I wanted to know if anyone had any experiences using the bubble wrap w/ the double sided radiant barrier.

I had a weird experience thanks to a fire pit, my Brother-in-Law, and a few beers.  My Brother-in-Law made a make shift pot holder looking glove and held it about 8" away from a pile of extremely hot embers.  After nearly a minute the glove started to smoke because the exterior nearest the fire was starting to melt.  Despite this, he said the inside never got that hot.

What I am figuring is that, if this material works this well with such extreme temperatures, why wouldn't it be useful in a knee wall area?  It would be a lot easier to install than rigid foam board and much easier to squeeze through a small access hole.

 

What do you guys think?  Do you have experience using this material? (Keep in mind I live in Atlanta, GA, not New England).  Thanks!

Tags: Insulation, bubble, heat, knee, transfer, walls, wrap

Views: 643

Reply to This

Replies to This Discussion

Remember, a radiant barrier only reflects radiant heat.  The fire test your brother in law did was the ideal test for that material, since essentially all the heat was radiant, but in an attic situation that's not the case.  For the radiant barrier to work, there has to be an air space between the barrier and any other objects (to rule out conduction), and its surface has to remain clean and shiny (no dust collection).  So would it help in a kneewall area?  Maybe a little, but not as a replacement for insulation.
I get your point, but I am talking about using it in addition to the existing insulation.  The most common treatment here for knee wall problems is to seal the penetrations from the attic side of the wall, push the batts (usually R-13 here) back into place and then attach Thermax sheathing with a radiant barrier to the studs over the batts and seal the seams. Sometimes the construction, access, and penetrations make using a rigid foam board product very difficult to use. The bubble wrap radiant barrier seems to be a good alternative.

Installed in that location -- over the fiberglass batts -- I would be concerned about condensation on the bottom surface wicking into the fiberglass and creating mold habitat.  I'd also be concerned that dust would accumulate on the top surface and make the radiant properties useless. 

Has this stuff been in use long enough to be able to check in on an installation that's 5 or 10 years old to see how it's holding up?

Jon,

 

  I'm guessing that the foil/bubble wrap will provide a real good air seal if installed properly (like every other air seal material) but will be much more costly than poly wrap and not provide anywhere near the insulation of EPS or XPS board.  I've seen no independent testing of these products to verify their claimed "R" values.  Knee walls are always a pain; almost makes you want to rip out the walls to re-do everything.

You can say that again.
We see Reflectix used behind knee walls all the time.  It is the air barrier to prevent windwashing, and meets code for fiberglass batt covering.

You should put a link to Reflectix in your post. I haven't heard of it.

RSS

Home Energy Pros

Home Energy Pros was founded by the developers of Home Energy Saver Pro (sponsored by the U.S. Department of Energy,) and brought to you in partnership with Home Energy magazine.

Latest Activity

Susan E. Buchan posted an event

EEBA Excellence in Building Conference at Doubletree Union Station Hotel

September 23, 2014 at 8am to September 25, 2014 at 2pm
9 minutes ago
Rem Husted replied to Andy Gostisha's discussion Disguising Ductless Heat Pump Units
"I think most consumers wouldn't want a big box called a refrigerator or a stove or…"
26 minutes ago
Scott Katznelson replied to Scott Katznelson's discussion Database of zip code or county by climate zone
"You know those maps you can find for energy code climate zone specific reference.  That's…"
1 hour ago
JEFFREY M HUGO, CBO replied to Richard Beyer's discussion Sprinkler Mandate Debated.. What do you think should be done?
"Fire sprinklers operate when the fires are small. Typically it only takes approx 20 gallons per…"
1 hour ago
Scott Katznelson replied to Scott Katznelson's discussion Database of zip code or county by climate zone
"Thanks.  That's the best source I've yet found, and maybe the best that's out…"
1 hour ago
Diane Chojnowski replied to Scott Katznelson's discussion Database of zip code or county by climate zone
"I posted the question on HEP's facebook page and Bill Spohn commented: Try…"
2 hours ago
Profile IconKevin Jordan, Hannah Strong, Rich Snyder and 1 more joined Home Energy Pros
20 hours ago
EnergyLogic Academy posted events
21 hours ago

© 2014   Created by Lawrence Berkeley National Laboratory.

Badges  |  Report an Issue  |  Terms of Service