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> this is always a difficult question.
> Are you using stationary or moving-aisle shelving?
> This should never be done on this scale without consultation with a
> structural engineer.
> The basic figuring is fairly easy to get close, but the calculation
> details should be reviewed with the structural engineer.
>
> First order approximation for fixed-aisle shelving.
> Take the linear footage weight of the records (assuming that the
> shelves will all be 12" deep and you won't make 10" deep shelves for
> the 10" records), multiply the weight per linear foot by the number
> of shelves high you plan to stack them.
> For moving aisle shelving, you're essentially done as the full load
> per square foot is what is required.
>
> You should also have a count of how many records per linear foot. For
> fixed-aisle shelving, you'll need to figure out the ratio of square
> footage of shelving to aisles and then apply that so you effectively
> spread the weight across the whole room, but beware that the
> structural engineer will also want to know point loads as for moving
> aisle shelving.
>
> 150 pounds per square foot is low for moving aisle shelving for
> videotape storage, so I suspect it's even less adequate for moving
> aisle storage for vinyl/shellac.
>
For the record (pun more-or-less intended) 10" shellac records
weigh in at about 1/2 pound each, suggesting 12" are just short
of 3/4 pound (.72 pounds to be exact).

Unsleeved 78's run about ten per inch, so ordinary paper sleeves
probably make that around 9.9 and heavier sleeves closer to 9...
which means 4.5 to 5 lbs. per foot of occupied shelving for 10"
78's, or 7 or so per foot of 12" 78's. A four-foot shelf full
of 10" 78's is holding around 225 lbs., or the equivalent of
myself (or some other slightly stout chap) sitting on it! For
12" 78's, figure around 340 lbs...so a six-foot-high set of
four-foot shelves (with six shelves 11.5" apart) for 10" 78's