I can't say yea or nay about storeing negs and prints in the attic. But I can that I lost approximately 2/3 of my entire life work in photography by storing them in an insulated attic. Several years back, we had a Summer with afternoon hail nearly every day for a week or so. It was amazing to find out how much water could keak through those tiny holes, it is more amazing how much water 16x20 mounted and many framed PPofA prints can absorb during a short time. My negatives were in plastic NegaFiles inside regular steel file cabinets. The top two drawers of six cabinets files were glued into their plastic sheeths and all but a few were moved to the dumpster.
I had no clue until several months later that the roofing had failed. The thought of a leaking roof never entered my mind, but it permantly is engraved there now. I check everything now after even a small storm. The water that destroyed my photographs never reached the living quarters, so as I say we had no clue.
Again, I thank the Lord for "Bad Luck" cause with out it I woulden't have any luck at all!
Charlie......................