| Author |
Message |
Tim (Timkar)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 14, 2006 - 1:15 pm: | |
Does anyone ever use a vapour barrier between the foam (whether it is spray, board or batt) and the finished panel (whatever it may be) I have seen it mentioned for the roof, but don't recall seeing any pics of anyone using it in the walls? Just curious.... |
joe padberg (Joemc7ab)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 14, 2006 - 2:20 pm: | |
Tim I had been thinking of adding some comments to previous posts where this topic came up during the discussion. I am presently in the process of completing the insulation of my busbarn. I decided to do it as well and equal to current residential standard R 20 wall, and R 40 ceiling with particular attention paid to vapour barrier sealing. This necessitates the usage of " poly pans" at every location where a hole appears in the vapour barrier plastic. In my case I have lots of them, since I installed an overabundance of them,seeing that I have gotten tired of tripping over extension cords. It also important to use generous amounts of "acoustical sealant" to ensure that a seal is maintained, otherwise the whole excersise is for nought. To get some idea of the importance of this, I came across a study, experiment that was conducted in Wisconsin over a two year period where they used nine test panels all four by eight insize the warm side at room temp and controlled humidity and the outside of the panel facing north exposed to the elements. The conclusion was, when two holes had been added to simulate the installation of outlet/switch boxes. the energy and humidity requirements increased by an average of some forty percent. It seems to me, that this is one area that perhaps has not been paid enough attention to by the bus converters. This is the reason why you will end up with reduced insulation effectiveness and read of cases where moisture trapped inside the wall ends up staining the exterior, never mind that it is eating the bus structure by encouraging rust. Joe. |
Tim (Timkar)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 14, 2006 - 8:06 pm: | |
That's exactly what I was thinking Joe. When I built my house a couple of years ago I paid strict attention to the vapour barrier. Seems to make a big difference in keeping the house cool in the summer and warm in the winter. Something else we added in the house was a humidistat and fan to ensure all excess moisture is exhausted.(as it is no longer leaking out through the walls) |
Ed Jewett (Kristinsgrandpa)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 14, 2006 - 9:42 pm: | |
I read a post on one of the boards, some time ago now, about putting Kool Seal elastomeric coating on the inside of the bus to seal it.
I don't know how effective it was but was curious about the outcome, never heard anything else about it.
I've seen several pics. where the interior was given a good coat of enamel to seal it.
Someone on here also had a post about putting down visquene between plywood floor layers for a vapor barrier and to stop squeeks. I thought that was a good idea.
We used to get spray cans of plastic at work but this was industrial stuff and would be cost prohibitive for a project this size.
Should the vapor barrier be between the insulation and the paneling, or between the insulation and the bus skin?
Ed |
Tim (Timkar)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 15, 2006 - 1:15 am: | |
Vapour Barrier should be between the insulation and the inside paneling.(Last thing before your interior finish) A good coat of enamel will provide a seal, but nothing like a layer of poly with the proper electrical pans, etc. As mentioned by Joe use acoustical sealant along the bottom joint and red tuck tape everywhere else there is a hole or a rip.
Tim |
Buswarrior (Buswarrior)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 16, 2006 - 8:10 pm: | |
Hello.
I am fascinated with this subject of sealing the insulation in the coach.
My question/concern about vapour barrier in a coach has been:
What is the effect of sealing the insulation between the coach skin on the outside, and the vapour barrier on the inner most layer before the interior finish panels?
At times, there is lots of humidity inside a coach, how reliably could a busnut prevent that humidity from entering the "sealed" space, and how would it get back out, or self dry?
How would we defend against some sort of eventual roof leak, typically around the air conditioners, wire access, roof vents, awning fasteners, dare I say loosening rivets....
Would our vapour barrier hide something we'd rather not have hidden?
What else might we be ignoring in an installation which doesn't have a "breathing side" to it?
happy coaching!
buswarrior |
Tom Caffrey (Pvcces)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 16, 2006 - 9:41 pm: | |
Yer gittin' serious, now. You've just answered why the bagged OEM insulation.
If you want to keep the insulation dry, and there is moisture exposure from either side, then a vapor barrier is going to be needed on both sides of the insulation.
I'm sure you can see the problems that this introduces.
If I were to get serious about accomplishing this, I would consider controlled ventilation of the insulation. This means that an opening on the bags would have to go to an insulated duct, and the duct would be opened to the coldest side as the weather changed.
In summer, when running air conditioning, you would want to open it to the indoors; in winter, to the outdoors.
For a comparable effect, refrigerators that used fiberglass vented the insulation to the inside of the refrigerator; if they didn't, the insulation became water logged and then froze.
Then, the heat from the warmest side is always driving the moisture out the coldest side. I've seen lots of refrigeration failures while living here.
When it was a walk-in freezer, and built on an on-grade slab that had no insulation under it, I've seen where the slab has been lifted up 6 inches and cracked all the way around the freezer.
That's a frost heave. And it's, no doubt, one of the reasons that industry has turned to closed cell foam.
For what it's worth.
Tom Caffrey PD4106-2576
Suncatcher
Ketchikan, Alaska |
joe padberg (Joemc7ab)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 24, 2006 - 11:48 pm: | |
Tom We have conundrum,can you visulize making our conversions more complicated by the addition of one more big switch that you have to remember to give it the required "crank" on April 12th and again on oct 16th and off course not a day sooner or later, in order to be "in season" ? This could lead to arguing for us having two coaches, each of course optimized for the right season No ? Lots of us have 2 cars, the nice one for summer and the not so nice for winter. Joe. |
Tom Caffrey (Pvcces)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 25, 2006 - 10:05 pm: | |
Joe, now you're talking about why people don't get serious about this. It's too much work.
You would be amused to see what we have to do for this problem with buildings in Alaska. For example, we need to seal all the power outlets from the inside to keep it from raining inside when there is a thaw.
The people who don't understand this suffer a lot of damage.
Tom Caffrey PD4106-2576
Suncatcher
Ketchikan, Alaska |
|