I have a cape style house with no access to my attic. This summer I plan on getting in there through the roof/cutting a hole. While up there I would like to do 2 things. add insulation and install a whole house fan. My question is this. If I install the whole house fan and then blow in cellulose insulation when I turn on the fan what happens to the insulation? Will it get blown out through the vents? Do I need to put plywood or something over it? I also have very little space between my rafters and roof, will this be a problem? Lastly, how do I calculate my attic ventilation I have 2 small gable vents and a ridge vent. Thanks