could spray/run the pumps for 10 minutes every two hours and maintain a moist environment, kind of important when running off solar power. Largely where my DC electrical skills came from.


As for spray foam insulation/safety, seems like most other things: you either do it right or you don't. I can imagine a few installations every 10,000-100,000 going haywire and causing serious issues for the occupants (whom are not "buttheads" or "complaining" when they point out the obvious). I'd still consider it, but I think I like rigid insulation + great stuff in the cracks, so I'm not "manufacturing" the product on-site.


I need to look at your build thread/rig. I had two 1500W heaters and they didn't make a dent below 40F ambient. Only once I had the split in was I able to maintain decent temperatures in the cabin.

 

[Borealis-SKO]

The great thing about a bus build is that it's yours to make personal choices. No two builds are the same. From my perspective, I ignore most of the sage insulation advice given by well-meaning folk in warmer climates. I'm in Canada where we have just two seasons: Winter and Construction. What you can get away with down south of the Mason Dixon line isn't going to work up here in mid-January. The more you are exposed to extreme climates, the more you'll pay for any sins or ommissions in your insulation. If you're in the temperate US, you can probably get away with murder and think you've done a great job.

There are four elements to a successful build from an insulation perspective.

1. Make the outer skin as airtight as possible. This includes doors and windows. Of course, if you're airtight, you're probably also watertight and you won't have to worry later about leaks or rusting in your interior. This is the point where you need to seriously evaluate whether your old bus windows are really up to the job. Multi-pane argon-filled windows are really expensive, but worth it in the long run, if you are going to brave serious winter weather.

2. Insulate the crap out of your outer skin. Every dollar spent wisely here adds comfort and reduces energy costs down the road. You'll spend more time curled up beside the woodstove and less time making trips to the woodpile.

3. Completely seal your insulating layers from your living space with vapour barrier. Condensation only occurs on cold surfaces, so keep the moist interior air away from the insulation and the cold surfaces behind it. With the exception of sprayed closed cell foam, most insulating materials make poor vapour barriers. Closed-cell foam sheets are good, but you have to pay special attention to sealing ALL of the joints.

4. Use an air/heat exchanger to let your bus breathe. Fresh air from the outside needs to circulate inside the bus and you will want to exhaust excess moisture, carbon dioxide, carbon monoxide, cooking smells, bathroom smells, chemicals and so on. Outgassing of chemicals occurs from common building materials such as plywood, foam sheet insulation, flooring, glues, paints, varnishes, man-made fabrics, etc. Plan the airflow so your fresh air is going into living spaces such as your bedroom and your exhausts are pulling from the smelly parts. You also need to ensure there are no dead air areas such as behind furniture where cold moist air can collect and cause mildew. Dead air spots are effectively unheated. The more efficiently you move warm air around the interior of your bus, the fewer issues you'll have with mildew and the more comfortable your whole bus will feel.


So far as the actual insulation process, I often see bus or van builds on YouTube where the owner is making really big mistakes and sometimes wasting money on quite ineffective methods.

Sound insulation - most sound insulation products are poor thermal insulators. Rattletrap style products which are designed to reduce noise in an uninsulated panel van become redundant if you're going to cover them, especially with spray foam. These products are designed to reduce resonant noise, where the panel essentially acts like a speaker cone or the head of a drum. Spray insulation is going to adhere directly to the metal skin of your bus and completely deaden any resonance. Rattle type products have zero thermal value and you're just throwing away money in this instance. Also, if you're using something like Rockwool to insulate your bus, make sure you're buying the type that's for thermal insulation, not for sound.

Reflective barriers - Reflective barrier products such as Reflectix have ZERO insulation value in a wall and are ineffective unless they have at least a one-inch air gap on the shiny (reflective) side of the barrier. If you put Reflectix directly against foam insulation or the skin of your bus, you have at best installed an expensive vapour barrier. These products are designed to reflect radiant heat (ie heat travelling through the air). A survival tent made with this material would be great in the desert with the shiny side out or in the arctic with the shiny side facing in. So if your reflective barrier is working at all in hot weather, it's pointed the wrong direction in cold weather. Other than perhaps as window shades, reflective barrier products have no place in your bus insulation plan.

Thermal bridging - Metal struts and of course the metal skin of your bus are the enemy when it comes to conductive heat loss. There is no point in trying to insulate behind a metal strut or structural component that is essentially fused to the outside skin with rivets. From a thermal point of view, they will act as a single piece of metal. Focus your energy on insulating on the interior side of structural elements. If you simply screw your interior ceiling material to the metal struts, even if you insulated the ceiling, those struts are going to transfer heat and create cold bands across your ceiling (or hot zones if you're in Moab trying to stay cool). If the metal struts on your bus are vertical, consider adding horizontal wooden struts on which to mount your finished ceiling material. The intersection between the opposing metal and wooden surfaces is minimized and so too then is the thermal bridging.

So small decisions can have a big impact on the effectiveness of your insulation. In a bus, spray foam insulation isn't any higher risk to your family than sheet foam and probably less risk than carbon monoxide from additional heaters needed due to ineffective insulation. I wouldn't put any stock in the horror stories from the media. You need good ventilation in any case, which is something that many older homes lack.

Safe travel in your journeys and good luck to all with their build adventures.

 

[Firepuncher]

The great thing about a bus build is that it's yours to make personal choices. No two builds are the same. From my perspective, I ignore most of the sage insulation advice given by well-meaning folk in warmer climates. I'm in Canada where we have just two seasons: Winter and Construction. What you can get away with down south of the Mason Dixon line isn't going to work up here in mid-January. The more you are exposed to extreme climates, the more you'll pay for any sins or ommissions in your insulation. If you're in the temperate US, you can probably get away with murder and think you've done a great job.

Here is where many bus/van insulation jobs going wrong.

There are four elements to a successful build from an insulation perspective.

1. Make the outer skin as airtight as possible. This includes doors and windows. Of course, if you're airtight, you're probably also watertight and you won't have to worry later about leaks or rusting in your interior. This is the point where you need to seriously evaluate whether your old bus windows are really up to the job. Multi-pane argon-filled windows are really expensive, but worth it in the long run, if you are going to brave serious winter weather.

2. Insulate the crap out of your outer skin. Every dollar spent wisely here adds comfort and reduces energy costs down the road. You'll spend more time curled up beside the woodstove and less time making trips to the woodpile.

3. Completely seal your insulating layers from your living space with vapour barrier. Condensation only occurs on cold surfaces, so keep the moist interior air away from the insulation and the cold surfaces behind it. With the exception of sprayed closed cell foam, most insulating materials make poor vapour barriers. Closed-cell foam sheets are good, but you have to pay special attention to sealing ALL of the joints.

4. Use an air/heat exchanger to let your bus breathe. Fresh air from the outside needs to circulate inside the bus and you will want to exhaust excess moisture, carbon dioxide, carbon monoxide, cooking smells, bathroom smells, chemicals and so on. Outgassing of chemicals occurs from common building materials such as plywood, foam sheet insulation, flooring, glues, paints, varnishes, man-made fabrics, etc. Plan the airflow so your fresh air is going into living spaces such as your bedroom and your exhausts are pulling from the smelly parts. You also need to ensure there are no dead air areas such as behind furniture where cold moist air can collect and cause mildew. Dead air spots are effectively unheated. The more efficiently you move warm air around the interior of your bus, the fewer issues you'll have with mildew and the more comfortable your whole bus will feel.


So far as the actual insulation process, I often see bus or van builds on YouTube where the owner is making really big mistakes and sometimes wasting money on quite ineffective methods.

Sound insulation - most sound insulation products are poor thermal insulators. Rattletrap style products which are designed to reduce noise in an uninsulated panel van become redundant if you're going to cover them, especially with spray foam. These products are designed to reduce resonant noise, where the panel essentially acts like a speaker cone or the head of a drum. Spray insulation is going to adhere directly to the metal skin of your bus and completely deaden any resonance. Rattle type products have zero thermal value and you're just throwing away money in this instance. Also, if you're using something like Rockwool to insulate your bus, make sure you're buying the type that's for thermal insulation, not for sound.

Reflective barriers - Reflective barrier products such as Reflectix have ZERO insulation value in a wall and are ineffective unless they have at least a one-inch air gap on the shiny (reflective) side of the barrier. If you put Reflectix directly against foam insulation or the skin of your bus, you have at best installed an expensive vapour barrier. These products are designed to reflect radiant heat (ie heat travelling through the air). A survival tent made with this material would be great in the desert with the shiny side out or in the arctic with the shiny side facing in. So if your reflective barrier is working at all in hot weather, it's pointed the wrong direction in cold weather. Other than perhaps as window shades, reflective barrier products have no place in your bus insulation plan.

Thermal bridging - Metal struts and of course the metal skin of your bus are the enemy when it comes to conductive heat loss. There is no point in trying to insulate behind a metal strut or structural component that is essentially fused to the outside skin with rivets. From a thermal point of view, they will act as a single piece of metal. Focus your energy on insulating on the interior side of structural elements. If you simply screw your interior ceiling material to the metal struts, even if you insulated the ceiling, those struts are going to transfer heat and create cold bands across your ceiling (or hot zones if you're in Moab trying to stay cool). If the metal struts on your bus are vertical, consider adding horizontal wooden struts on which to mount your finished ceiling material. The intersection between the opposing metal and wooden surfaces is minimized and so too then is the thermal bridging.

So small decisions can have a big impact on the effectiveness of your insulation. In a bus, spray foam insulation isn't any higher risk to your family than sheet foam and probably less risk than carbon monoxide from additional heaters needed due to ineffective insulation. I wouldn't put any stock in the horror stories from the media. You need good ventilation in any case, which is something that many older homes lack.

Safe travel in your journeys and good luck to all with their build adventures.

Well you beat me to it. All of this is spot on. I'm in a spat with a guy on Instagram who is planning to put 10 foot lengths of hat channel on reflectix on the floor of his bus with hydronic heat tubing under the channel and foam in between. I tried...

I plan all of your points including thermopane windows of some design. I have been in heating for over 30 years and marvel at some of the things people come up with. I am looking at an hrv made for mini homes. A direct vent LP boiler and a radiant dv LP fireplace made by Valor in North Vancouver.

Where in Canada?

Steve

 

[Borealis-SKO]

Well you beat me to it. All of this is spot on. I'm in a spat with a guy on Instagram who is planning to put 10 foot lengths of hat channel on reflectix on the floor of his bus with hydronic heat tubing under the channel and foam in between. I tried...

I plan all of your points including thermopane windows of some design. I have been in heating for over 30 years and marvel at some of the things people come up with. I am looking at an hrv made for mini homes. A direct vent LP boiler and a radiant dv LP fireplace made by Valor in North Vancouver.

Where in Canada?

Steve

Thanks, Steve.

I'm in Northern Ontario. -12C, snowing and blowing hard here right now.

 

[Firepuncher]

Cool, I'm visiting my daughter down in The Hammer

Stay warm!

 

[EastCoastCB]

Hey- I'm VERY south of the Mason Dixon line and I still endorse insulating the holy hell out of a bus.

 

[Firepuncher]

Well almost all the theory is the same. Only real difference I can think of is sometimes which side of the insulation you place the vapour barrier

S

 

[kidharris]

1000000 homes with spray insulation, 1 butthead complains. Scientific enough for me to say it is safe .

Your right. What a butthead!! Complaining because it is killing his family and destroying his home.


You got something to back up that 1000000 homes business?


What science are you talking about?



The other problems, more common problems are mold, rotting lumber, and rust from ventilation and vapor barrier issues. There are also some very serious fire related issues ranging from toxic gases, runaway fires, and very serious fires resulting from the foam burning, especially in metal buildings - foam that is supposed to not burn. If you bother to do the research that crap is not nearly as safe as you make it out to be.

 

[kidharris]

Last year I was just using LP heaters, this year electric atleast for now anyways. But yeah it keeps it plenty warm, some nights we have had to turn them down or crack open a window or 2. The LP heaters are the catalytic style. Do have 2 LP furnaces as well 36k each but never have used them but once and that was just to heat up the bus.

We have been living in it for a year now actually.
"under construction posers" LOL.
Try living in it while doing the conversion in an RV park, that's how we started out with the bus, not in a park anymore though.
So in my case it sure wasn't feasible to rip off all the paneling and spray foam it. Then on top of it I just don't believe it's a safe measure either, others can think and claim what they want about the spray foam without being able to scientifically prove it, but my family doesn't have to suffer it so it's not my problem and no point in arguing it.:whistling: But it's not something that HAS TO be done to live in it comfortably at all unless your talking about crazy cold climates which -6F is as cold as it's gotten in my region for a long long time. Foam board, reflectix, and HVAC tape works great.
Just wanted to share with others that it's very possible to live in a bus and be comfortable without the high dollar spray foam treatment.
In the summer I have 2x 15k RV roof air units that kept it in the lower 70s when it was in the high 90s to 100F no problem. Wasn't parked in the shade either.

Something that I noticed is that most of the buses that I have seen foamed also removed most of the windows, which also removed most of the draft, most of the solar heat gain in the summer, and most of the un-insulated outside surface area. This probably accounts for more of the energy effeciency gains than a little extra R value in the foam but is seldom credited.

 

[kazetsukai]

Your right. What a butthead!! Complaining because it is killing his family and destroying his home.

This...


Two things can be true simultaneously:

1) The OP is borderline scaremongering, considering how much spray foam is used successfully in a variety of applications.

2) Poo-pooing the victims of botched installations is borderline evangelism. People can screw up, products fail.

 

[kidharris]

***Sarcasm Alert ***
Wait a minute, first you tell us you are able to heat your poorly insulated bus with "only" 4500 watts of electric heaters, and now you assert that you can cool your bus with 30K worth of air conditioners. Again, mind blowing.... At least you didn't say "only" 30K this time.

But like I previously said, at least you are actually living in your skoolie... Rock on brother.

Rick
<><

I don't understand this conversation, what do you mean 30K of air conditioning. 30k btu, 30k tons, 30k watts

 

[kidharris]

I watched both videos. Some of the naysayers made very cogent points, IMO.

In particular, the guy who said essentially 'this isn't being produced in a factory, the factory is your home' is spot on. You're depending on a chemical reaction between two quantities of reactants, in an environment where there are numerous variables that differ from job to job. I can see where there's all sorts of things that could go wrong. And even when things go right, you're inevitably still going to have some quantity of one component or the other that didn't react. It would be impossible to not have some unreacted precursors no matter how good you were. There also appears to be the possibility of side-reactions creating new compounds in high-heat (guessing there, but the admonition against high exothermic heat & formaldehyde where the foam itself wasn't supposed to contain any would suggest that).

I am curious on what the long-term off-gassing picture looks like considering a properly-done job w/ modern formulations, compared to factory-produced foam board.

I'm necessarily off the foam train, but it is food for thought. At least to me. Thanks PB.

I re-roofed a home in Charleston S.Carolina back in 91, had to replace some decking in 1 area. At some point in time some one stuck some early formula foam in the attic. I noticed that it had pulled away from the sides of the enclosure (2x4s), I touched it and it disintegrated and fell to dust. I assumed off gassing probably caused by heat.