I would insulate the basement ceiling first.

If you do the walls you have to be sure there are no moisture problems first.

Insulating a basement wall is a little tricky. There are some deciding factors which need to be addressed. First if the basement has chronic moisture problems, interior insulation should not be installed. It would be best to insulate the outside, and try to correct the moisture problem at the same time. This is very expensive to do. If the foundation walls are wet or damp frequently, insulating could trap this moisture and cause frost damage, as the walls will be significantly colder due to the insulation.

If you fell that moisture is not a problem it would be wise to frame out the walls with studs, and install batt-type insulation. A moisture barrier should be added against the foundation walls, and a air/vapor barrier should be added on the warm side of the insulation.

I'd insulate the ceiling of the basement first too.

Owens Corning has a basement finishing system if you want to hit the walls later...

http://www.owenscorning.com/around/bfs/index.asp?JustSawFlash=true

Thanks all. I'm just not sure it makes sense to insulate the ceiling in the basement as it's part of the living area. Is that the correct thinking?

Is the ceiling finished or unfinished?

Don't insulate the ceiling if you live in the basement.

If you have never had moisture problems, you should be safe to insulate the walls. Moisture problems are the main reason not to do it. Assuming that you do not have a stone foundation, it is generally a matter of cost and esthetics whether to insulate inside or outside the foundation.

The old way was just to insulate above grade, but more modern installations insulate below grade as well. The ground maintains a temperature much lower than you would be comfortable living with, so it will suck the warmth out of a basement faster when it is uninsulated.

You might also want to insulate the floor as well. That requires special products made for the floor.

The ceiling is unfinished. Most of the basement is unfinished, but we do spend time in there--hobbies, laundry, small finished office, 1st floor powder room is actually half-way down the basement stairs, etc.

We sort of have moisture problems, though they haven't really been problematic. No moisture coming through the foundation, that we can tell. We have some other moisture problems, like an annual plumbing backup (there are drains on the floor) which we've managed to prevent lately but isn't truly fixed. And once the city sewer backed up in there (that's exceptionally gross). So we do want to keep the floor clean, concrete, and bleachable for those special occasions when we feel the urge to sterilize the floor.

It does get humid down there, not that you'd feel it. Very cool in summers, but on some days water will condense on the cold water pipes.

It would make the most sense to just insulate the basement ceiling and just treat the basement as outside the heating/cooling "envelope", but the arrangement of stairs and doors (and halfbath) don't really permit that--I can't block off the stairs effectively.

Lots of stuff to consider--thanks for the ideas. I like to think that my next house will be new and energy efficient and have a solar roof, but that's what I thought before I bought this one. New homes are so boring.

Fori- It sounds like you do have a lot to consider. Now here is some more; They have flood stoppers you can put in the floor drains. These are a gravity ball pug device, which allows water to go into the drain (at a slow restricted rate) and if the drain starts to back up, it will plug. Another more sound device to install would be a back-water valve on your sewer line outside of the house. This can be a liitle costly to say the least, but if your city sewer has backed up in the past, it is sure to back up in the future. A back water valve is highly recommended for a livable finished basement. Especially if the city's back up is what is stopping you from finishing the basement completely.

As for other moisture problems, I would recommend a dehumidifier at the very least. Basements are naturally a little moist(damp), and I think just about every basement should have a dehumidifier.

Finishing the walls with drywall, might give you a more warm homely feel, as for insulation, it is totally up to you, I think some people here gave you some nice suggestions. I personally am against insulating the ceiling. You can trap moisture in the insulation and promote rot and mold issues. ( I have seen this numerous times) Good-Luck

Thanks for the advice. We certainly should do something about the plumbing. Our main sewer pipe has a "belly" and needs love every now and then. The city backup was nasty, but the city did offer to pay for the damages. That was nice, but all we were out was a couple bottles of bleach. (Yeah, we did get the optional hepatitis immunizations for the baby.) If I put flood stoppers in the floor drains, won't it just come out somewhere higher up? I suspect I should get a pro out to figure out this stuff. The drains don't even all go to the sewer, and the manhole in the garage part of the basement? Small urban houses can be interesting, too!

Being unfinished isn't really keeping us from using the basement (flood risk actually helps us keep it cleaner, "just in case") since we use it for grubby stuff like woodworking and painting--it's actually nice to have a designated unclean area in the house. It's not big enough to be wasted space. The only finished part is the remodeled former coal bin and fortunately that doesn't flood. But I doubt it's insulated.

This is gonna be a fun project!

Consider using the owens corning rigid foam board insulation. It doesn't hold water. I think it goes to R-6. Maybe doubsle or tripple up on them and screw to to the studs.

Question about what product: I have a chalet in WV and use it two weekends a month. About the time of the first frost, millions of asian beatles (that look like ladybugs) fly in mass from the mountains and head for my chalet for warmth. When I arrive my 22' windows are black with bugs, the tub is filled, and the ceilings are alive. I cannot figure out how they are getting inside of the house. I'm thinking around the tracks of the two sliding doors maybe(?) I've asked what to use at DITY and folks say you can't fill up the sliding door track and still use the door...is there an experienced person at there with the answer?
thanks,
Peggy

A more likely entry point(s) would be the roof/attic or around the foundation/under side of the structure.