This is one concern of mine as well. The tighter I make my basement, the closer I get to having to add fresh air intakes for the furnace, water heater, and clothes dryer. I don't want to just let cold air into the open space in the basement, because that would pretty much cancel out all of my sealing efforts. I'm thinking about sealing each of the appliances, each having its own air intake from outside. I might be able to get away with letting the water heater suck air from the basement, as it has a draft hood on the vent and would be tough to seal up. The furnace has a forced draft fan, so it will need an air supply, and the dryer pumps massive amounts of air, so it will have to have its own air source as well.

My oil burner is right down on the basement floor, so I've been thinking of running some
3" diameter PVC down right next to burner's air-intake.
A check-valve would keep down the air flow, until the burner started pulling the air pressure down.
The only problem is the drier that's 15 feet away from the oil burner.. ;(

I did more sealing this weekend. I've basically started going room by room doing the DIY home leak test. I check around any trim, any outlets, windows, anywhere there is any holes or joints in the wall. Going room by room is much easier than trying to tackle the whole house at once.

One thing I found was a lot of my outlets on the outer walls were very leaky. I had installed some gaskets on some of them, but they still leak through the outlet itself. So, I went around the outside outlets/switches and sealed them up with expanding foam.

http://ecorenovator.org/forum/attach...1&d=1330912917



I even removed the outlets and sprayed foam on the inside. This seemed to be what really helped since the outside of most of the recepticals were already sealed.
http://ecorenovator.org/forum/attach...1&d=1330912917

Another area I worked on I remembered my auditor say there was a lot of leakage coming in. Its the opening to the sunroom which is an addition. So, the wall is the old exterior wall. It is also the old corner of the house which I think doesn't help much.

So, first I pulled all the trim off of the opening.

http://ecorenovator.org/forum/attach...1&d=1330913534



The top of the opening is made of two lvls spaced apart. And... looking above shows the balloon frame design that goes up and up and up. Well, at least after I pulled out that bunched up fiberglass. Anyway, I thought about how I was going to seal that up and... well I didn't come up with anything great.

http://ecorenovator.org/forum/attach...1&d=1330913548



So, I cut into the wall above it to get at things properly.

http://ecorenovator.org/forum/attach...9&d=1330913523



A little sawzall action shows the late 1800s "insulation" that was used on the house. Its another layer of lath and plaster between the inner and outer wall. Not a horrible idea in theory, but after 100+ years it begins to leak air like crazy.

http://ecorenovator.org/forum/attach...1&d=1330914200

http://ecorenovator.org/forum/attach...1&d=1330914520




So, I'm still looking for the best way to seal and now insulate this area. I'm open to ideas, but I think I'll probably just cut out as much as the lath and plaster as I can and just shove some rigid foam up there and foam around it.

I can't think of anything better. I have done small spaces like this and then put down mesh and a layer of stucco right over it. I was surprised at how strong a backer the foam makes for stucco.

Isn't putting a non fire-rated foam into an electrical box a potentially hazardous thing to do? Could be against code meaning your insurance company would fault you and not cover a house fire. I was going to make a thread about what the best way to seal my lighting fixture junction boxes where there are two knockouts punched where one is used, what you are doing is pretty much the same idea. I was thinking along the lines of liquid electrical tape would be the safest. I noticed my foam switch/outlet gasket material has UL marks on it. I would hate to see a house burn down from some arcing in the electrical box that might otherwise trip a breaker and normally be isolated in the box become a fire. Have you put any thought into that?

I did not use fire rated expanding foam, but it is made. For the tiny bit of foam that is in there, I'm not worried about it. A good thing to mention though, especially with an older home that may have old wiring.

GREAT STUFF? Fireblock Electrical Sealant | Home Fire Protection

http://greatstuff.dow.com/image/fireblock_rt.png

That stuff looks good. I just looked at my fire rated caulk and on its 'great for use around' wires is included. I suppose this would be the best to use as it won't take internal room up inside of electric boxes in case things get sloppy with foam, as the air volume is supposed to be enough to prevent from overheat.

I finished up with this section. I had some polyiso left over from doing the attic. I just needed a few strips here and there. I cut them to fit and then just filled around the edges with the expanding foam to keep it in place.

Started with a few pieces. I made sure to get two layers of 1" polyiso against the outer wall.

http://ecorenovator.org/forum/attach...1&d=1331083121

http://ecorenovator.org/forum/attach...1&d=1331083158

http://ecorenovator.org/forum/attach...1&d=1331083158