I currently have 6 - 8 inches of cellulose blown in insulation in my attic. I live in Michigan and energystar.gov is recommending a total of R49 - 60. From what I can tell only have about R19-25 based on the chart in the link below. I need to increase my R-value as cheaply as possible. I live in an old farmhouse (circa 1910) and have plaster ceilings and am concerned that if I get up there to add some fiberglass batt insulation I may crack some plaster simply by walking on the joists or accidentally put my foot through since I cannot see through the cellulose to the joists. Any suggestions?
We just usually bring up a couple of 2x8s at about 10' a piece and use as walkways. You can't really do much with blown in insulation other than add more to it. Cost of 2x8s (you can get the "bad" ones from big box for $5) and insulation + renting a machine (most are free given you buy X amount of insulation) is about a $400-600 job for most mid sized houses.