home insulation

[Tom K]

Greetings; I am redoing all the outside walls in my home. (in between my 2x4 outer walls is empty space. No insulation)

So I am yanking everything down (sheetrock is shot anyhow) and installing r-11 insulation.

I have been reading and wondering if its advisable to put clear plastic wrap (vapor barrior) between the sheetrock and wall/insulation????? (I know the plastic wrap has a specific name but I dont recall it.) Would that create a vapor problem? Would this be bad to use if using Kraft Paper R-11???

In addition to the interior walls, I shall be doing the outside ones too. What is the recommended/favored method? I am using vinyl siding on the exterior. Would you use vinyl->foam insulation-> house wrap(tyvec)???

Currently the house only has aluminum siding->tar paper ->

tongue and groove pine planks.

I am located in NY, weather here can be cold in the winter and real hot and humid in the summer. Most of the time cold though!

Thanx for any tips! Tom

[Walt Conner]

We were the first one in our area to put plastic between drywall and studs and ceiling joists. Did it 37 years ago, no problem and I think it has helped a lot with heating. Typar is one trade name for such a film maker. They make film for other purposes also including road beds over soft ground, quick temp landing strips for military.

Walt Conner

[New & Improved - N/F John]

One or the other, I've read you should not have to vapor barriers. Kraft paper acts as a vapor barrier.

[mark Ransley]

Fiberglass is apx 3,5 r per inch regular foamboard is 5 r per inch ......foil faced iso is 7.2 per inch . Use Iso ......

[Joseph Meehan]

You seem to doing the interior and exterior walls. It is a little unclear from what you wrote.

No vapor barrier and insulation is needed for interior walls. If you want improved sound reduction, use heavier or even better two thinner drywall.

No vapor barrier is needed if the insulation has Kraft paper, but personally I would add it. I would also not bother with the Kraft paper backed insulation.

House wrap on the outside is a good idea. It does two things. First it blocks air flow and it adds one additional water (not vapor) barrier under your siding. Both are good things. Do use housewrap however NOT plastic.

Note: if you are in a part of the word where it is very warm most of the year and you have air conditioning on most of the year, you need to make some adjustments to the usual arrangement.

[L. M. Rappaport]

On Fri, 24 Oct 2003 02:24:23 GMT, "Walt Conner" wrote (with possible editing):

Walt,

Doesn't typar go on the OUTSIDE of the insulation? I always thought typar permits water migration and as such belongs on the outside. Inside surfaces (beneath the sheetrock) are normally covered with plastic or kraft.

[Tom K]

I am doing both interior and exterior.

I am using fiberglass with kraft paper backing.

Would it be ok to use / benificial to use a plastic wrap over the kraft paper and under the sheetrock?

How about foam insulation (4x8 sheets) outside the house?

[Joseph Meehan]

You really don't need both plastic and Kraft. It would be overkill, except in special conditions.

I am not the one to comment on the foam.

[EJ]

You need moisture barrier on the _warm_ side of the wall. In cold climate with mostly heating season plastic sheeting is installed on the inside of the wall under the wallboard. In hot and humid climate with mostly cooling season plastic sheeting is installed on the outside of the wall under the plywood. In your climate with both heating and cooling seasons you probably shouldn't install a moisture barrier, but a moisture retardant such as kraft paper on the inside. Don't ever install plastic over paper. Paper will get moldy the next time you turn on the a/c.

You can use foam insulation on either side of the wall as long as it is not coated (= moisture barrier). Styrofoam or polyurethane will let moisture through and work as moisture retardant. Check your fire code carefully. In most locations foam insulation installed on the inside of the wall requires fire rated wall board. In any case it is dangerous stuff during a fire and can kill people with toxic fumes.

In addition to installing moisture barrier/retardant seal all gaps and openings inside walls, between floors and around windows and doors with sprayed foam and caulk.

EJ

[L. M. Rappaport]

On Fri, 24 Oct 2003 14:35:13 GMT, L. M. Rappaport wrote (with possible editing):

Actually, I think typar permits water vapor migration, but is essentially waterproof. Same thing in this case

[Tom K]

Great advice thanx....

Any thoughts about the home wrap in my climate?

Tom