I need the input from some of you insulation gurus to know how to proceed with this house. Originally a ranch, it is now conisdered a cape, since part of the attic was bumped out to form two extra bedrooms and a bath. A door in the hallway leads to the unfinished part of the attic. There is ample room to stand up in most of it, and there is a crawl space over the bedroom wing. There are two air handlers (system is hydronic forced air), one in the standup part, and one in the crawl space. The old insulation, rock wool, is mostly exposed and dirty at this point, and dried out and flaking. I know we get some of the filaments coming down through high hat openings in the bathrooms, and I'm convinced, althoughthe HVAc company says "no", that a good bit of it is getting into the duct work, which explains a very dusty house, and problems breathing since we moved here three years ago. W had major ice dam issues for two years, owing to the heat in the attic,and a warm roof. We just had a second roofing job done (yes, we have done two), now bringing the ice shield down over the eaves onto the soffits, to prevent water backup from the gutters as the ice melted. This has also, I think, warmed up the attic even more. The HVAC company does not want to see the temps dropped up there, due to the equipment. I had two insulation guys here, one of whom wants to rip out everything accessible, including the insulation in the crawl space, which is stuffed between the beams . There is no actual floor in that section. I worry about the electrical and plumbing lines, and damage which might be done while they rip out and replace. They also want to insulate the ceiling, effectively making the attic part of the living space - which would aso, they say, keep the warm air from going up to the roof, and protect the equipment. Second insulation guy says it is imppossible to rip out the old insulation on the floor of the crawl space ( perhaps it is just too much work??) and wants to staple new insulation over it, but remove and replace what is accessible in the main part of the attic. He has said "no" to insulating the roof line, stating that in the summer it would be hotter than Hell!! Someone else told me it could cause the roof to rot (vapor barrier?). So now I have two different takes on this, but my major concern is getting rid of the loose stuff which is permeating the house, as much as possible, and possibly keeping the air a little cleaner. Another aspect of this might be keeping the warm air on the first floor from going up to the second floor, costing a lot more to heat the house. I just don't know which of these guys makes more sense, and whether one or the other has a valid argument. Can anyone help with this??? Thanks!

First I'm assuming that you're talking about fiberglass batt insulation. If it is just matted down because it has been stepped on, then yes you can can fluff it back up to a larger thickness. If it has been rearranged to form nests, then your best bet is probably to remove and replace it with new. Depending on the extent of the activity, the possibility exists that it is covered with urine, droppings, etc. from the rodents and (assuming that all activitiy has been arrested) you may want to clean out the attic and re-insulate anyway. I know first-hand that this is a real crappy job, but worth it when it's done. Check any wiring up there also to see if they gnawed on it.

These situations usually still bleed a lot of hot air into the attic, even with weatherstripping. Something I did was to build a 'storm door.' In the attic,I build a frame up about 5" and placed a piece of wood on that, hinged to the frame. After weatherstripping and insulating that part as well, my heat losses at the door were no greater than the rest of the ceiling.

Thanks Ionized, Energy_Rater and Mike_Home, As there is no compelling reason to remove existing insulation, it seems best to leave what's there in place. But the kraft paper has to be removed. These are R-values for the two products: Fiberglass, 2.2 to 2.7 per inch; Rockwool, 3.0 to 3.3 per inch. Using the median number of both, I estimate the current installation's R-value at 16. CURRENT INSULATION'S R-VALUE Fiberglass: 2.5R x 4" = 10 R Rockwool: 3.1R x 2" = 6.2 R To get up to 30R, another 14R is needed which is: 5.6" of Fiberglass or 4.5" of Rockwool. So, laying one batt will get close to 30 R which is adequate as Mike suggested. Is it OK to lay Rockwool on top of the current fiberglass (after the paper is stripped off)? Below is a link on how to dress for installing insulation. Fiberglass asks for more dress-up than does Rockwool...a different sort of date. ;-) This same website provided the R-values in the article on "How to compare f/g and r/w". Gosh, you've all been so helpful. I am very grateful. Thank you. Here is a link that might be useful: How to Dress for Working With Fiberglass Insulation