Insulation, Radiant and Vapor Barriers - Need help with attic insulation question!

I have an insulation question. My home is balloon frame with a second floor where the rooms have 4-foot knee walls and slanted ceilings. I had blown in insulation put in the exterior walls last spring and it made a noticeable difference on the first floor. However, the second floor was not as noticeable and the reason is that the slanted ceilings have no insulation behind them between the rafters…. Just drywall, dead space between the rafters and the roof sheeting.

I want to have blown insulation shot from the attic down into those wall cavities. However, I do not have vented soffits and eaves. Being an older home, my eaves have exposed, scrolled rafter tails and the underside between them is beaded tongue and groove. I know in today’s world, the eaves would be vented, you install baffles in the rafters and insulation over that.

I do have gable vents on each end of the attic.

It would seem that I should just have the blown in done but is there anything I should be concerned about? Ice dams or loss of life of the roof, which hardly seems possible given that the there is no ventilation there no allowing the roof to be somewhat cooled during the summer. I live in upstate NY and wasting money heating my house given today’s energy costs seems ridiculous.

Thanks.

So if I understand correctly:

1. There is a vent at each end of your house
2. There are no soffit vents at the roof line

If thats the case, you should be fine with filling up those bays with cellulose with no problem. The ventilation issues is still theory. Some people believe you don't need it in all situations and others say you will die if you don't have it everywhere(well, not literally). I've heard that some shingle manufacturers are removing that from their warranty, meaning that you won't get nailed if you don't have ventilation(don't quote me though because I haven't actually looked into it yet!). We've done a couple of houses where there were vents at the peak of the roof but no soffits so we just filled up the whole bay. Air won't circulate unless there is a vent at the top and bottom of the roof(unless it goes into a open attic with other vents). Anyway, you should be fine. And if something were to happen, you could always vacuum out the attic bays and leave the walls full. Good luck! Make sure they pressure pack the walls if they can. Might be difficult.

Thanks for the reply. Yes, I have gable vents on each end. But as you stated, there is no air movement currently where I need insualtion due to no vents at the eaves/soffits.

I'm going to get this done before the winter, hopefully it helps.

Are you sure that all the kneewalls have proper insulation? If you cant get access to them from an access door it might be worthwhile to cut into it. If the kneewalls are to small for you to fit into then drill 3 inch holes between the stud spaces all along the kneewalls close to the top and just fill the entire space with cellulose. The slanted ceilings are another problem. If you cant get behind the kneewall then in addition to what i wrote above you should do it from the attic. Cut sections of R13 batts and stuiff them into plastic bags and with a long stick or 1X4 push it down all the way to the bottom of the slanted ceiling. Make it thick enough so that it wont drop down behind the kneewall though and then fill up the slant with cellulose. That 4 ft kneewall is the biggest problem though and if its small enough you can usually get by with just filling it up. I did the same in my cape cod house with bonus room over the garage. I filled a 5.5 ft X20 X2 ft kneewall space with cellulose and solved that rooms problems.