How much weight can 2x4’s support this 40g breeder

[eddie462]

I’m trying to find out the exact amount of weight 2x4’s can support but I cannot find out how much one can support at a given length. 
 

Here is a picture of my aquarium stand made out of 2x4s. The 4 inside vertical boards are 32” long. The other 4 vertical boards are 25.25” long. The 4 front and back horizontal boards are 36.25” long and the 4 boards on the sides are 15” long.

 

Edited February 3, 2022 by eddie462

[lefty o]

i cant give you an exact number, but that stand will likely support at least double the weight of that tank.

[MarkM]

The exact amount isn't a straight forward answer.  It varies based on many factors (grade, condition, etc).  Generally speaking a vertical 2x4 can hold a substantial amount of weight.  A single 2"x4"x8' for framing vertically can "support" like 1000lbs.

For the horizontal spans you can get a rough estimate from http://woodbin.com/calcs/sagulator/ Note, this was designed for shelves it doesn't say when it will break.  If you put 9000lbs into the calculator it will just give you how much deflection there is when clearly the wood would break long before that. To get realistic number you could google lumber span tables and dive in.

So If you want an opinion about whether a non expert thinks that tank is going to wind up on the floor because you overloaded the wood, I think you'll be fine. 

At 36" wide I'm assuming that's a 40 breeder (could be 30g, don't think its 50g or 65g) so max weight is like 450 lbs. 

Properly supported the 8 vertical 2x4 could "support" significantly more than that. 

If you were to put 450lbs load uniformly across on a 36.25" wide Eastern White Pine 1.5"x3.5" board you would get a deflection of .01inch.  You're actually spreading the load across front, back, and sides.  

 

It looks like the horizontals are supported by at least 1 vertical 2x4 directly underneath it on each end and you're not relying on screws to carry the load anywhere.  You should be sufficiently overbuilt. 

[Gideyon]

I'm not an expert, but I've watched many DIY stand videos, heard their explanations of weight, and based on them (who also aren't necessarily architects or carpenters), this stand is plenty strong.  

[Fishman Jason]

If you're asking out of general curiosity I have no idea.  But that's ok because @mpm42 rocked the factual answer.

If you're asking out of concern that tank will end up on the floor then I'd say you have nothing to worry about.  I've seen far less well built stands endure tanks of that size without fail.

[BlueLineAquaticsSC]

However big your going, make sure you floor can hold it too. My house is in a crawl space and I probably shouldn’t go above 125g

[AndEEss]

On 2/2/2022 at 7:19 PM, mpm42 said:

The exact amount isn't a straight forward answer.  It varies based on many factors (grade, condition, etc).  Generally speaking a vertical 2x4 can hold a substantial amount of weight.  A single 2"x4"x8' for framing vertically can "support" like 1000lbs.

For the horizontal spans you can get a rough estimate from http://woodbin.com/calcs/sagulator/ Note, this was designed for shelves it doesn't say when it will break.  If you put 9000lbs into the calculator it will just give you how much deflection there is when clearly the wood would break long before that. To get realistic number you could google lumber span tables and dive in.

So If you want an opinion about whether a non expert thinks that tank is going to wind up on the floor because you overloaded the wood, I think you'll be fine. 

At 36" wide I'm assuming that's a 40 breeder (could be 30g, don't think its 50g or 65g) so max weight is like 450 lbs. 

Properly supported the 8 vertical 2x4 could "support" significantly more than that. 

If you were to put 450lbs load uniformly across on a 36.25" wide Eastern White Pine 1.5"x3.5" board you would get a deflection of .01inch.  You're actually spreading the load across front, back, and sides.  

 

It looks like the horizontals are supported by at least 1 vertical 2x4 directly underneath it on each end and you're not relying on screws to carry the load anywhere.  You should be sufficiently overbuilt. 

Interesting tool. Seems to verify my own work. 
 

I recently built a stand out of hickory, with 7/8” x 6” aprons, spanning 39” between legs. Ends of the aprons are glued up using bridle joints, to 2 5/8” square legs. Everything else is 7/8” x 3”, except the feet, which are 3x3”. 
 

When I put the top on it (Ash, 25x50x1.5”), there was a tiny gap between the top and the aprons. Fraction of a millimeter. To my surprise, despite ~800lbs of water, stone and sand, the top hasn’t even sagged enough to come into contact with the apron. 

[eddie462]

On 2/2/2022 at 8:06 PM, lefty o said:

i cant give you an exact number, but that stand will likely support at least double the weight of that tank.

Thanks. I have watched videos and they all say that a 2x4 can support large amounts of weight but not how much a board can hold depending on its length.

On 2/2/2022 at 9:19 PM, mpm42 said:

The exact amount isn't a straight forward answer.  It varies based on many factors (grade, condition, etc).  Generally speaking a vertical 2x4 can hold a substantial amount of weight.  A single 2"x4"x8' for framing vertically can "support" like 1000lbs.

For the horizontal spans you can get a rough estimate from http://woodbin.com/calcs/sagulator/ Note, this was designed for shelves it doesn't say when it will break.  If you put 9000lbs into the calculator it will just give you how much deflection there is when clearly the wood would break long before that. To get realistic number you could google lumber span tables and dive in.

So If you want an opinion about whether a non expert thinks that tank is going to wind up on the floor because you overloaded the wood, I think you'll be fine. 

At 36" wide I'm assuming that's a 40 breeder (could be 30g, don't think its 50g or 65g) so max weight is like 450 lbs. 

Properly supported the 8 vertical 2x4 could "support" significantly more than that. 

If you were to put 450lbs load uniformly across on a 36.25" wide Eastern White Pine 1.5"x3.5" board you would get a deflection of .01inch.  You're actually spreading the load across front, back, and sides.  

 

It looks like the horizontals are supported by at least 1 vertical 2x4 directly underneath it on each end and you're not relying on screws to carry the load anywhere.  You should be sufficiently overbuilt. 

Thank you for your help. I updated the title as I forgot to mention the important part about this aquarium being a 40g breeder and that I used white pine wood. I live in Florida so it's probably Eastern pine.

People at my local club asked me if I knew how much weight the wood could support. I said that I didn't know and some of people snickered like a didn't know what I was doing. I don't care what these guys think of me but I should still know this information.

I wanted to be safe with the extra 25.25" boards as this was my first stand I have built and my hardwood floor isn't waterproof.

[eddie462]

On 2/2/2022 at 10:00 PM, Fishman Jason said:

If you're asking out of general curiosity I have no idea.  But that's ok because @mpm42 rocked the factual answer.

If you're asking out of concern that tank will end up on the floor then I'd say you have nothing to worry about.  I've seen far less well built stands endure tanks of that size without fail.

I'm not concerned with it collapsing, I would like an estimate on how much weight a vertical 2x4 at a given length can support. I assumed that this information would be easy to find but Google search results suck.

On 2/2/2022 at 10:09 PM, BlueLineAquaticsSC said:

However big your going, make sure you floor can hold it too. My house is in a crawl space and I probably shouldn’t go above 125g

My house is a single floor and it's on a concrete foundation so I am not concerned with that.