Potential Insulation Problem?

[TheWalkman]

I'm renovating an old (1920's) stucco house and want to insulate the existing walls.

The walls currently have no insulation i.e. they are plaster =>open studs => wood sheathing => metal lathing and stucco. There is no tar paper or vapor barrier between the existing wood sheathing and the stucco.

If I were to use blown cellulose in the existing stud space will this lead to moisture issues/ rot in the studs? Would the high tech foam insulation work better? Are there other types of insulation designed for applications such as this?

Thanks

[t527ed]

i guess it would depend on where you are at as far as a moisture problem goes. around here i see insulation companies pumping the blown in stuff in the outside walls all of the time and have never heard of a problem.


shooting the foam into a closed cavity could get scary..........:cool:

[hvacker]

Stucco does wick moisture. I don't know what might have been used for sheathing that long ago. My home is stucco but was sheathed before the stucco was applied.
In my home a former garage was made into a studio and celluose was blown in helping a lot. With celluose their is no guaranty of filling the void completly due to wiring or firestops in the way.

I am sure foam would be better in every way but cost and the possibility of chemical reaction for some people.
In Santa Fe a house was foamed on the outside walls and then surfaced with synthetic stucco. Sounded like $$ but the structure was insured. What was nice about this solution was the foam could be applied as thick as wanted. This would probably be my choice but if your home has nice flat application of stucco outside foam won't give you that look but rather like a lot of ups and downs.

[TheWalkman]

i guess it would depend on where you are at as far as a moisture problem goes. around here i see insulation companies pumping the blown in stuff in the outside walls all of the time and have never heard of a problem.


shooting the foam into a closed cavity could get scary..........:cool:

I'm in Virginia.

The existing structure, which I want to insulate, has no water resistant barrier between the wood sheathing and the stucco. Since stucco is permeable to water, my concern is that if the cellulose insulation were to get wet - from condensation or leakage- it would tend to stay wet for a long period of time, potentially creating a rot or mold issue.

[hvacker]

I'm in Virginia.

The existing structure, which I want to insulate, has no water resistant barrier between the wood sheathing and the stucco. Since stucco is permeable to water, my concern is that if the cellulose insulation were to get wet - from condensation or leakage- it would tend to stay wet for a long period of time, potentially creating a rot or mold issue.


If it hasn't already.

[TheWalkman]

If it hasn't already.

Actually, where we've gone into the existing walls, they seem fine.

My guess is, that building sciences in the twenties (right...) designed such that if any moisture invaded the stud space, there is enough air between the walls for it to evaporate and then diffuse back through the stucco in the form of a vapor. Therefore, the wood never stays damp enough to rot or mold badly (unless, perhaps, there is a crack which would lead to actaul flooding in the space.)

This is really the concern I have; if moisture is trapped/ absorbed by the cellulose, it will evaporate very, very slowly and possibly lead to the rot/ mold.

[Catpower]

My folks had foam blown into their old farm house in NW Iowa back in the seventies, it worked good, made a world of differance, if I had to do it I would lean towards foam, as you have stated the problems with cellulose, it will also settle as well just from gravity.

[Wheelbaron]

Certanteed makes a blown in fiberglass, but it requires larger holes. If you are gutting inside I would use bat insulation. Spray in foam works too, but a lot more $. Call a local insulation contractor, get their ideas.