Insulating basement windows - does this look right?

deflux

So I'm working in the basement and noticed that I can see the exterior brick from below the glass block windows. Should there be some sort of insulation up there? To me it seems too open, but I'm certainly no expert. (Photo attached).

Thanks!

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gregzoll

You could stuff some unfaced insulation up along the space, but without knowing what is exactly up there, without shining a light while using a mirror, you do not know how far the cavity goes up.

deflux

Hey Greg,
My concern was cold air just pouring into the basement through that opening. In the room right above that window, the wall is not cold, but it just seemed to be a gap that I didn't like the looks of. I'll get some unfaced insulation and push it in there. Would it be better to put it in a plastic bag too? I thought I read that helps with the insulating effect.

Thanks!

gregzoll

The plastic would act like a vapor barrier. If you can spray foam, that would be better, but stuffing loosely regular unfaced batts should work.

Jim F

Moisture intrusion is a greater concern than heat loss. If heat loss is not a major concern, a little ventilation in the basement is a good thing. Many basements have humidity or radon issuse. I would rather pay a little more for heat than have radon in my house. I don't worry nearly as much about the little gaps and cracks as some do.