Ram Promaster Forum banner

1 - 20 of 24 Posts

·
Registered
Joined
·
835 Posts
Discussion Starter #1
I have space between roof & roof ribs to put insulation....is this a good idea or put it over the ribs?????
I have enough to put 2 layers of EZ cool on roof, is this a good idea?????
 

·
Premium Member
Joined
·
8,814 Posts
I wouldn’t as that and Reflexic and other silver covered foam are radiant barriers and need an air space. They are not effective at preventing conduction heat or convective heat gain or loss. Search the forum on the subject of insulation before waisting money and time on something so poor.
 

·
Registered
Joined
·
835 Posts
Discussion Starter #3
tks again.....amazing the # of products and ways of accomplishment .....so much for sleep.....me thinks perfection not possible @ affordable $$$ without rusting the van out
 

·
Registered
Joined
·
835 Posts
Discussion Starter #5 (Edited)
well...got EZ in.....now for the drop ceiling....so far have all fingers & no holes in roof.....really like all wood sides, ceiling, floor I saw here whole lot more with the little I have accomplished....not going to finish drop ceiling today and ups delivered flooring today on Sunday....slow down and enjoy the learning curve....MsNower your curved ceiling ribs are admired ....
 

·
Registered
2014 136” HR
Joined
·
5,557 Posts
You are setting up disaster, begging for rust. Warm air will rise, moisture will condense on the cold metal roof. Never ever have two moisture barriers unless you are absolutely certain moisture cannot get between them. Take it out or at least glue it down.
 

·
Premium Member
Joined
·
8,814 Posts
Sad but good advice. Glue up 1" polyisocyanurate with beads of great stuff gaps and cracks running across the van or Thinsulate glued with 3M 90 adhesive. I can’t recommend anything else. Read the insulation forums! So easy to avoid issues and the need to redo or just do what you want and don’t ask us. Once you ask we will be brutally honest in the nicest way we can.

https://www.homedepot.com/p/Thermas...-Rigid-Foam-Insulation-Board-787264/100549260





https://www.ebay.com/itm/3M-Thinsul...m1ead2f222b:m:mQsMt9R9kVO_5FNr6jaI3KQ&vxp=mtr

[ame]https://www.amazon.com/3M-90-24-Spray-Adhesive-17-6-Ounce/dp/B0002BBV2S/ref=sr_1_3?ie=UTF8&qid=1512350402&sr=8-3&keywords=3m+90[/ame]
 
  • Like
Reactions: baitbegger44##

·
Registered
Joined
·
835 Posts
Discussion Starter #10
You are setting up disaster, begging for rust. Warm air will rise, moisture will condense on the cold metal roof. Never ever have two moisture barriers unless you are absolutely certain moisture cannot get between them. Take it out or at least glue it down.
Is it ok to cover metal floor with a rug....not for sound or insulation....but for bare feet...and check it daily for moisture retention...if wet roll up and air out van????
 

·
Premium Member
Joined
·
8,814 Posts
I would get a rug without a rubber backing but even if you do, check it once in a while. An insulated floor is a comfort and easy to do. Mine is just 1/2” of insulation board- polyisocyanurate. The polyiso is best in that it does not absorb moisture due to the aluminized surface and on the ribs of the floor there is some air space to let the reflective surface increase the insulation. Which is then covered by 1/2 inch of a good hardwood plywood running front to back between my cabinets. It is held down by just a few things. Basically it floats, although it cannot move or come up. I painted that for the finished floor but found tiny stones got under my heel barefoot (evening preference) and so I put in a cheap carpet off a roll from H-D. Now the floor is warm, flat (no ribs) no squeaks and no moisture. It was a bit of work but not that bad. BTW I have removed it several times with my modular cabinets/dinette to use the van as a van and NO MOISTURE!
 
  • Like
Reactions: baitbegger44##

·
Registered
Joined
·
127 Posts
You are setting up disaster, begging for rust. Warm air will rise, moisture will condense on the cold metal roof. Never ever have two moisture barriers unless you are absolutely certain moisture cannot get between them. Take it out or at least glue it down.
why is this seen as a rust concern, compared to aluminum backed polyiso? thanks!
 

·
Premium Member
Joined
·
8,814 Posts
Poundsand, On the floor-Because the polyiso won't absorb the water vapor and then let it condense on the cold floor and because the air gaps allowed under the polyiso give a way for any liquid moisture to evaporate, and ther probably will be some someday. A rubber backed carpet will hold moisture, trap it below the rubber, and never allow it to evaporate. Thus if you go the carpet route get one with a jute back as it is porous to vapor.
On the ceiling- The two vapor barriers will at times have the dew point between them and vapor will turn to liquid condensate. That sealed area which can be against the van, between the layers or on the interior layer needs a way to escape as vapor or liquid. Sealed closed cell aluminized multi layer insulation is a bad choice as Ms.Nomer points out because it tends to trap the water. The international Building Code for Residences (IBCR) specifically forbids multiple vapor barriers for this reason. Wood rots if there is moisture present and steel will rust. Science is you friend here! A single layer of Polyiso doesn’t allow condensation between the layers so it is ONE vapor proof product. If you install it with the sealed beads of foam running across the van then condensate between it and the steel can migrate to the edges, down the walls and into the perforated scupper at the bottom pinch clamp. This is proven to work in the driver’s and passenger’s doors as water sheets down the glass, some enters the door and it leaves at the bottom pinch seam there. There is moisture but it is allowed to dry. Double vapor barriers prevent that.
 
  • Like
Reactions: baitbegger44##

·
Registered
Joined
·
127 Posts
:confused
But the two layers he's talking about isn't trapping wood or steel in between - that's the concern, as I understand it - with multiple layers in residences; you cant sandwich studs for example. If it trapped condensation, it'd trap it in between itself, not the steel.
 

·
Premium Member
Joined
·
8,814 Posts
Sorry about that but I reread my explaination and I can’t think of a better way to tell you. Perhaps someone else can come to the rescue here. If you don’t believe what you are being told or don’t like the answer or don’t want to take the advice proceed any way you want. This is a screw-up-your-own-van-any-way-you-want forum. Go nutZ.
 

·
Registered
Joined
·
127 Posts
I'm not the op, and won't be doing it that way - just trying to understand. The residential standards argument doesn't seem to apply, as I read them.
 

·
Registered
MMXVI - L2H2 in IN
Joined
·
4,282 Posts
As shown moisture will get trapped between the layers of none breathable material. The OP needs to seal the EZ Cool together and seal them to the roof. If the EZ Cool was replaced with 2 layers of breathable insulation it will dry to the interior, just like every car ceiling does.

Joseph lstiburek of Building Science Corp is a good source.
 

·
Premium Member
Joined
·
8,814 Posts
I'm not the op, and won't be doing it that way - just trying to understand. The residential standards argument doesn't seem to apply, as I read them.
The situation is analogous as in both there is a cavity which is insulated and vapor filled. In Residential construction the condensate forms on the exterior cold (winter) wall and upon warming has to escape. It does so as vapor through the exterior siding since house wrap and all sidings approved by the IBCR allow that, or it flows down the exterior wall as liquid to the rot resistant bottom plate, and through weep holes in masonry sheathing.. In the van the condensate forms similarly on the interior of the steel wall and the moisture moves down the wall to the scuppers or re-vaporises and passes into the heated compartment. Several layers of vapor barrier prevent this from happening and the moisture remains in the cavity. One of the reasons I like polyiso is the dew point for that condensation is often in the middle of the foam and so that prevents the condensate forming in the first place. Foamed-in-place insulation is probably best at this but has it’s own complications. Batten insulation like glass fiber and others allow the dew point to be where air is present and so condensate will be more likely to form in the insulation. Avoid ANY interior vapor barrier in these products as the only escape for the condensate is back to the interior via revaporization.
All this is stated in somewhat general terms and each application needs to be thought through to allow either the prevention of condensate or the removal of it.... Paraphrasing MsNomer here.
You say as you read them? You have a IBC-R or IRC manual? Good for you.
 

·
Registered
Joined
·
127 Posts
Ah, you're talking about the skin and the insulation as the two layers, not the two layers he was installing. That makes more sense.

I don't have the code, but am somewhat familiar with them having built a house. Incidentally, they do actually end up with some unfortunate requirements regarding vapor barriers that many feel are outdated (iirc) and leads to trapped moisture.
 

·
Super Moderator
Joined
·
10,225 Posts
Building codes are designed to avoid litigation first and protect second, typically ;)
 
1 - 20 of 24 Posts
Top