Lack of Insulation between Pass-Thru and Bedroom - 315RLTS

[Da Breeze]

A question might be , If this gets well insulated and the pass thru becomes cooler/warmer and the living space is the opposite will this cause condensation on one side or the other of the foam insulation?

Brian

Hi Brian,
That is highly unlikely. Insulation merely provides a thermal barrier to offset transfer of heat and cold to adjoining surfaces.
By it's nature it does not retain humidity, hence both areas would retain their relative humidity levels.
The foil-faced foam insulation, as I've outlined, would also provide for a vapor barrier to deny the ingress of humid air into a air conditioned space, which is a good thing !!

Michael

[Cate&Rob]

Hi Brian,
That is highly unlikely. Insulation merely provides a thermal barrier to offset transfer of heat and cold to adjoining surfaces.
By it's nature it does not retain humidity, hence both areas would retain their relative humidity levels.
The foil-faced foam insulation, as I've outlined, would also provide for a vapor barrier to deny the ingress of humid air into a air conditioned space, which is a good thing !!

Michael

Hi Michael,

This is really not true. (I guess it does depend on whether the outside temperature is colder or warmer than the inside, but condensation is likely to be more of a problem in cold climates)

The vapour barrier is suppose to keep the moist air from reaching the cold surface where the moisture will condense. So, going from warm to cold, first you have the interior wall, then you have the vapour barrier, then you have the insulation (which stays dry because it is outside the vapour barrier) then you have the outside wall. If the vapour barrier is on the cold side of the insulation, the insulation will get wet from moisture condensing out of the warmer inside air.

This is why your beer can sweats when you take it out of the fridge where it was dry .

Rob

[Da Breeze]

Hi Michael,

This is really not true. (I guess it does depend on whether the outside temperature is colder or warmer than the inside, but condensation is likely to be more of a problem in cold climates)

The vapour barrier is suppose to keep the moist air from reaching the cold surface where the moisture will condense. So, going from warm to cold, first you have the interior wall, then you have the vapour barrier, then you have the insulation (which stays dry because it is outside the vapour barrier) then you have the outside wall. If the vapour barrier is on the cold side of the insulation, the insulation will get wet from moisture condensing out of the warmer inside air.

This is why your beer can sweats when you take it out of the fridge where it was dry .

Rob

Hi Rob,
That is actually not the case at all.
The attached example of what I recommend has vapor barriers on both faces. Therefore, BOTH vapor barriers achieve the same moisture protection.
Also, Styrofoam cannot get wet...It is a closed cell polystyrene product that is waterproof, and the particular product illustrated actually states as much.

Michael

BTW .... Howard this stuff is 2" thick AND only costs $20 for a 4' X 8" sheet. Much cheaper AND more effective that that Lowes stuff.

[Cate&Rob]

The attached example of what I recommend has vapor barriers on both faces. Therefore, BOTH vapor barriers achieve the same moisture protection.
Also, Styrofoam cannot get wet...It is a closed cell polystyrene product that is waterproof, and the particular product illustrated actually states as much.

Michael

Hi Michael,

Closed cell insulation would definitely be a good way to go. I would expect that the foil on each side of the product in your picture is more about "reflective insulation" than vapour barrier . . . because the closed cell styrofoam is its own vapour barrier. Another great way to do this would be spray foam insulation. This is closed cell so creates its own vapour barrier, but the big benefit is that it fills all the air gaps so performs a caulking function as well. The big downside is that if you have to access anything behind spray foam insulation . . . this is a problem.

A caution on "closed cell foam" . . . not all foam (particularly cheaper ones) is closed cell. Take a piece and stick it in a bucket of water for a week and see what happens. (A learning from my boating days . . . )

Rob

[Da Breeze]

Hi Rob,
Then we agree ????
The most cost-effective and rational method to insulate that partition would be tightly cut, snug sections of 2 inch foil-faced product as I described.
Easy in and easy out.

Sometimes, folks just need an answer to a situation and can become overwhelmed with conflicting opinions.....
Ya think ?? LOL !!


BTW...Did you make it home yet or doing some sightseeing along the way ??
The Smokey's are beautiful in spring

Michael

[Canyonlight]

You probably know this, but for those that don't take a look at post #1 and the first picture. Along the front edge as you look into the pass-thru there is a drip tray that has an electrical cord access port. This drip tray is nothing but a thin piece of plastic. There's a tray on both ends of the pass-thru. They provide almost no barrier to the heat (or cold) from the outside.

If I put foam garage door insulation panels on that bedroom wall and pass-thru ceiling, do you think I'll do more harm than good? The objective is to slow down the transfer of heat and cold between the pass-thru and the bedroom and closet.

Here's specifically the product I am referencing: https://www.lowes.com/pd/Insulfoam-C...ation/50244957

Howard - I do share your thinking on insulating uninsulated areas between the storage area and the exterior as having value when properly done.

I seem to recall a post a couple years ago where one or more posters expressed some thoughts on insulating the black plastic storage wells and may have shared a picture(s.) I think he used spray foam on the exterior surface which would seem to be a good solution. Seems I have also seen some other RVs where this has been done. The light yellowish color spray foam insulation was used and looked tacky. Using a dark color would look better.

I'm on the fence to whether or not the idea to insulate the storage area rear wall and ceiling will yield heating or cooling advantages for the 315. I suspect there will still be other openings between the RV living/basement and storage area allowing for both necessary and desired air movement.

Dan

[howson]

Thanks everyone for the discussion. As always, I learned quite a bit. I'm going to go with the R-TECH. Thankfully I won't need to insulate above the open area shown in the picture since those walls face into the bedroom and rear closet, respectively. No need for insulation there.

[howson]

After looking at it again this morning I dug around my stash and found leftover Reflectix from a garage insulation project. Cut and install--super easy and no worries about sealing gaps, etc.

If you look closely at the picture of the wall on the cap side, I rolled up pieces and jammed them into the gaps above the wall.

Next is the reinstallation of the panels. That will be documented in the Electrical Mod thread.

Do I recommend this? No. Without an objective way to measure the result (or standard to compare to) I can't recommend anyone else doing the same since I have no idea if it will work, how good it will work, or if I'll come across an unintended result. (If I do I'll post!)





Thanks again for all the inputs.

-Howard

[Cate&Rob]

BTW...Did you make it home yet or doing some sightseeing along the way ??
The Smokey's are beautiful in spring

Michael

Hi Michael,

Off topic . . . I know. We did make it home safe-and-sound. All we saw of the Smokies is shown in post 19 of this thread. https://www.mygrandrv.com/fo...tlanta-Georgia LOL! Worst day of the drive home !!

Rob

[Drolaw]

After looking at it again this morning I dug around my stash and found leftover Reflectix from a garage insulation project. Cut and install--super easy and no worries about sealing gaps, etc.

If you look closely at the picture of the wall on the cap side, I rolled up pieces and jammed them into the gaps above the wall.

Next is the reinstallation of the panels. That will be documented in the Electrical Mod thread.

Do I recommend this? No. Without an objective way to measure the result (or standard to compare to) I can't recommend anyone else doing the same since I have no idea if it will work, how good it will work, or if I'll come across an unintended result. (If I do I'll post!)





Thanks again for all the inputs.

-Howard

Hi Howard - Any feedback on how this worked or didn't worked? I'm getting ready to do that same and was wondering if your solution had any success.