Which is better stucco or siding

How should I insulate the walls in a stucco house?

I suppose you want to insulate the walls. Houses of this year often had no insulation between the wall posts. The easiest way to insulate them without destroying the stucco or drywall is to drill holes through one or the other at the top of the tunnel bay and blow in the cellulose insulation.

If you do, however, you will affect the wall's ability to dry when it gets wet, as less heat and less air will pass through these empty voids - both of which will promote drying. This is not a huge problem with a modern wall, where the stucco is separated from the wood with tar paper or house wrapping. In an old house like yours, however, the stucco was often applied to wooden slats without tar paper separating it from the wood. In fact, in many cases, there was no sheathing at all! They simply nailed wooden slats to the studs and plastered them.

In such a wall, adding blown cellulose insulation can be a problem if the stucco gets wet because it cannot dry as easily and cellulose itself can hold water. The risk of this approach depends on the climate and construction. If your home is in rainy San Francisco, it's riskier than Campbell or San Jose. If your house has no jacketing and / or tar paper under the stucco, it is riskier than if it is.

In such borderline cases, if you really want to insulate, the prudent approach is to remove all of the stucco, put some non-woven insulation (fiberglass or mineral wool) between the exposed studs, then put plywood sheathing, wrap the house in tar paper or house wrap, 1+ Apply inches of hard foam or mineral wool insulation over it, then nail 1x3 strips of fur over it, and then apply new stucco or siding over the fur strips. This would of course be the most expensive option, but it would result in a very well insulated wall and no risk of mold or rot.


The other problem I've seen with wall blowing is the return on investment. For a medium-sized home, look for someone to do the job for 3-4,000, and in such a temperate climate you will only see $ 100-200 savings on heating bills over the winter.


I advise people to stay away from foam work for houses like this ... wouldn't even think of using blown cellulose. Heat readings after spending tons of money and opening hundreds of holes in a house are not much better than previous readings (and a lot of the foams are toxic).


I don't prefer foam either, but rigid mineral wool could work instead. Even so, I agree with both of you that the cost-effectiveness of such projects in the region of the poster is questionable.


No "zero risk". Also, your plan calls for expanding window frames, a large task that can easily lead to mold or rot.