Can 8x8x8 stone blocks (grey and hollow,) hold up a full 55 gallon fish tank?
I want to make a two foot high shelf for my aquarium. The tank is 48"x20"x14" (length,height,depth). Blocks with be stacks of 3 high, 3 stacks across, covered by redwood planks. The stone blocks are the kind used in construction. It will be in my patio, under a partly covered overhang. Will the blocks crumble over time under the weight of the tank, which i heard will be 600 lbs when full? Will it hold up in a small earthquake? Will the redwood planks give way over time due to being outdoors and subject to a little splash or drip of water occassionally?
6 Responses
s m
03 Apr 2011
kajunattitude
03 Apr 2011
I’d check the weight capacity. maybe thru a hardware store or online somewhere
randy s
03 Apr 2011
sure as long as hollow end is up
mjboog2
03 Apr 2011
It should be fine. Cinder blocks have high compressive strength. People have used them for footers on decks, and that’s what is used to set up a mobile home (which I promise is way more than 600 pounds. They are set up in single stacks however high they need to be for leveling. They shouldn’t crumble. The redwood shouldn’t give way as long as it has enough support underneath (which it sounds like you do).
fiddlesticks9
03 Apr 2011
No problem with the blocks especially if the blocks are sitting on a level, solid surface and the hollows are pointing UP.
Redwood is rot-resistant wood, it shouldn’t be a problem either.
Kurtis G
03 Apr 2011
The blocks are designed and used to support buildings. If they couldn’t support a fish tank there’d be a lot of rubble heaps lining our streets!
Concrete Masonry Units (CMU blocks) are used not just as footings in porches, mobile homes, and patios, they are used as full height foundation walls at only 1 block wide and more than 10 high. So yes your tank will be supported easily by the block with the hole side up. As for standing up to an eathquake… I don’t know much about shear forces impacting structures as I don’t live in an area with earthquakes, but CMUs are the best option I would think. The redwood should be fine as well. I would be more concerned with what is under the tank and CMUs…. if the patio is framed with floor joists (like a deck), this wont work unless you put some other support under it as the joists will sag. If it is just patio pavers stones or something like that those will probably crack and I would remove enough of an area to put the tank and supports and bear directly on the earth. (Or if you can, dig into the ground and put a course or two below grade). The compressive strength of the tank should make sure the whole thing doenst tip over, but I would grout the blocks solid (fill in the holes when stacking) if I were you. Good luck!