Hey, I am putting my new tank into the room (currently in garage) shortly. And figured now would be a good time to quickly ask here to confirm (I've done some figuring and think I should be good in general). Anyway...
Here is build thread with particulars on tank and stand:
https://www.reef2reef.com/threads/first-build-some-questions-and-documenting-my-build.241255/
The tank is 48" long 65gal, with 20gal long sump. Stand is 55" long wood stand, very over-built. should distribute weight nicely along the floor.
Things contributing to weight:
Display is 65gal 10mm glass, I'd guess it weighs 80lb, will have 50lb dry rock, and about 5-10lb live rock. And I have purchased 80lb of sand, but not sure how much I'll need to use.
Sump is 20gal long, probably weighs about 25lb to 30lb will only be filled to 9" deep, which is about 15gal, will have a little sand in the fuge chamber (prob 10-15 lb) and some rubble (maybe 5-10lb).
Pump/skimmer/plumbing probably total another 25lb give or take.
I'd account for a couple more gallon of water in the plumbing when operating
Stand weighs about 150lb, maybe a little more.
The Room:
First off, this is a house, not an apartment building. I'm placing the tank on the ground floor (with basement underneath it).
The room is my dining room. It's got very minimal furniture (small dining table, and 4 chairs, all of which are light).
Room has usually only my wife and I. I'm a big guy so lets say 500lb worth of people usual load. That may go up to at most 1000lb of people if we have guests and such.
The room is about 14' long by 10' wide. There is a steel I beam running across the room at about 4' from one wall, leaving a 10' square floor space with joists carrying the weight. (the other 4' x 10' section is seperate joists). The I beam is supported with steel Jack posts on one end of the dining room and concrete foundation on the other end.
The "back wall" (opposite the open end of the room where the I beam runs) is a solid, reinforced, poured concrete foundation wall.
The basement under the room is our laundry room, and is unfinished, so I can see the joists/structure clearly.
The joists run from that foundation wall, to the I beam.
Joists are 2x10, on 16" centers, running 10 feet. They are cross braced with X bracing twice across that length.
There are a couple small drills for electrical, but those are closer to the I beam end.
The tank will be going against the short wall right up against the concrete foundation wall. with the 55" stand running perpendicular to the joist direction.
My assumptions/conclusions:
So based on building code (40lb/sq foot) the 10' square segment of the room should handle 4000lb of live load evenly distributed.
The section of joists where the stand load is focused is 55" x 10' which is about 45 square feet. Should handle 1800lb evenly distributed.
Total weight of the entire system supported by the stand (including the stand itself) should be approx 1200lb
Weight will be focused right against a solid concrete reinforced foundation wall, and load is only 20" out from the wall at most (stand is 20" front to back). Meaning that the vast majority of the weight is being carried by the foundation wall, with the main concern being shearing failure of the 2x10 joists.
In addition, based on observed structure, the flooring in that room should be able to take a safe live load much higher than the building code. (AWC tables show that with 16" centers standard grade 2 or better 2x10 joists on a 10' span, will support a 100lb/sq foot live load with safety margin in standard home building conditions, with shearing strength of 150lb/sq inch for the bearing ends. If we assume at least 3" - 4" over that concrete wall, and the same over the I beam, shearing strength per-joist should be approx 900lb per joist. So if I can span 3 joists that's 2700lb shearing strength, and 4 joists that's 3600lb.
Anyway long story short, I think I'm perfectly fine, assuming there are no major defects/issues in that wood (such as rot/pests, and so on). Which it appears good in that regard based on visual inspection.
So even if I manage to get 1000lb of people crowded closely around the tank, that's a focused load of say 2500lb on the peak on that section of floor, which should still be well within the safe loading limits of the observed structure.
All that said, I'm no structural engineer, so I'd love to hear a more informed opinion on the above
Thanks!