I'm minding a bunch of LPs (about six big boxes) for someone who's away for a few years, and have had to clear them out of the attic while it's being insulated.

When I put them back in, I'd prefer to have them in plastic boxes for neatness. Or bookshelves - but my attic is not really intended for heavy weight; the joists are designed for holding up a roof, not for the extra weight of furniture.

The local tidy-up shop has offered to sell me large covered plastic boxes which fit LPs exactly. Is this a good choice? Should I get those anti-damp granules (where?) and drop a couple of packets in each box?