I put new windows in my house and now that it's cold I have condensation on the inside. What's wrong?

Question

I was as thourough as I could be when I sealed up the outside with expanding foam. Is it also necessary to seal up the inside with caulk?

I guess I should have mentioned I live in Alaska.

Answer 1

Expanding foam is not made to be exposed to the elements... you should plan on caulking outside at some future date.

Right now... your problem is the humidity in the home... simple fix... buy a dehumidifier for 20 bucks and let it run.

If your home has a crawlspace then it would help to put a vapor barrier under the home. If a basement, then plan on putting a dehumidifier down there too... Its amazing how much moisture will wick up thru concrete.

Back to the expanding foam... I use the DAP white foam... it expands to 75% of its volume immediately (and its easier to clean up after)... GREAT STUFF continues to expand for up to an hour.... which means it is easy to get too much in an enclosed space, like next to window frames, and can cause bowing of the frame. I like to use batt insulation where possible in the wall cavity around the window, and insulating foam to help form a wind barrier right around the window, but I do not fill the space with expanding foam... just creates too much trouble with the windows. I like to caulk the face surface of the wall around the window opening, after I've dry fitted the window... once it's caulked then I set the window in place and secure it. If you used expanding foam instead of caulk for this, then you can expect some leaks in the future, as the foam breaks down.

Good Luck

Answer 2

I have seen your problem first hand myself in an older mobile home I bought to remodel. The windows were very loose and I bought weatherstripping tape to seal them until I could replace them. I was outside on a cold day and watched them cloud up as I sealed them.
Everyone is probably correct with the answer about excess humidity...problem is: therein may lie your problem. Before your house was so loose that the normally experienced air exchange was enough to keep the excess humidity at bay but now that you have slowed the air infiltration you may need to look into exhaust fans in your baths and kitchen.
You should also look at a way for some air to enter your home in a controlled manner as with a fresh air intake on your HAVC system. The one marketed by AprilAire is highly rated in my area.

Answer 3

You don't say where you live, but it sounds like the humidity in your house is too high. Once you start heating the humidity will drop. You can also open the windows when it is warm and sunny, that will lower the humidity.
The good news is you sound like you are pretty well insulated.