lhort

My house is a 1950 uninsulated block ranch. Attic is well insulated and
vented. Windows are double paned.
We have a problem with moisture. Once it gets cold, we have heavy window
condensation, spots of mold will form in the corners of our plaster walls
and behind pictures, etc. In one room we took down the plaster to the bare
block and painted it with a sealer (dry lock?) put in 1/2 " styrofoam
insulation and then sheet rocked the walls. That did take care of the mold
on wall issue but not the condensation problem on the windows.

What should I do about this? This is what we are considering doing.
Installing furring strips over the stucco, then styrofoam insulation, then
wrapping the house with a vapor barrier/house wrap, then siding with vinyl
siding. Do you think this is the way to go? Would there be a problem
installing the vapor barrier on the exterior of the house? If not, would
there be a problem placing the barrier over the insulation rather than in
front of it? If the vapor barrier was installed on the stucco then the
nails for the furring strips would poke holes in the vapor barrier. The
house is cement block under the stucco is there another way? We don't want
to have to gut the interior of the whole house to fix this.
I would appreciate your expert advice, thank you in advance.

nealtw

Depending on where you live and the coditions there. Up here most of the moisture problems is from the inside air and the vapour bearier is to keep inside air from getting into the insulation. Normaly we would look at over the stove fan and bathroom fan not being run long enough to take moisture out. And welcome to the site.

Perry525

Put simply, you and your family produce water vapor by, cooking, washing, breathing, drying clothes, having indoor plants, animals,, sweating, children.

All this water vapor is held in the air, while it is warm.
Once you turn the heating down, or the outside temperature drops below dew point, that water vapor in the air heads for the coldest surface to conttdense.

You can see the condensation on the windows, this is good because you can wipe it up and it does no harm.

Elsewhere, you will have absorbent cold surfaces that will soak up the water vapor unnoticed.

Solutions, keep the air temperature up and the water vapor won't fall out.
Buy and use a de humidifier, this will provide a colder surface and most water vapor will head for it.
Do not cover the windows when it gets cold. Usually during the day the warm air circulating in the room keeps the window surface warm and the water vapor condenses somewhere else.
Open the windows, usually the air outside is colder and drier and the water vapor will move outside.
Fit treble or quadruple glazed windows, this again will raise the window surface temperature and move the condensation elsewhere.
Fit and use a ventilation system with a built in heat exchanger.
Use a exhaust fan in the bathroom when washing and another when cooking in the kitchen.
Exhaust fans with heat exchangers are best, ones with air tight covers as well, are better