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Discussion Starter #1
Hi,
I just joined the forum.
I have just spent an hour reading the various posts going back in 2014. Interestingly the debate over insulation and condensation hasn't changed.
Most of you are seasoned builders or have already done many van builds.
I live in California, I just bought a 2019 Promaster. I am ready to start but the old insulation and condensation is holding me up. I am less worried about insulating than I am about causing a condensation problem....
I do not think that I will be traveling to cold areas. I am more interested in the beach and lakes, so mostly heat. My plan is to use a sound deadener followed by Thinsulate and close my walls (tongue-and-groove). Same thing on the ceiling.
I am a painting contractor and I was wondering with I should consider painting the interior cargo with a paint that would prevent condensation. is this a waste of time. After all, condensation is expected to take place, I just don't want to prevent the drying or safe run off of water.
Also, I read in the thread about Condensation and Insulation that Hein's Thinsulate (do not know who Hein is ) is different than the Amazon Thinsulate. Please advise, I do not want to buy the wrong one.
Thank you!
 

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Hi,
I just joined the forum.
I have just spent an hour reading the various posts going back in 2014. Interestingly the debate over insulation and condensation hasn't changed.
Most of you are seasoned builders or have already done many van builds.
I live in California, I just bought a 2019 Promaster. I am ready to start but the old insulation and condensation is holding me up. I am less worried about insulating than I am about causing a condensation problem....
I do not think that I will be traveling to cold areas. I am more interested in the beach and lakes, so mostly heat. My plan is to use a sound deadener followed by Thinsulate and close my walls (tongue-and-groove). Same thing on the ceiling.
I am a painting contractor and I was wondering with I should consider painting the interior cargo with a paint that would prevent condensation. is this a waste of time. After all, condensation is expected to take place, I just don't want to prevent the drying or safe run off of water.
Also, I read in the thread about Condensation and Insulation that Hein's Thinsulate (do not know who Hein is ) is different than the Amazon Thinsulate. Please advise, I do not want to buy the wrong one.
Thank you!
Hi VMil

Welcome

Condensation happens when moisture in air is cooled to the “dew point”. I’m unaware of any paint that can prevent this (it is also dependent upon the interior & exterior environments).

Sorry I can not help you with info on thinsulate.

I too was more worried of condensation than the insulation. However I was also more concerned with mould than condensation.

Now I am more concerned with World Health.

Good Luck!
 

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Thank you for responding. I hear you.... I am trying to drown my concern for world health in my van project... I am in San Francisco. We are ordered to shelter in place. Haven't left the house in a week. Good luck to everyone. Stay healthy!
 

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Thank you for responding. I hear you.... I am trying to drown my concern for world health in my van project... I am in San Francisco. We are ordered to shelter in place. Haven't left the house in a week. Good luck to everyone. Stay healthy!
Good Move ,,, Keep your mind off that mess. SF a tough spot right now & we wish you a quick & healthy triumph

Good Luck
 

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Your plan will do fine. That's what I did five years ago. We have traveled all over, including wet cold—the worst. I have done a couple of deep investigations and found no damage.

If you have the materials and a place to work, get onto it and enjoy the anticipation of the fun you’re going to have.
 

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I live in a cold climate, Toronto Ontario Canada, I dont think there is an easy answer or perfect solution when it comes to insulating a van.

The most important thing to consider is not giving MOLD the opportunity to grow.
Regardless of any products that claim not to hold moisture, I would avoid aALL types of bat insulation, with 1 exception; I am using a small amount of Rockwool in the upper wall cavity near the roof. It is a very small space, and since it is up high, any moisture should easily dissipate. Since there is limited access, It will be very difficult to get other types of installation in that spot.
For the remaining areas I will use rigid closed cell foam (extruded polystyrene) and Reflectix bubble foil (duct insulation).
The Reflectix is only 5/16" thick, and they claim it has an R value of R2. I'm no expert, but R2 seems a bit high.
Any place where I can not fit the rigid, I will be using 1 or more layers of the Reflectix. Since the outer steel skin of the van will not allow any moisture to escape to the exterior, I feel strongly against a continuous vapor barrier. If I install a vapor barrier, any moisture that gets behind it could cause mould.
One other very, very important point is to remove the humidity inside the van with an exhaust fan. If the humidity gets extremely high and I notice any condensation on the windows I will use my remote starter to run the van's A/C or defroster, both of which will dehumidify the air inside.
One final point I would like to mention is something I experienced while renovating my basement. During the renovation I installed a layer of 1.5" rigid foam, and 4" of Rockwool mineral wool on the perimeter basement walls, and left the installation exposed to the air. It was during the winter, and I broke up the concrete floor to replace the drains. The opend floor caused the humidity level to rise very high. I noticed some water puddling on the floor next to my newly insulated walls. I was shocked when I felt the Rockwool. It was completely saturated. The moist air from the basement went through the Rockwool and condensed on the rigid. When I removed the Rockwool, it was so saturated that it lookd like I just pulled it out of a swimming pool. Rockwool has a great video that shows a large amount of water being poured directly onto it, and they claim that it does not absorb any water. I had a different experience. Just saying. I think Rockwool is an excellent product, but the method of installation is key.
 

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This demonstrates why most of us here don’t recommend Rouxl or rock wool or any fiber in any more places than a substitute for better materials is not available. Reflectix is another dubious product and you are right you are not going to get R-2 from. EXP is not the best foam sheet either for several reasons. Where you researched these material is not this site I hope. I would suggest asking for advice before selecting products. There are engineers, builders, experienced van builders, and researchers here. Why not listen to them and avoid more issues.
 

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Thanks for your comments. There is an alternative to the rigid exp at Lowes that has a foil on both sides. I thought the foil would be good to stick aluminum duct tape to it, but since i dont want a vapour barrier, i didnt think the foil board was necessary.
What is your advice?
 

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That may be polyisocyanurate which I would reccomend as it can take much higher temperatures w/o deforming, has a higher R value and by being foil covered prevents condensate being absorbed. Control the condensate by allowing it to run down to the scuppers along the van’s perimeter and out the weep holes there. Glue it in with Great Stuff Gaps and Cracks run in beads vertically to allow this to happen. Buy this:
Use a polyester batting like Thinsulate in areas the sheets cannot go in like the ribs but do not fill the lower cavity, that is a scupper.
1” of the polyiso is a lot of insulation for a van but two layers might be better in cold.
All this including lots of goog information on moisture and mold is available using the Search function.
 
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That may be polyisocyanurate which I would reccomend as it can take much higher temperatures w/o deforming, has a higher R value and by being foil covered prevents condensate being absorbed. Control the condensate by allowing it to run down to the scuppers along the van’s perimeter and out the weep holes there. Glue it in with Great Stuff Gaps and Cracks run in beads vertically to allow this to happen. Buy this:
Use a polyester batting like Thinsulate in areas the sheets cannot go in like the ribs but do not fill the lower cavity, that is a scupper.
1” of the polyiso is a lot of insulation for a van but two layers might be better in cold.
All this including lots of goog information on moisture and mold is available using the Search function.
Robbyboy

There is no magic solution here. We are all experimenting as DIY in Vans which has the metal skin vapour barrier on the wrong side of warm issue.

RD’s suggestion IMO is about as good as it gets.

There are many opinions on here & loads of information. Currently, I have concluded on 2 designs are best until someone designs & posts something better.

1) Total Spray Foam Job (might solve the cold side vapour barrier problem) - look up GaryBIS

2) Rigid Insulation / Great Stuff with vertical glue beads to allow condensation drainage as RD suggested

I would not be afraid of the double vapour barrier issue of the foil. I do not believe you could create a sealed vapour barrier on the inside of the van if you tried (Partial yes - not total). Even if you were able water can leak in from outside the van. Plywood is a vapour barrier. I think it is a good idea to reduce the water vapour movement into the wall, ceiling, & floor cavities. How you use the interior of your van & the environment you use your van will have an impact. I happen to live in Canada in “leaky condo” land & I did something similar to what RD mentioned, & so far I have not seen or smelled any mould. I also did not install any mould food into my cavities (this is ultra important).
 

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At the moment, I am kind of fascinated by the slicker material in post #8 of this thread.

 

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Thank you for responding. I hear you.... I am trying to drown my concern for world health in my van project... I am in San Francisco. We are ordered to shelter in place. Haven't left the house in a week. Good luck to everyone. Stay healthy!
There are a lot of us in the SF Bay area wondering about this.

If it helps, I am involved with a company that builds "drop in electrical system kits". It comes largely built and you just install. Can be shipped and fully wiped down with cleaners and rubbing alcohol.
 

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That drainage material is designed to allow water to drain down your foundation wall, so water isn't trapped and forced into your foundation by the pressure of the soil. Or simply being held in place long enough to be absorbed by the foundation.
If you were to fasten horizontal obstructions (2x4s) all along the foundation walls, 1/3 from the top and 1/3 from the bottom and attached the drainage material in-between the 2x4s, any water trying to get to the bottom would just hit the 2x4s and pool.
Not only is the inside of the van, not experiencing the amounts of water that an exterior foundation wall experiences, but the horizontal structural ribs in the van are simply obstructing any water that would try to run down the wall. So, what's the point?
In my opinion, you're creating a space for condensation to form,..... Just so it can drain it away? I don't really get it.
Also, even if you leave a space behind your insulation and then seal around the edge of the insulation, well, there probably won't be condensation in the first place, but if for some weird reason you do get condensation on the van skin, behind the insulation, I'm confused as to where anyone thinks it would drain to(?).
From what I can see, it would run down the metal, hit the horizontal rib, then run forward into the back of the insulation.
Creating a space behind the insulation makes about as much sense to me as cutting a hole in your roof so you can catch the leak in a bucket when it rains.
I say, just don't create the space for the condensation to form in the first place.
I dunno, maybe I'm missing something.
 

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That drainage material is designed to allow water to drain down your foundation wall, so water isn't trapped and forced into your foundation by the pressure of the soil. Or simply being held in place long enough to be absorbed by the foundation.
If you were to fasten horizontal obstructions (2x4s) all along the foundation walls, 1/3 from the top and 1/3 from the bottom and attached the drainage material in-between the 2x4s, any water trying to get to the bottom would just hit the 2x4s and pool.
Not only is the inside of the van, not experiencing the amounts of water that an exterior foundation wall experiences, but the horizontal structural ribs in the van are simply obstructing any water that would try to run down the wall. So, what's the point?
In my opinion, you're creating a space for condensation to form,..... Just so it can drain it away? I don't really get it.
Also, even if you leave a space behind your insulation and then seal around the edge of the insulation, well, there probably won't be condensation in the first place, but if for some weird reason you do get condensation on the van skin, behind the insulation, I'm confused as to where anyone thinks it would drain to(?).
From what I can see, it would run down the metal, hit the horizontal rib, then run forward into the back of the insulation.
Creating a space behind the insulation makes about as much sense to me as cutting a hole in your roof so you can catch the leak in a bucket when it rains.
I say, just don't create the space for the condensation to form in the first place.
I dunno, maybe I'm missing something.
Hey RnR

In Building Science it has been around for 100s of years. Exterior Masonry walls typically have a gravity drainage cavity system behind the exterior cladding (brick, stone, etc). The new “since leaky condo”, systems are a morphed design from the masonry systems, however they are called cavity rainscreen wall systems.

You may have a chance of sealing off the van skin from condensation by performing a total spray insulation installation, however it is possible with out 100% adherence and with the road twisting and torquing of the metal van structure I would be concerned of loss adherence or breaks in the thickness of the spray insulation that could cause water vapor migration or worse collection of Rain water that leaks through the van skin exterior.

Using rigid board insulation and great stuff, you can either attempt to fully adhere the rigid with the great stuff spray foam or adhere the great stuff in horizontal strips attempting to provide a drainage path to the bottom of the van. I understand your comments regarding the horizontal ribs, however I do not believe you will be able to fully seal rigid board insulation to the van skin with a zero cavities (even if you could why wouldn’t you just go to a total spray insulation job?).

I do not believe there is a perfect solution to this part of the van build/conversions. I believe one of the best practices is to reduce the quantity of mould food within the floor, wall, and ceiling systems. That way if we do get condensation or leaking from the van skin at least mould spores won’t have food to develop & grow.
 

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At the moment, I am kind of fascinated by the slicker material in post #8 of this thread.

Harry, what fascinates you about those materials?
 

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Yeah, hopefully that didn't sound critical. Just thinking out loud.
I've owned a lot of vans over the years, but never really camped or spent the amount of time in them like the folks here or like I will whenever I finish this one. So I don't really know first hand what the condensation situation will truly be like.
But I have to imagine that if you insulate and do a good job, space or not, there really won't be condensation. At least not where there's insulation. That's my theory.
Also, a space behind the insulation really doesn't work unless there's a clear path from floor to ceiling and then an actual place to drain at the bottom. That much I know without having built a campervan before.
And I know from experience that the water that collects in the side wells below the floor, comes from water thrown off the back tire and with the rake of the van, it flows forward and just pools. So I don't really think it's intention is to carry water away from the walls.
All in all, I think it would have to be very cold out and you'd have to be boiling water for long periods, with no insulation, to get the kind of condensation that would have water literally running and dripping down your walls. I just don't see it as an issue for most of us. Especially with insulation and most having heaters that use their van in the winter.
My personal opinion is that it's not enough concern to warrant all the money and effort that went into installing the yellow stuff. Even if it was, the horizontal ribs prevent it from working as intended,.....and even if the water could make it to the bottom, unobstructed,....it will just pool up in the wells.
Just food for thought if you're considering extra steps and materials that may not need.
However, I'm known to have wacky ideas and make extra unnecessary work for myself. So, who am I to judge?
 

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Yeah, hopefully that didn't sound critical. Just thinking out loud.
I've owned a lot of vans over the years, but never really camped or spent the amount of time in them like the folks here or like I will whenever I finish this one. So I don't really know first hand what the condensation situation will truly be like.
But I have to imagine that if you insulate and do a good job, space or not, there really won't be condensation. At least not where there's insulation. That's my theory.
Also, a space behind the insulation really doesn't work unless there's a clear path from floor to ceiling and then an actual place to drain at the bottom. That much I know without having built a campervan before.
And I know from experience that the water that collects in the side wells below the floor, comes from water thrown off the back tire and with the rake of the van, it flows forward and just pools. So I don't really think it's intention is to carry water away from the walls.
All in all, I think it would have to be very cold out and you'd have to be boiling water for long periods, with no insulation, to get the kind of condensation that would have water literally running and dripping down your walls. I just don't see it as an issue for most of us. Especially with insulation and most having heaters that use their van in the winter.
My personal opinion is that it's not enough concern to warrant all the money and effort that went into installing the yellow stuff. Even if it was, the horizontal ribs prevent it from working as intended,.....and even if the water could make it to the bottom, unobstructed,....it will just pool up in the wells.
Just food for thought if you're considering extra steps and materials that may not need.
However, I'm known to have wacky ideas and make extra unnecessary work for myself. So, who am I to judge?
You didn’t come across as critical (I try not to read too much into posts regardless).

I agree with you regarding the condensation as I think it depends upon use (boiling water etc), the dew point, and the environmental conditions.

I think the majority of our insulation jobs will outlast the drivetrain on these DIY conversations, especially if we actually put some mileage on our vans exploring North America etc. I also think they are better insulated/built than many of the commercially built RVs and camper vans

Let’s hope we get those freedoms back sometime soon.
 

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As for the yellow mesh, I wouldn't read to much into it, it was just an idea.

My idea with the Home Slicker was to keep wet, saturated insulation away from the body wall to prevent rust. It would also allow some air circulation next to the skin to eventually dry out any condensation. I probably didn't need it because the Thinsulate insulation I used is hydrophobic unlike fiberglass. I also wished I had used the 6mm Home Slicker as it was difficult to get all three layers to fit in some places.

The Reflectix outer layer was used as a radiant barrier and to limit the transfer of moisture from the interior of the van to the skin.

My insulation design was not based on any testing or analysis. I just wanted to avoid the rusted out panels that I read about when fiberglass insulation is used right next to the skin. Time will tell if it was worth it.
 

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I assure you that you can easily get rime ice on bare metal surfaces. You don’t have to do a lot of boiling and you don’t have to be in a humid environment to get it. The good part is that if the environment is not humid, the ice will sublimate with no lasting effect.
 

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"sublimate" I love it when you use those science words! We more often find dew on the inside of our windows on nights it is cold outside but not freezing and we forget to open the awning window(s) a bit and have the vent closed. It doesn’t often happen if we have even an inch of opening and we have never needed to run the fan to keep it dry inside. Remember you make lots of humidity.
 
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