Insulation question

[Alexander Galkin]

I am going to replace of insulation in my house walls. I checked today R-13 insulation at local HomeDepot. There are two kinds of R-13 insulation from the same manufacturer. The first type is R-13 batts completely encapsulated into plastic film. I believe the plastic acts as vapor barrier and no additional vapor barrier is needed. They are sold as continues roll 15" wide and costs about 26 c / sqft. Another type is Kraft-faced batts also 15" wide and 8' long, so they are already precut and no additional cuts are necessary. They are sold in big packs, 8 rolls in each pack. Cost is about

35 c / sqft. I wonder why the first type is cheaper. Since it is fully encapsulated and sold in much smaller pack it should be more expensive. Am I missing something here? I think the first one is much easier to work with as it does not itch. Which type is best for wall insulation?

[m Ransley]

The plastic is not a vapor barrier , it is so you dont get glassed. Are you tearing down walls? Rock wool or cellulose can be blown in holes you cut and repair , cheaper and easier. A vapor barrier must be continous, vapor will pass where the insulation touches the wood.

[Joseph Meehan]

I just have to ask. Why?

Sorry. That plastic is just to protect your hands from the fiberglass. You still need a vapor barier.

They both work, but the non Kraft type will require a vapor barrier. I personally think a plastic film barrier is better than the Kraft version, since most of the time you end up with gaps when using Kraft.

[Alexander Galkin]

Yes, I am tearing down outside walls as I install new windows and have to enlarge rough windows openings. Anyway even if encapsulated plastic is not a vapor barrier it makes much more comfortable to work with insulation as you practically don't need to wear protective clothes as insulation does not itch. The only concern I currently have is that regular Kraft faced insulation batts have paper shoulders to staple batts to studs while encapsulated ones do not and they are probably just laid between studs. Does this mean that insulation is not completely tight as unstapled batts can slider down over the time?

[JerryMouse]

For wussies:

1. One pair heavy athletic socks.
2. In tip of each sock, cut one large hole and one small hole.
3. Fingers go in large hole, thumb in small hole.
4. Rest of sock up the arm.

No itch.

[Robert Barr]

I installed a boatload of that Dow-Corning insulation, unfaced, and I had no trouble at all with the typical fiberglass itch / irritation. It wasn't a problem. I was pretty surprised, actually.

[m Ransley]

The vapor barrier should be on the inside or moisture can be trapped in the wall,

[Robert Barr]

Oops. Meant Johns-Manville.