basment ceiling insulation

steamin

I have a house built in 1915.  I live in north eastern PA..  I want to insulate my basement due to the coldness of the upstairs floor (Living Room).  I have and old rock foundation with bilco doors.  The front erea of the house is under the porch.  Which brings in a great amount of cool air. The rest comes from the bilco door areas.  I dont want to finish my basement, but wanted to know how I could insulate the basement ceiling?  I am assuming I should try to block the air from the front porch area and the bilco doors area first.  The living room gets cold the fastest due to poor insulated basement.  Any suggestions

Brad White

Define

Take a pad of paper and define your thermal and air boundaries, (they "should" be one and the same!) for your house.



Understand that if you insulate your basement ceiling better than you are insulating your basement walls -a challenge to be sure-, you are relegating your basement to being "outside". More to the point,  the basement will be "more outside than inside". Will that subject your basement to freezing temperatures? That is the key thing to determine.



EDIT: See Mark Etherton's post below. This is what we are talking about.



Regarding the basement, strive for air sealing first, insulation last. I start with the low-hanging fruit. By this I mean, go down there on a sunny day but with the lights out. "Seal the daylights out of the place", the obvious leaks. Go after the daylight leaking in, you may be surprised.  Expanding foam is a wonderful thing. Strive for strategic application, a focused deep bead vs. "the foam dysentery" approach. A Shop Vac or compressed air gun is essential to blow out the crud first.  It is all in the details. 



Air sealing is like the zipper on your jacket. No matter how thick the jacket, leaving the zipper open (any zipper), is energy wasteful.



It also leads to social embarrassment if the zipper is just below the Equator.



For the Bilco doors, what I did at my house: Use Armaflex tape, a strip along the mating surfaces all around. Again, go for daylight.  Use this as a seating gasket. It does not always look great, but it is effective. First line of defense. Then seal the interior partition/door if there is one.



Once you have reduced the basement air leakage, then consider insulating the basement walls if you like. However, I would not think of insulating the basement ceiling before you are at this point.



I would recommend getting a blower door test done, either a single session multi-point test as a baseline, or best of all, a real-time test as you do your sealing, to measure your progress. A local energy auditor and some insulation contractors may be able to arrange this. The largest part of this is evaluating tightness limits for combustion air. Rarely will yo seal an older house tight enough to block combustion air, but you still have to know when to add it positively, with mechanical systems or ducting. If you DO seal the house tight enough to require mechanical combustion air, that is a nice problem to have. It means you have done well.



Good Luck.



Brad

Mark Eatherton

Don't forget....

Your water lines LIVE in the basement. If you do to god of a job of insulating the floor, they may end up freezing. But then, you can list the home when you sell it as having a swimming pool in the basement...



Been there, seen that and it was NOT a pretty sight.



ME

icesailor

Basement heat loss:

Before you attempt to insulate the ceiling, plug ALL the drafts. Each and every one. Cold air infiltration is far worse than loss through a wall.

I don't know where you are or how cold it gets but when I calculate heat loss in a cellar, there are two numbers used. The wall above ground and the wall below ground. The wall from grade up is exposed to the outside air temperature. As cold as it is outside, that's your heat loss basis. From grade down, it is an average but the bottom of the wall may be 50+ degrees up to 32- at grade depending on the frost. The floor is 50 to 55 degrees. If you want to get something done and the wall isn't too porous, foam insulation from the sill down to below grade will stop the drafts. If you have drafts in the cellar, you will have them upstairs. Blowing out of wall sockets and out of ceiling lights.

In Massachusetts, on new homes, you must insulate the under floor/cellar ceiling. But if you just do the edge, back 2', or just use a 4' batt, you will stop the biggest part of edge loss. Make it as thick as you can and cover the whole thickness of the rim joist. It's nice to have warmth in the cellar but insulating all the heat pipes will pay for the cost of insulation because you will not be loosing heat you can use in the heat emitting units. If you make the cellar really air tight, you won't be having frozen pipes. And I've fixed a lot of frozen pipes.