Proper way to insulate a basement
I’m sure the answer is available in a previous post, but I could not find anything with the search function that addresses my question (surely user fault 🙂
I’m building a house in the Seattle area. It has a daylight basement (3 sides underground, one open, with windows), on a sloiped lot. The 3 undergound walls are concrete, sprayed externally with a silvery-looking goop (sorry, that’s as technical I can get on that), and we added a Delta Drain membrane (dimpled plastic sheet with landscape fabric, to help drain excess water to the pipes on the bottom of the walls/footings). The floor is a poured slab on visqueen, with foam insulation along the exterior edges.
The framer built 2×4 walls next to the concrete (bottom plate is treated wood, studs are plain wood). The insulation company has used standard unfaced fiberbatt insulation (yeah, I know that there are better choices, but the weather in Seattle is very mild and adding insulation costs more than the savings, not to mention I had a hard time finding anybody familiar with anything but fiberbatt, as it’s the most common method up here), with no vapor barrier of any kind.
Do I need any kinf of vapor barrier, or unfaced batts are the way to go, in this case? I’m trying to understand vapor barriers, and I know that in some cases they actually cause more harm than good
Thanks in advance, Rob
Replies
Bump this a few times to get Boss Hog to tell you about his spec house from hell. He probably has the best type insulation (4" of styrofoam on the outside of the wall as I recall, he can give details).
I actually did read a post on the spec house from hell... a bit too close to home to laugh about it, though :-)
Any suggestion? Even a link to a past thread would help. To vapor barrier or not to vapor barrier, this is the question...
Thanks!
Take a look at the resources over at Building Science Corporation. Lots of very good info on how to keep your basements dry and mold-free.
I also recommend the "For Pros by Pros" series by Taunton Press on Foundations. Lots of good info in there as well.