Any insulation questions??

[james]

My guess is that there is a lot of air leakage going on underneath the cellulose. Ideally, the attic floor would have been completely airsealed before cellulose was added, but this does not always happen. I would start by looking for plumbing stacks, electrical penetrations, etc and foaming them. Look for dropped soffits and changes in height of ceiling. There could be bigh leaks associated with this area. Do not foam anything that produces heat like a recessed light or chimney. Work smart and safe. You are responsible for your house's safety, if you do it yourself. Do a little homework before you start on the internet to see how other people have done it. Check the top plates and see how big of a gap there is. This will be difficult because the cellulose is difficult to clean out, but anything you can seal will yield lower energy bills and make the insulation you have more effective. Make sure there is adequate ventilation in your attic. Airsealing will reduce the amount of water vapor entering the attic from the house, but will also make your house tighter. This means that bath and kitchen fans become more important. Make sure both vent securely to the outside.

You could check how much insulation you have up there. In central NY we add cellulose to a total depth of 15.5 inches. so if you have less than that, you could add more after you air seal.
good luck,
-James

[DamageX]

Yeah, there is nowhere near 15 inches of it, maybe 5" at best. It's an old building and hasn't been kept up that well. All of the ceilings and most of the walls are sheetrock with the edges being plastered so I can't see there being much air leakage, aside from a plumbing vent pipe which could use some sealing. Anything else to look out for?

[james]

There is probably a lot of other spots where air leakage is occurring. Draw a map of the house on the 2nd floor including all walls and light fixtures. then go up in the attic with your map and clean the insulation away from the light fixtures and foam them. Use your map to find the top plates (top of the walls below). clean the insulation off and you will find penetrations where wires go down into the wall. Seal those with spray foam. Do not foam anything that gets hot like a recessed light. Look for chimneys and seal around them with a fire proof material like fiberglass duct board and duct mastic. When you are done with all of this it then makes sense to bring the insulation up to 15 inches or so. If you don't airseal first it is a waste of money.
-James