# critique this stand, will it gold 3000 pounds?



## marvelouzone

SO I'm building a stand for a custom aquarium which measure 96"L, 24"H, 30"D. it's 300 gallons which is around 2400lbs, plus 200lbs aquarium weight, will probably have about 300lbs of sand, and misc. stuff.. SO the Drawing is using lumber I already have.. Someone wlse recommended I use 2×6 Stringers on top front and back, but I'm trying to leave as much space inside stand as it will be where filters and sump is, which will be about 48Lx23h,12D.. I'd like to be able to remove sump if necessary to maintenance it.. Here's a picture of my idea.. It will be wrapped in 1/4" oak, stained and poly'ed, plan on building doors for stand as well.. the 4 corner post are 4×4 with notches cut for 2×4's to rest on, other 4 post in center are 2×4..


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## Kazooman

Geez, that is a lot of weight, and you really do not want the center section to sag. I think sagging in the middle is a real issue here. I would suggest beefing up the verticals in the central upright supports to carry the weight. If it were me, I would also make the entire upper frame out of four by fours. That may well all be over kill for the job at hand, and a real engineer can probably tell us so, using parameters set for great lumber. Most lumber we get these days is not so great. My guess is that your investment in the aquarium, peripherals, fish, etc. is an order of magnitude greater than the cost of beefy lumber to make a really sturdy base. I would go heavier, rather than try for the minimal acceptable size, but that is just my opinion. Do you want to remove the fish, drain the tank, scoop out the sand and whatever, then remove the tank to later add some heft to the frame?


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## bobasaurus

I wouldn't count on it, looks subject to racking and sagging. You might want to look up existing plans for aquarium stands.


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## AZWoody

I used to be into aquariums before. Was my main hobby and you can google DIY aquarium stands and you will see lots of examples.

What you have is pretty standard except a lot of people would double up on the 2×4s on the top frame but the 4×4s in the corners will hold the weight.
Some also would put the 4×4s in the 2 center supports as well and probably wouldn't be a bad idea to do for this either.

If i was making one from scratch, I probably would have more than 2 columns in the middle but I do understand you need to have room for a sump and filters as well.


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## natenaaron

This is just my opinion. I don't see nearly enough support there. I am with Kazooman Over build that puppy.

The weight you want to support is not something I would trust to lumber unless I knew exactly what I was doing. I would go steel and face with wood. Do it right and no one will see the steel. Go industrial and mix the steel and wood. You don't want that much weight coming down on someone..

Have you checked to see if where you are putting it can stand that much weight in such a small area? The stand will be very heavy if you do it right no matter what you build it out of.


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## Stewbot

I have built a couple of these, the biggest being for a 100-120 gallon tank, I can't remember but significantly smaller than yours. I had less need for space underneath and was most concerned about its strength, being that it was going to sit in somebody else's living room. I basically needed to be sure and didn't want to try and get tricky with the design. Although a much more clunky approach, I framed it as I would walls for a house, except with 2×3. For the access into the cabinet, I simply did a jack and king stud with a 4×4 header. The material used horizontally across the studs prevented racking. Based on yours plans and a need for space underneath I can see that you are looking for a more clever approach, but just thought I would share.


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## Luthierman

A 2×4 can only hold around 370 lbs per 6 feet. You need bigger lumber and more of it.


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## marvelouzone

> A 2×4 can only hold around 370 lbs per 6 feet. You need bigger lumber and more of it.
> 
> - Luthierman


that is true, but there is no 6ft span unsupported, the longest length unsupported is 28.5 and its on edge, that 370 is when perpendicular to grain right? was hoping someone would have calculations.. might have to dig some up


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## Luthierman

The 370 is on edge too. Or you could say the 3.5 going vertical. I understand that you have quite a bit less than 6 ft unsupported, I just know that weight ratings are not meant to be exceeded or even met. I would make sure your structure can hold 6000 lbs, not just the minimum.

Check out this site. http://www.woodbin.com/calcs/sagulator/


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## marvelouzone

> The 370 is on edge too. Or you could say the 3.5 going vertical. I understand that you have quite a bit less than 6 ft unsupported, I just know that weight ratings are not meant to be exceeded or even met. I would make sure your structure can hold 6000 lbs, not just the minimum.
> 
> Check out this site. http://www.woodbin.com/calcs/sagulator/
> 
> - Luthierman


that is the plan I'm going for a safety factor of 2.5 to 3.. I will do some more calculating, I'm getting conflicting information from some engineers on another forum…


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## marvelouzone

> The 370 is on edge too. Or you could say the 3.5 going vertical. I understand that you have quite a bit less than 6 ft unsupported, I just know that weight ratings are not meant to be exceeded or even met. I would make sure your structure can hold 6000 lbs, not just the minimum.
> 
> Check out this site. http://www.woodbin.com/calcs/sagulator/
> 
> - Luthierman


if you plug those same numbers in you just gave me 
72" span at 1.5 front to back 3.5 depth it says that a single 2×4 can handle total 800lbs with only .02 sag which is acceptable by there calculator.. if you plug in 29 in as length(longest length unsupported 28.5") it says it would take 5000lbs with .02 sag… in theory 8 sections that could take 5000lbs… now a single 4×4 post is supposed to be able to take 7800 lbs.. we have 4 of those and 4 2×4 post, the 4×4 post are notched so they contact the ground as well. It seems I am already at a safety factor of 3.. I'm also considering that the weight is evenly distributed throughout the whole stand and not just one point..


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## Luthierman

Yes, but remember that would be clear lumber with straight grain. I don't know how to factor in knots. I'm not saying no to your design. I am saying I really like to make sure it can do what it is supposed to do. Don't forget to bolster you floors while you are at it. It would really suck to have a floor joist give out due to the weight.


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## bigblockyeti

One thing to consider is the bottom of the aquarium, what is it made from and how thick? What will be the support requirements to keep it from falling out of the bottom of the tank? It could be 1/8" non-tempered plate glass or 1 1/2" Lexan needing only a perimeter support. As for the unsupported span, the front and rear panes of the tank will be in vertical shear both offering substantial beam strength. The vertical members of the tank stand alone would be able to support the weight absent of the horizontal members (in theory if you could get them to not fall over). As for racking, it might be a better idea to use a heavier (1/2") construction grade plywood glued and screwed to the back and sides before wrapping in 1/4" oak.


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## timbertailor

I think a torsion box is a far better design to start with.

Glass does not flex. Any sagging will cause a failure.


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## sras

One thing to keep in mind is lateral forces - think of someone losing their balance running into an end. You'l want to consider a way to make your joints strong enough.

Also - being only 12" deep you'll want to consider anchoring the stand to the wall.


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## helluvawreck

Are you building this for yourself or someone else?

helluvawreck aka Charles
http://woodworkingexpo.wordpress.com


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## MrRon

The structure as shown will be sufficient to hold the weight. You need 3/4 plywood for the back to prevent racking. Provide a door in the end of the stand for removal of the sump, as you will not be able to remove it through the front. I have a similar set-up and the problem was install/removal of the sump. On mine, I wrapped all four sides with 3/4 plywood and cut openings for the doors.
One other thing to be concerned about is your floor. If you are in a house with a basement or crawl space, you need to reinforce the joists under the floor. Position the aquarium stand as close to a floor joist. If the span is too long, you need to sister the joist with another 2x. or add a column support. Headers may also be needed. Slab on grade; you will be OK. Mobile home; forget it.


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## Ghidrah

The 4X4s will take the vertical load, but the span between the mid partitions is too long, I'd go 3 partitions and shoulder them to the rails which I would also go with doublers or 4X4. I'd also add intermediate joists between the partitions top and bottom to redistribute the load.

Will the sides be shelving and access ports to the underside of the tank? For lateral strength you're going to need reinforcement all the way around whether it's diagonal reinforcement or a combination of diagonal and sheathing, (ply).

For perspective sake, you estimate 3000 lbs, 96X30= 20sqft of surface. 3000/20= 150lbs per sqft.

1. What will the top of the cabinet consist of and will it support the weight of all items without sag?
2. Will this cabinet and tank be on a concrete slab or a wooden floor?
3. The average residential wood floor dead/live load design is between 35 and 50 lbs per sqft relative to 2X8 or 2X10 joists @16"Ø, covered by 3/4" T&G subfloor glued and nailed in place to the joists and with solid wood or metal bridging between the joists.
4. The closer the object is to a bearing support, (girt or foundation) the less the joist deflection will be if the object is crossing as many joists as possible.
5. This does not eliminate possible future failure. I'd invest the money in an engineer before I went any further than cabinet design to ensure the floor and load bearing supports will support the dead load over an extended period. I would implement any and all proposals made by the engineer and have my designs reviewed by the town hall building department for a permit if needed. This will cover you regarding your insurance co. if any mischance occurs in the future

IMO


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## AZWoody

Most aquariums have all their weight resting on the perimeter.

This is a normal design for aquarium stands. There is generally no table top or anything like that.
The only thing that has to be determined is the weight capacity on the outside edges.

No need to reinvent the wheel. There are plenty of plans and photos on the internet of aquarium stands. 
His design is normal, it just has to be determined whether some things need to be beefed up a bit.


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## marvelouzone

you guys are great and a weath of knowledge


> One thing to consider is the bottom of the aquarium, what is it made from and how thick? What will be the support requirements to keep it from falling out of the bottom of the tank? It could be 1/8" non-tempered plate glass or 1 1/2" Lexan needing only a perimeter support. As for the unsupported span, the front and rear panes of the tank will be in vertical shear both offering substantial beam strength. The vertical members of the tank stand alone would be able to support the weight absent of the horizontal members (in theory if you could get them to not fall over). As for racking, it might be a better idea to use a heavier (1/2") construction grade plywood glued and screwed to the back and sides before wrapping in 1/4" oak.
> 
> - bigblockyeti


 It's actually a custom aquarium made from 3/4" oak with 2 acrylic viewing windows, the inside is coated with fiberglass, and pond armor epoxy, will post a pic to give you better idea.. the outside is stained and poly'ed


> One thing to keep in mind is lateral forces - think of someone losing their balance running into an end. You l want to consider a way to make your joints strong enough.
> 
> Also - being only 12" deep you ll want to consider anchoring the stand to the wall.
> 
> - sras


not sure what you mean by 12" Deep, it's 30" front to back



> Are you building this for yourself or someone else?
> 
> helluvawreck aka Charles
> http://woodworkingexpo.wordpress.com
> 
> - helluvawreck


this is for me



> The structure as shown will be sufficient to hold the weight. You need 3/4 plywood for the back to prevent racking. Provide a door in the end of the stand for removal of the sump, as you will not be able to remove it through the front. I have a similar set-up and the problem was install/removal of the sump. On mine, I wrapped all four sides with 3/4 plywood and cut openings for the doors.
> One other thing to be concerned about is your floor. If you are in a house with a basement or crawl space, you need to reinforce the joists under the floor. Position the aquarium stand as close to a floor joist. If the span is too long, you need to sister the joist with another 2x. or add a column support. Headers may also be needed. Slab on grade; you will be OK. Mobile home; forget it.
> 
> - MrRon


It's on a first floor, perpendicular to floor joist 2×10 16 o.c. Its up against and exterior wall, the 2×10 rest on a 12" thick double cinderblock wall, I have also put up 3 4×4 post with one 4×4 post crossing the bottom of 2×10's 30" out where the front of the stand will rest. the basement floor is concrete.. it will cross 6 joist..


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## oldnovice

Check with JoeyG as he has built a very large stand in this post.


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