[Greenbuilding] some cellulose questions

[Reuben Deumling]

My sister's attic has about 5 inches of old, possibly very old, cellulose
dust unevenly distributed between the joists.
(1) how much insulation value can one expect from what is already there?
(2) If I blow in more on top of this, how much is advised?
(3) Is there any reason to fluff up what is there before adding more? If so,
how might one go about this?
(4) What is the R-value per inch assumed to be of dense pack cellulose and
of loose fill?

Thanks.

Reuben Deumling