Anybody got a brand name for this stuff or know of a reliable west
coast (USA) retailer who sells it?
I've looked at our local Home Depot and Lowe's outlets and found only
the 1/2" thick variety with the poly sheathing which I'm told is meant
only for waterproofing basements.
~Pete
There are two types and they are effectively the same. The pink
variaty is made by Owens Corning. Owens Corning also makes 'pink' fiber
glass insulation as well. Other companies make natural color
(yellowish) fiber glass insulation. (Pink is Owens Corning's trademark
color: think Pink Panther, who is their spokescartoon.) The blue
colored foam is made by various other companies (Dow comes to mind as
one). Both colors are same dense insulation foam. If it is not
available at Home Depot or Lowe's, it should be available at
'conventual' lumber yards. I'm guessing you are in a 'warm' area,
where insulation against winter cold is not a major issue, which might
be an issue in terms of what is stocked locally.
Google Image Search:
formatting link
Pink Foam (Owens Corning):
formatting link
Blue Foam (Dow):
formatting link
Here is some additional info:
formatting link
What you want is the Extruded polystyrene (XPS), which comes in Pink
(Owens Corning) or blue (Dow).
Yes, but, lots of do-it-yourselfers in warm areas don't always get it,
so Home Depot, et. al. might not stock it. Which is why I suggested a
lumberyard. Also, the foam is often used around masonary foundations
which may or may not be typical in some areas, which again is a local
'preference' issue and might have to do with local geology issues -- eg
water tables, soil / ground formation issues, etc. Also insulating
*basements* is a different issue from insulating above ground areas.
Above ground, spun glass insulation or blown in insulation might be
more typical for example.
(The availablity of foam insulation in certain places has come up here
before.)
Those are _minimum_ R-values based on cheap energy. They ignore the real
increase in energy prices. IOW, they are too low. My rule of thumb is:
double the minimum recommended R value. That's what I did when we built
our house 31 years ago. I figure I recovered the cost of additional
insulation within two years. And since then recommended minimums have
increased, so that I now have a house insulated to the current minimum
standards.
Here's updated information on recommended R-values:
Mark Mathu on Tue, 10 Apr 2012 21:38:04 -0500 typed
in rec.models.railroad the following:
Hot or cold weather - I want the heat to stay on one side of the
wall. Inside in the winter, outside in the summer.
True, but the effectiveness of a given R-value is a function of the
DIFFERENCE in temperature between the two zones. The rate that heat
moves from a hot zone to a cold zone is proportional to the SQUARE of
their difference in temperature. If you double the difference in temperature,
you need FOUR times the R-value to heat or cool the space you want to
control with a similar amount of energy (roughly speaking).
If you want to keep a place at 72F/22C when it is 100F/38C outside, there
is a temperature differential of 28F/16C to insulate against.
That is a far cry different from needing to keep a place at 70F/21C when
it is 20F/-7C outside. This is a 50F/28C differential.
True, but insulation is cheap. Question: where do you put discretionary
dollars when building or renovating a house? Granite counter top? Or
higher R-value insulation? The incremental cost of higher R-value is a
good deal less than the square of the R-value difference. IOW, it's very
low when building, and still quite low when re-siding or re-roofing. So
you have more R-value than you "need"? Ok, but so what? Every little bit
helps. In the long run, you'll save loadsadough. Keep in mind that the
price of energy will go up. It will dip down now and then, but the trend
is up and up and up.
And it's not just R-value that counts. So does colour. Data-point: When
we had to replace the dark brown shingles, we went to the palest grey we
could find. Reduced the ambient temp in the upstairs rooms by about
5C/9F. Amazing. ;-) (We have a cathedral ceilings, probably the worst
type for heat retention/rejection).
Anecdotal evidence from people who've built houses using odd-ball
technology, such as 2ft thick straw bales, impregnated with cement
slurry for fire resistance: heating/cooling costs on the order of 10% or
less that of a conventional house.
Final observation: we tend to fixate on purchase price (PP), not total
cost of ownership (TCO). Printer mfrs (for example) exploit this bias.
HTH,
Wolf K.
Calvin Henry-Cotnam on Tue, 17 Apr
2012 09:42:29 -0400 typed >>
Or when it is 110/40 in the shade "and a good thing we're not in
the shade." I use to wonder about wool robes in the desert, till I
realized that 98.6 (36.8) inside - 120 plus outside, wool makes for a
wonderful insulator.
True. And the outside temp is lethal.
I totally agree that added R-value is great, and I have done this in
constructing my own home.
Of course, there is a law of diminishing returns at play here - the
first "R" has the most effect and each additional "R" added provides
slightly less effect than the previous one. There is also the matter
of some situations, such as within walls, have a maximum capacity
unless additional framing (with it's costs) is added, or unless a
material with a higher R-value per thickness unit is used (the foam
board of this discussion has about 5 per inch, while fiberglass has
about 3.6 and rockwool has about 4).
I was merely pointing out why the standards vary from one location to
the next, which was an early question on this topic.
And in turn directly relates to what sorts of isulation is availble in
various locations. Getting 2" foam isulation from the local Home Depot
is trivial here is New England, but is likely to be harder in warmer
areas, where 2" foam isulation *might* be considered 'overkill' or
where local construction practices would not use foam isulation at all.
Foam isulation is most *commonly* used over concrete basement walls
(either inside or outside). In parts of the country where concrete
basements are uncommon (either because high water tables (Florida)
preclude basements or because of local geology prevents digging cellar
holes, etc.), *foam* isulation might be harder to get.
At the start of this thread, the OP was having a hard time finding foam
isulation in a useful thickness and noted that it was not available at
the local Home Depot and wanted to know about different types and where
he might get some.
I live in Redlands, MIke -about 65 miles east of lovely downtown
Burbank- and I've discovered that I can special order the pink stuff
from Home Despot, so the guys in our club are working up a collective
order right now.
Thanx for the thought.
~Pete
That is more of a difference than you suggest.
Sure, the peak difference between 120 and 75 is 45F, while my example was
50F. However, I don't know of too many cold climate zones where the
difference changes by 25F as "120 dropping to mid 90s at night" does.
Not that such swings never exist, but few places that are 20F at night
rise to the mid-40s on any regular basis. Colder climates tend to have
greater SUSTAINED differences than hotter climates.
Such changes are common in desert areas. Many places in CA, AZ, NM, NV,
UT, ... have such changes.
We used to go to Hemet CA for the winter months. Go to bed with the AC
(or evaporative cooler) running and wake up under 2 blankets :-).
PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.