Will adding insulation to the exterior walls help get rid of mold on the inside?
The house was built around 1958. It has aluminum siding. It has little to no insulation in the walls. About 15 years ago I tried to get sprayed in insulation put in the walls. The company told me they couldn't because the 2x4s were the wrong way and the foam didn't have room to expand. The interior walls that touch the outside keep getting mold on them. I keep cleaning with bleach, but it keeps coming back. Someone told me if take of the siding, put insulation, and put new siding that the mold would go away. Is that true? If not, what would be the best way to fix this problem? Over the years it is getting worse.
Insulating the exterior of older homes is the best method if possible, but must be done carefully to not trap moisture in walls and ensure that they can dry. Existing walls in homes situated in cold climates most often have an interior vapor barrier, and walls should never have 2 vapor barriers. For that reason, it is important to know the assembly of the wall and to choose the right materials so walls can stay dry. Here is a page that explains it -
The best way to insulate walls from the exterior of older homes
In your case since you have no insulation at all it really sounds like exterior insulation is the answer, and yes, that would solve the problem of mold. May I ask where you live or at least what climate zone you live in, that helps determine a sensible amount of insulation as well as way to do it safely. Climate has a lot to do with choosing the right wall assembly and amount of insulation for the best return on your investment. From that I mean – going through the effort of removing siding for a home renovation and only installing 1 inch of insulation on the exterior can be a lost opportunity, since installing 2,3, or 4 inches doesn’t require much more effort but can make a big difference in energy savings. Also very important, is knowing how a rigid insulation handles moisture to know if it’s the right product. Mineral wool insulation for example, lets moisture pass right through it, but rigid foam insulation can act as a vapor barrier.
live near cleveland oh.
Code for Cleveland seems to be R20 for walls. Typically we recommend insulating more than what code requires as that is a minimum, but I'll leave that for you to decide, can you go as thick as 4 inches? As mentioned, if you're going to the effort and cost of removing all the siding I'd want to take advantage of it and not do just one inch.
In your case since you have no insulation at all it's safe to put foam on the outside, and anything over 2 inches will be a vapor barrier, which is fine since you currently have no insulation at all. 2 inches would be good, 3, 4, even 5 inches would be better if you can, but, do what you can.