I just bought a house in northern Midwest where there's lots of snow and was planning on adding blown in cellulose insulation to attic space. Then I noticed that there are no soffit vents in the main portion on the house. House has two scissor trusses in the middle and only at the lower end of each end of the house are there these soffit vents. At the one end is a garage and a knee wall so these soffits are cut off from the main house.

I'm looking for recommendations on whether I should get proper venting before insulating with 16" of cellulose. House has been updated over the years but has been in this shape for at least 10-15 years.

2 Answers 2


Is there any insulation now? If not, you might as well go whole hog and make the attic itself a part of the conditioned space. That way, you won't need soffit venting to begin with, along with its associated complications (soffit baffles, ridge venting), and it will also be more efficient if you have mechanical appliances or ductwork in the attic. Get some guys in there to spray a couple inches of closed-cell foam on the underside of your roof decking and be done with the issue entirely!


What does the roof do now?

While the ideal arrangement is certainly to sort out the soffit vents to maintain a cold roof, if the roof is not experiencing ice dams and major snow-melt as it sits, I don't think adding insulation (thus reducing heat flow to the roof) will make it worse.

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