Monster tank stand design

[Adam]

I think you're making the right choice. Fasteners flex and in construction there is a header and footer on walls. The fasteners, screws & nails, are used to hold the lumber in place not support the weight. Remember that in most cases it's not the fastener that fails it's the wood... if you get some sag in the screw/nail holes the weight will be transferred to the columns, this equals pressure points. It's not until you move up to bolts, nuts & washers do you see fasteners used in load capacity. Look at most of the elevated wood decks you see. There is a 2x10 or 2x12 bolted to the structure, with 1/2" carriage bolts, for mounting the trusses to. While the trusses are fastened in place there are truss hangers used for the real support. You wouldn't put a tank on a deck, right?

With the weight of the tank, sand, rock and water you could easily get close to 10,000lbs. With 45.8SF you have a load per SF of 218.3lbs @ 10k. Now what safety factor do you want to use? 2, 3, 4?

I hope this helps! I would hate to see all of your hard work and what looks to be beautiful aquarium end up on the floor in 5 yrs.

 

[Adam]

One last thought. Have you considered adding a pressure treated base board under the whole thing? I know you sealed the floor but you can still get condensation and any spills will accumulate at the columns and be soaked up by the untreated wood. It will only raise the stand by 1.5" and save you from rot.

 

[grouper therapy]

anit77;1050643 wrote: One last thought. Have you considered adding a pressure treated base board under the whole thing? I know you sealed the floor but you can still get condensation and any spills will accumulate at the columns and be soaked up by the untreated wood. It will only raise the stand by 1.5" and save you from rot.

The only thing with using PT here is that you have to use really dry PT otherwise it shrinks and creates flatness issues once the weight is applied. 1/8" isn't much on rough framing but can creat serious issues in regards aquariums.

 

[grouper therapy]

ghbrewer;1050637 wrote: Better than nothing, just make sure that it touches both the beam and floor squarely. Might require some sanding or careful cutting to get it to fit and touch squarely. Be careful they are not too short and/or not too long, it must be a precise fit.

Spot on a little construction adhesive doesn't hurt either.

 

[outdrsyguy1]

okay, need more suggestions. I don't want to slip PT under it as i'm concerned about messing up the level and the whole shrinkage thing. I did coat the floor really good with the garage epoxy stuff, but could I also possibly slip some plastic under the leg and fold it up? Or i could caulk around the legs to keep water from sipping underneath if I had a spill?
I've got the supports cut and test fit into place for about 11 of the 16+ supports and they are nice and snug without lifting the frame or leaving gaps, it definitely took some crazy fine tuning to do it.

I do have a couple spots where there's no good way to get underneath the frame as cross members and walls are blocking me. Can I just put a monster bolt or two through the lapped support post and the frame in those spots? Was also considering building a little bridge over the spots but if there's a bolt i'd rather go that way.

Lastly, i don't have construction adhesive. I do have that tightbond II wood glue I could use...

I will have pretty good access to the underside of the stand via the back so I could definitely monitor the legs for rot and just add new legs on either side just like i'm doing now. So maybe not a huge deal, maybe just caulk the joint at the floor after there's weight on the stand?

thanks again all!

 

[Adam]

I don't know about caulking around each leg. Sounds real tedious. Putting on its side or upside down and sealing the bottom of the legs and a few inches up would be quicker. I would seal all the wood around the sump though. That's where most of the spills will occur.
With construction adhesive you could just grab a tube extra strength liquid nails from HD or Lowe's. That should fill any small gaps. A little waxpaper under any spots you use it will keep it from sticking to the floor.

 

[outdrsyguy1]

I thought I would paint the stand with an oil based paint. However I won't be able to paint the bottom of the legs so I wasn't sure what to do to keep it from wicking up the leg from the floor. The stand probably weighs around 300 pounds now. I could probably get a jack and jack it up an inch or so and rub the bottom of the legs with oil based paint possibly.
I'm not sure what you meant above about sealing. Did you mean seal the wood with a sealer or is the oil based paint the same thing?
And use construction liquid nails for when I put the support legs into place

 

[grouper therapy]

I personally would not attempt to water proof it. I'd rather have it so that it can dry out in the event that it gets wet. Sealing and not TOTALLY water proofing can work against you. If it gets wet that often you have bigger issues. With the epoxy on the floor,I think you greatly reduced any capillary action from the concrete itself .The construction adehisive I mentioned was to use on the uprights as a gap filler if needed. Doesn't sound like you need it to me since you cut them tight.

 

[outdrsyguy1]

Gotcha on the liquid nails. There's a couple spots it would help a little where connection up top is not level due to the floor not being level.
So your saying if I had a spill and water did get into the wood you'd recommend it not being painted/sealed so it could dry out vs less chance of water getting in with it sealed but then having the sealer keep the water trapped inside.?

 

[grouper therapy]

Yep. Now if it were in contact with <u>constant</u> moisture then a complete seal would be needed such as on the outside of your house (caulk,putty ,paint, etc.) If the post were painted and it got wet where could the moisture escape?

 

[grouper therapy]

Remember water does not rot wood, fungi does. The fungi just needs the moisture to live. The different Pressure Treated woods are nothing more than an impregnation of a fungicide. Place a cheap fan under your stand and have it pull in fresh dry air from the other room once a day . Wood has to reach a moisture content of roughly 20% to start to rot. That's pretty high.

 

[grouper therapy]

I have a question though. Am I not seeing your layout correctly? Do you not have a huge fish room behind the tank? If so why the sump under the tank?

 

[outdrsyguy1]

Thanks. Here's the next issue. My center beam (2-2x6 laminated) runs over the top of a skirt 2x6 that's used as a stiffener. Since the floor is uneven the bottom skirt doesn't touch the floor a lot and I don't want to put one of the new supports on top of it. Can I support the laminated overhead beam with one 2x6 that only sits under half the laminated beam (parallel not perpendicular)?
Like this?

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[grouper therapy]

I think that would be fine considering all the other support you have there The one 2x6 supported by the post is more than enough.