100y.o. NewEnglander - Insulation advice needed

[we'refreezing]

We're preparing to improve the insulation in this 100 year old New Englander, and need some guidance. One portion of the house is older than the other, and on the top floor has small crawl-space style storage areas up against the roof, accessible through small doors. Inside these spaces there is very old kraft-backed insulation that appears to be rockwool or similar. Much of it is falling away from the roof and exterior wall, but we were hoping to simply add more insulation over it, rather than remove it (for a number of reasons but mostly we're worried about disturbing it).

The main question is do we use faced insulation over top of it? Can we use the plastic-wrapped rolls? What is the best choice?

Thanks in advance for any advice!

[HayZee518]

that old insulation is rockwool that is extremely itchy. best to put up batt type insulation with no facing. if the insulation is on the floor, between the joists, blow cellulose insulation to a depth of 16 inches

[pushkins]

Also make sure that the insulation doesn't touch the inner side of the roof sheathing, there should be a 2" gap between insulation and sheathing. If this is a problem you can buy roof baffles at Lowe's and HD for about $1.00 a piece they sit between roof rafters/trusses and keep the insulation off and allow free flowing air.
Like mentioned previously do not cover existing "faced" insulation with any type of other "faced" insulation, buy NON faced insulation.

[we'refreezing]

Thanks!

Thanks so much for the info! I did a bit of research prior to posting, but couldn't find the clarifications you provided. Also, didn't know about the need for the 2" space - and now I'm very concerned because the insulation that is currently in place is directly up against the roof!

So, with that in mind it appears that I would need to completely remove the old insulation, install the baffles and then place new insulation. So, If that is the case, are we now better to use something other than the non-faced batts?

Really want to do this job the right way the first time, so your help is invaluable! Thanks SO MUCH!!!

[HayZee518]

big box stores and your local lumber yard has styrofoam baffles you staple into place in the rafter spaces. They're never full width so center them before you staple them. Use insulation batts non faced and fasten the batts with spring wires between the rafters. I forgot to ask, do you have a ridge vent? Also to get air flow into an attic the soffits must be open to atmosphere. that rock wool is very itchy. please wear a full body tyvek suit, a respirator, goggles and nitrile gloves. use duct tape around your wrists and ankles.

[we'refreezing]

I'm going to go up and really examine the area. I'll take some pics if necessary. Really not sure about ridge vents, also not sure about soffit vents. Obviously these are going to be important considerations, so I'm really glad I posted here! I can't thank you enough for this help! I'll check back when I have more info, so I can try to eliminate any "guessing" before I proceed.