Sealing all the cracks?

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WestBentley

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As I may have mentioned, we pulled down all the trim in our house, including around the windows. Aaron has noticed some slight air leaks and wanted to fill them in with "Great Stuff" foam to make things more air tight. I was under the impression that you wouldn't actually want things to be "air tight" in a house (similar to when that stupid idea of duct taping your house shut came about). He filled in spots where you could actually feel a breeze/draft but I was hesitant to let him fill in everywhere and end up with not enough air getting in the house.

Does anyone know the guidelines on this? I assume there is a minor about of air getting in via the window sills/sashes, although they are thermal pane.
 
Most of the time you can't stop the exchange air because it will come from places you don't expect as well as opening doors. Usually people try to stop the leaks and then if they have trouble with stale air, they work on some kind of controlled air exchange system.
 
So you don't think there would be a problem with sealing the leaks around the edge of the window frames, as long as the sill/windows themselves and doors in the house are letting air in? We have plenty of windows, 2 doors and a sliding glass patio door, so maybe we'll get enough fresh air anyways?
 
It is almost impossible to caulk a house enough to prevent air infiltration. I think it was in the 80s a lady had her house wrapped in polyethelene; it sealed it so tight that her breathing and heating systme burned up all the oxygen in the house. She went to sleep and didn't wake up.
In our area the coldest winds come from the northwest in the winter; if your prevailing winds are different the following test will work out different.
A good test of air infiltration is to check the temperature in the northwest corner of the house and in the southeast corner. If you have 5 degrees difference (the northwest being the cooler) then you have air infiltration. The wind is blowing right through your house.
Glenn
 
The oly house I had that was even remotely airtight was a superinsulated home I owned in the 80's with 12" thick walls. It did have a fresh air exchange system but I didn't think it was really necessary...
 
Good post FHI, we always reccomend Minimal Expanding Foam for windows and doors as well, so you do not warp your opening.
 
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