Friday, November 16, 2012

Isolation in your van / car


Keeping warm in your car is something that I feel is important, this is usually no big problem in the summer, but in the Swedish Winter, it gets cold...

Laren Corie (http://groups.yahoo.com/neo/groups/VanDwellers/conversations/messages/170761):
"Never.... Never have two vapor barriers
(the plastic and the metal of the body) with
a gap between. What that will do, is to trap
moisture between (there is no such thing as
a vapor barrier that does not leak. So, when
you have a vapor barrier on one side (the
metal of the body) the other side needs to
be able to breathe moisture. In this case it
needs to be able to dry to the interior. A
vapor barrier would stop that from happening
and your foam rubber (very expensive insulation)
would become a wonderful medium for mold
spores to grow on/in.

So, you should make you walls air tight, but
not totally impermeable to moisture diffusion,
If you drive your van regularly, then drying is
not difficult. Vehicles are very leaky while
moving, and the dash heater takes the dry
Winter air, and heats it further to make it
even drier. Just blast the heater when you
drive (this is all during the heating season)
and everything, including the walls should
dry out, if you allow that to happen, by not
putting in a vapor barrier. We used to think
vapor barriers were a good idea for houses
too. But, time and building science has shown
us the folly in our earlier thoughts."


This is what Laren Corie recommends as insulation:
Isocyanurate
However I don´t know where I can get a handle on it here in Sweden
He says:
"Only XPS (extruded polystrene) squeaks. Use isocyanurate, the yellowish stuff with the foil face. EPS (expanded polystrene) does not usually squeak, but it falls apart." -Laren Corie


I did some searching (on the net) and found more on the name: Polyisocyanurate (Polyiso). Polyisocyanurat (PIR) isolering in Swedish

EPS and XPS foams are called and are thermoplastic foams, while Polyisocyanurate is a thermoset foam.

EPS and XPS will melt at a certain temperature while Polyisocyanurate can take heat better. The Polyisocyanurate foams are also generally more resistant to solvents and chemicals.


In general, EPS foam has the lowest R-value with XPS being slightly more efficient, and with Polyisocyanurate having the best R-value per cm.

Another simple solution to quickly isolate is using Thermoreflex (sweden name). I think it is callad Reflectix in america. (Reflekterande isolering, med bubbelplast)

This is a good guide to read more:
http://www.buildingscience.com/documents/guides-and-manuals/gm-guide-insulating-sheathing

Or if you prefer swedish, a report from Skanska:
http://www.sbuf.se/ProjectArea/Documents/ProjectDocuments/711DBF18-F83A-4F42-95DC-7C0BD0ADFE96%5CFinalReport%5CSBUF%2012315%20Slutrapport%20Inventerning%20och%20utv%E4rdering%20av%20h%F6gpresterande%20isolering.pdf

Here are some other tips I found on some forums:

"Bubble wrap is a good insulator.  Use with small bubbles = layer it 6 times.  Attach with duct tape.  It worked fantastic for me."

Than another tip came from "Big Blue":

"Ive been to several stores and read tons of info on insulation.  From all that I gathered:
1.       Spray foam is toxic and gives off gasses regularly
  1. Anything with aluminum of any kind on steel with an electrical current induced with causes rust.  (your battery is grounded through the chasses)
  2. Have a vapor barrier."

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