I'm beginning to enjoy this thread immensely!

When bringing a basement into the conditioned area it's always paramount that ALL moisture issues be ELIMINATED first. If it's not possible to properly deal with all outside moisture then one should remove the basement from the equation with extreme prejudice! Just fill it in! The condensation issue isn't unique to basements. In fact, the sheathing of a house here in NE will get much colder than any basement wall below grade ever will. So the dew point calcs are very similar.

Good thread here, much to ponder.

Don't want to change the direction, so if you'll bear with me...

On a related note, when I was running my test heat pump last winter, I was amazed by the amount of water that was condensing on the pipes that brought loop water into the basement, and that took the chilled loop water (that had been through the evaporator heat exchanger) and sent it back out to the loop.

Constantly condensing water, puddling on the floor, I couldn't figure out where it was coming from for quite a while.


My fix was to put foam pipe insulation on the pipe and to tie it on tight with nylon cable ties, so that high humidity basement air was not coming in contact with the cooler loop water, and especially, the chilled loop water.

In this same manner, it would seem that a gapless insulation application, like spray-on foam would work wonders in a basement. That way, high humidity basement air could not contact walls, and not condensation.

What do you guys think?

-AC_Hacker

Indeed. Why is it that we want to live in caves?

Closer to the Earth? It's peaceful down there? I don't know but I love to be below grade. Building a basement that isn't finished in a new house costs a lot more than building an extra story. Even a third story. But a finished basement is worth it to me. Maybe I'm part troglodyte on my Scottish side?

AC_Hacker, You make very interesting points which are thought and conversation provoking. Unfortunately I don't have a free minute to think about them much less respond as it's past my bedtime and I've already turned into a pumpkin. I will respond soon though. Thanks for participating all!

I sleep, watch TV and use my computer in the basemen.

Advantage: Quiet
Easy to keep cool in the Summer ( Like 1/2 tons per 1000 SF).

If my house didn't have a basement, both my heat load and cooling loads would be much higher. With having part of the house buried, it allows there to be less exposure to the sun, a geothermal cooling blanket in the summer and a space warmer than the outside in the winter. It was extremely helpful this summer, I could let the upstairs get to 85 degrees and then I could sleep on the level above the basement level at 76 while it was in the mid 80's outside and sunny. In the winter the house is getting geothermal heat when I'm not heating it beyond the soil temperature. Call me crazy but my November methane gas heating bill wasn't even $20 and I'm in Minnesota. Very little infiltration now with all of the retrofitting so humidity levels aren't really dropping even though I stopped boiling water for pasta and vent my bathroom until the mirror is clear after I take a shower. More heating with more temperature, pressure differential, and furnace make-up air would increase the fuel usage quite a lot. I'm comfy in the cold though. I'd imagine if I lived in the southern half of the country I'd probably never turn on the heat I was reading stories on hvac-talk where people in Virginia have estimated heating loads for a house smaller than mine having them install a furnace larger than the one I have in my much colder climate that came with my house and is over double the size it needs to be post-retrofit(or third the input if I put a 95% in).

I'm tempted to just insulate half the wall and leave the bottom half exposed (ground temp should be 50F even during the coldest time of year). I'm really poor right now (!) so the cheaper the option, the better at this point. I also don't want to create a mold factory (i would imagine leaving the bottom half exposed would allow moisture to move through the concrete without get trapped).

Not sure if I will finish the basement, so using something like polyiso might make sense for now.

Lot of basement insulation horror stories, don't want to create another one.

Outsulate. It's the best option. Use XPS and make sure it's at least 2' below grade. Then screw chicken wire to it and apply some stucco or something to about 5" below grade.

That is probably the best way to do it, but I've always been worried about termites. This past summer I pulled up some landscaping timbers out in the yard and the bottom was basically hollow! There use to be an old tree before I moved in and one day I was digging out the stump (that was rotten) and it was full of them.

Get the kind which is treated with borate specifically to prevent termite infestation and cap the boards with copper flashing so if they do get in there they can't get into the wooden parts of the house.