Cinder Block Stand Questions + Reinforcing Cabinet?

I'm looking to make a cheap aquarium stand for my 20 gallon long. I'm thinking cinder blocks would be the most ideal thing to use in this case. My plan is to use two 2x8's on top and four 8x8x16 cinder blocks. Two on each end of the stand.

My question is...and I don't know if it even matters, which layout would be the most sturdy or safe? If I did #3, there would only be a 14" space in the middle under the tank.

 

I would go for the #2 model. I give a couple inches of forgiveness because I always bump into things.

#3 is fine too, are you concerned because you want room for a sump?

Model #1 would concern me with the middle bowing over time. Though I am semI guilty of this... I have a 20L on a 40B stand

 

I would go for the #2 model. I give a couple inches of forgiveness because I always bump into things.

#3 is fine too, are you concerned because you want room for a sump?

Model #1 would concern me with the middle bowing over time. Though I am semI guilty of this... I have a 20L on a 40B stand

I won't be using a sump, I was thinking about the wood bowing over time and ideally i'd like this to last a while. A little bit of storage room underneath wouldn't be a bad thing either.

If I can't find the cinder blocks that are perfectly rectangle, do these work just the same?

 

I won't be using a sump, I was thinking about the wood bowing over time and ideally i'd like this to last a while. A little bit of storage room underneath wouldn't be a bad thing either.

If I can't find the cinder blocks that are perfectly rectangle, do these work just the same?
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I would think so, but I have no experience using them so I can’t say...
I can only give one tip here and that’s if you run into problems with the 2x8’s being flat you can cut a peice of plywood to put on top. Will take any imperfections out of the 2x8’s. I only mention this because cider blocks aren’t all the same so you may have some unbalancing to mess with.

Good luck!

 

How many 2x8s are you using? 1, 2? Honestly, I doubt if you would ever have an issue but if you are concerned, use model 2 or 3. I would personally use model 1 with about 2 inches of tank on each end over the cinder blocks.
When you use the cinder blocks make sure to have the holes face up, as that is how they are the strongest.

The thing that I would make sure of is that you make the stand as flat and level for the tank as possible. Otherwise, the tank may give way...
Although that may only apply to large tanks, I'm not sure.

 

How many 2x8s are you using? 1, 2? Honestly, I doubt if you would ever have an issue but if you are concerned, use model 2 or 3. I would personally use model 1 with about 2 inches of tank on each end over the cinder blocks.
When you use the cinder blocks make sure to have the holes face up, as that is how they are the strongest.

The thing that I would make sure of is that you make the stand as flat and lever for the tank as possible. Otherwise, the tank may give way...
Although that may only apply to large tanks, I'm not sure.

I'm going to use two 2x8s. I'll definitely make sure everything is level before the tank is filled.

 

All 3 would work with 2x8's. A 20l is only about 200lbs filled.

 

Would I need to seal the wood or can I just use a table protector? Kind of the spongey stuff with octagon shapes.

 

I used 3/4" plywood on a wire shelf for some 20 gallon longs and didn't seal it but I did sand them. In hindsight, I should've sealed or painted the wood.

 

The whole reason i'm looking to do this cinder block stand is because I got water on my particle board cabinet a few times and got the laminate layer wet. It made me kind of nervous, but it dried up. Someone suggested to put plywood over the top of it. Would this work for structural integrity? Would it be safe long term? The cabinet is super sturdy, heavy and I can't move it easily. It would definitely save me the hassle of getting heavy cinder blocks lol

 

Particle board is completely different than solid wood boards. Particle board under the laminate usually swells and falls apart when it gets wet. I had a particle board stand for a 55 gallon years ago with LOTS of water damage that never failed though but I wouldn't do that again. Ever.

That said, a 20 gallon long shouldn't have a problem on that stand since it's a fairly light tank. Just be careful with spillage.

 

Particle board is completely different than solid wood boards. Particle board under the laminate usually swells and falls apart when it gets wet. I had a particle board stand for a 55 gallon years ago with LOTS of water damage that never failed though but I wouldn't do that again. Ever.

That said, a 20 gallon long shouldn't have a problem on that stand since it's a fairly light tank. Just be careful with spillage.

See, that makes me nervous. I'm not really sure what to do. It seems like every water change i'm spilling water on it one way or another.

 

It should be fine...here's King of DIY video of him using cinder blocks. This is an old video, today he's obviously on some kind of protein kick.

 

Just be careful with spillage.

I guess you wouldn't have any ideas as to how to waterproof it? It's such a sturdy stand; but the "veneer" layer on top seems to be able to get wet at the sides of the wood easily since that's where it meets.

 

Paint it with latex paint?

 

I guess you wouldn't have any ideas as to how to waterproof it? It's such a sturdy stand; but the "veneer" layer on top seems to be able to get wet at the sides of the wood easily since that's where it meets.

Latex paint is a good option for the existing cabinet, but maybe you don't want that. My marineland stand is particle board and gets a few drips ever WC but seems fine. I understand your concern and share it, however, all my tank stands have been particle board and I've never had an issue.
I would paint the 2x8s and or the plywood cabinet cover with exterior grade gloss (lightly sand between coats for the super shiny gloss)
Also, I built a kitchen cabinet recently that had primer, exterior paint, and urethane to protect against utensils and scuffs. REALLY water proof
Adding a plywood topper to your existing cabinet can protect it from spills BUT, also may let water under it, which could cause bigger problems later.

 

The easiest way to prevent water damage is to put a thick piece if plastic on the top of the cabinet.

 

Just reinforce the inside of the cabinet with 2x4s.
You can always make one out of wood and put wheels on it.

 

Bumping up an old thread of mine...

Back in May I took the 15 gallon off of the cabinet and upgraded the tank (with a different table). At the end of it, the cabinet was bowing every so slightly in the middle and opening the doors on the front of it wasn't as easy as before. It's no longer bowed though... could of been because the tank was a smaller footprint so more weight was in the middle.

Regardless, would that deem the cabinet unsuitable for a 20 high or 29 gallon with a 1/2" plywood cover? The old tank was 16" long, 20h is 24" long, 29 gallon is 30" long and the cabinet is about 32" give or take, so it would cover most of the top.

 

Have posted before about making a tank rack from 2X4s. Was intending to hold 3 20 or 29 gal tanks, but now I’m thinking bigger. . . Now I still plan on making the smaller rack for breeding but will need something for grow out (also want to keep some big fish for the enjoyment). Was thinking 2 tanks per rack anywhere from 55-125 gal. . . Saw some videos (specifically the aquarium coop one) on cinderblock racks. Would blocks and 2x4/4x4 work for such big tanks? Is stacking the cinderblocks that high safe without somehow securing them? Maybe a big tank on the bottom (with center supports under) and a 55 above?

Mind you this is all pretty far off but. . . Knowledge is power right?

 

I can't vouch for a big tank on cinders but my 29-20 and 10 are all on cinders. and if I were to set up a large tank I would definitely go the cinderblock route again without a doubt. For my 29 and 20 I used 8 blocks and 2 pieces of 1/2" plywood for each tank. I put a single cinder then ran the plywood across then placed the other 3 on each side and added the plywood. For my 10 all I did was a single pile of 4 cinders with a piece of plywood. I think if I did a large tank like your tanking I would uses 3-4 piles of cinders 4 high for each pile and then top it with a couple 2x10's butted together for the tank to rest on.

 

Well considering we build houses out of cement blocks they will hold a tremendous amount of weight. I even use then under my jack when I jack up my 7500 pound pickup.

 

Won’t the ply wood bow overtime?

 

Plywood does but with the short tanks its not an issue since its more to just level things and not actual support. Now with the bigger tanks you would want to use 2x8 or 2x10 boards which will also bow if not properly supported but will require much less under support.

 

I would think 4x4's or 4x6's wouldn't bow like 2x4's or 2x6's might.

 

Over time any board will especially if it gets damp.

 

The thing I would worry about is sag in the 2x4s. They're intended to bear weight along their length, not across the narrowest dimension. For larger tanks you might want to think about using 2x4s on edge with a piece of plywood laid on top and screwed in place to keep the 2x4s aligned. That would put the weight across the longer cross dimension and also give you a flat surface to put the tank on. I'd think 1/2" plywood would be adequate.

 

Basically an engineered beam design.

 

I’d do 4 by 4’ or 4by 6’s with that size tank. I’m doing a tank and I’m doing 4by 4’s. It will be a 75, two 50’s or a 125. Still deciding. I’m not hung the 4by 4 posts not doing cinder blocks. I don’t trust cinder blocks long term. I’ve seen too many crack in my day. Yes we build houses out of them as mentioned but they are used differently.

 

Building your own engineered beam would be far superior to 4x6's. Basically 2 2x10's then plywood them 2x10's on top. It gets the wood grain running in different directions. Screw it and glue it all together. To biw it all but has to rip the plywood apart.

 

Building your own engineered beam would be far superior to 4x6's. Basically 2 2x10's then plywood them 2x10's on top. It gets the wood grain running in different directions. Screw it and glue it all together. To biw it all but has to rip the plywood apart.
2x10’s won’t fit into cinder blocks though. Many ways to do it. Steel beams are great and can be powder coated.
4 by 4 horizontally should be plenty of strength and estimate to hold over 2 tons per board. And about 9,000-10,000 lbs compression load rating.

https://www.worthview.com/much-weight-can-4x4-support-horizontally/

 

4 by 4 horizontally should be plenty of strength and estimate to hold over 2 tons per board. And about 9,000-10,000 lbs compression load rating.

https://www.worthview.com/much-weight-can-4x4-support-horizontally/

I'm not sure I'd trust the numbers from that article. I've read in several places that a 8' 2x4 will safely support 800 pounds vertically. I've not seen numbers for horizontal support, but given this application is using them with the weight passing through the narrowest dimension, I have to think it's a LOT less than 800 pounds.

Basically an engineered beam design.

I wouldn't have thought to put it that way, but, yeah, that's what it is. I was only thinking plywood on the upper edge, but it would be much better to sandwich the 2x4s between plywood sheets. That would almost eliminate the side load on the 2x4 fasteners and greatly improve the rigidity of the beam.

Even with all this enhancement -- plywood, glue, stainless steel screws -- cost would still be significantly less than commercial shelving capable of safely supporting the same weight. It would be more work and would require tools, though nothing exotic.

 

I don't think the wood matters much ?
If both sides [ all 4 corners] of tank are supported by the block you are set ..Even on a 6 foot tank ..I might put wood over block to make it smooth?
When you talk about how to make an engineered beam what do you think happens when you silicone glass together ?
The bottom of tanks do not bow . That was a PERIOD ..If they did then the caulk would fail ???
My 180 g rest on 3 1/2 inches on each end and has no support in middle ..Only like 10 years so still testing ...

 

I'm not sure I'd trust the numbers from that article. I've read in several places that a 8' 2x4 will safely support 800 pounds vertically. I've not seen numbers for horizontal support, but given this application is using them with the weight passing through the narrowest dimension, I have to think it's a LOT less than 800 pounds.


I wouldn't have thought to put it that way, but, yeah, that's what it is. I was only thinking plywood on the upper edge, but it would be much better to sandwich the 2x4s between plywood sheets. That would almost eliminate the side load on the 2x4 fasteners and greatly improve the rigidity of the beam.

Even with all this enhancement -- plywood, glue, stainless steel screws -- cost would still be significantly less than commercial shelving capable of safely supporting the same weight. It would be more work and would require tools, though nothing exotic.

First I said 4x4’s not 2x4’ and yes I could see 2x4’s supporting that vertically because they will now sideways at the 2” width.

 

I don't think the wood matters much ?
If both sides [ all 4 corners] of tank are supported by the block you are set ..Even on a 6 foot tank ..I might put wood over block to make it smooth?
When you talk about how to make an engineered beam what do you think happens when you silicone glass together ?
The bottom of tanks do not bow . That was a PERIOD ..If they did then the caulk would fail ???
My 180 g rest on 3 1/2 inches on each end and has no support in middle ..Only like 10 years so still testing ...

At the risk of stating the intuitively obvious, glass is not wood. The support structure for the bottom of the tank is also different. It's joined on all four edges to other pieces of glass that transfer the load from the bottom all over the place. Compare this to a couple 2x4s supported only on the ends, with a heavy weight in the middle of the span. Different structure and weight distribution entirely.

With the racks that Cory built, the ends of the tanks are NOT resting on the cinder blocks. The weight of the tanks is supported entirely by the wood. In his setup he's talking about putting two 20H tanks in between each cinder block column. That leaves one end of each tank in the center of the span. Certainly, all of this weight is eventually transferred to the cinder blocks, but it can deflect the wood, particularly toward the center of the span.

There's a shelf in one of my kitchen cupboards that's made of 5/8" plywood. It has had a set of china on it for several decades. There's a distinct bow in the center of that shelf. That's with plywood with alternating grain and maybe 50 pounds of dishes on top. If that was a 2x4 with the weight going through the narrowest dimension I'm pretty sure I'd be seeing an inch or more of deflection. I can't imagine what it would look like if that was 500 pounds of aquarium on top.

First I said 4x4’s not 2x4’ and yes I could see 2x4’s supporting that vertically because they will now sideways at the 2” width.

I understand that you said 4x4s, but a 4x4 is the same as two 2x4s sandwiched together. I found some online references that seem a bit more authoritative than the article you referenced that was focused on backyard swings and tree houses. It claims a load rating of 5000 pounds vertically for stud grade 4x4s at 8 foot length. There was no indication of how much weight it could withstand without deflection when placed horizontally, but I have to think it's considerably less than 5000 pounds.

Based on this, I have to think that what Cory did with 2x4s resting on their wide edge is not a particularly good idea. Over time it's very likely the wood will begin to sag in the center. The fact that the aquarium weight is born entirely by the four corners of the tank actually makes the situation worse since it means the center beam is essentially doing nothing. All the weight is born by the two outer beams.

Creating an engineered beam out of 2x4s and plywood would change this, allowing all three beams to share equally in transferring the load to the cinder blocks. Changing the orientation of the beams so the weight is transferred through the wider dimension also will greatly increase the stiffness of the engineered beam. It will chew up a few more inches of vertical space, but that seems a fair trade to me.

 

I understand that you said 4x4s, but a 4x4 is the same as two 2x4s sandwiched together. I found some online references that seem a bit more authoritative than the article you referenced that was focused on backyard swings and tree houses. It claims a load rating of 5000 pounds vertically for stud grade 4x4s at 8 foot length. There was no indication of how much weight it could withstand without deflection when placed horizontally, but I have to think it's considerably less than 5000 pounds.

Based on this, I have to think that what Cory did with 2x4s resting on their wide edge is not a particularly good idea. Over time it's very likely the wood will begin to sag in the center. The fact that the aquarium weight is born entirely by the four corners of the tank actually makes the situation worse since it means the center beam is essentially doing nothing. All the weight is born by the two outer beams.

Creating an engineered beam out of 2x4s and plywood would change this, allowing all three beams to share equally in transferring the load to the cinder blocks. Changing the orientation of the beams so the weight is transferred through the wider dimension also will greatly increase the stiffness of the engineered beam. It will chew up a few more inches of vertical space, but that seems a fair trade to me.

I agree if they are resting on the wide edge meaning the tank is sitting on the 4”side that’s not a good idea at all.

Also a 4x4 is certainly stronger than two 2x4’s sandwiches together.

Also part of it is how it is put together and designed. I had a 55 gallon tank on a 2x4 built stand for years. Held up great.
If you look at the 125 stand at the LFS you’ll see they are not made with anything thicker than 1/2” or maybe 3/4” wood. It’s all about design.

Again I agree 100% placing any weight on the 4” side of a 2x4 or even 2x6 is a bad idea.

 

This thread is getting deep I made my 55 tank stand out of 2x4's and its held perfect for close to 3 years without a hitch. It's sad that the lumber now a days isn't truly what it should be. A 2x4 is technically a 3.5 x 1.5" same for 2x6's 2x8's and so on..

 

This thread is getting deep I made my 55 tank stand out of 2x4's and its held perfect for close to 3 years without a hitch. It's sad that the lumber now a days isn't truly what it should be. A 2x4 is technically a 3.5 x 1.5" same for 2x6's 2x8's and so on..

Not ruf cut from the lumber yard. Actually horizojtally 2 2x4 sandwiches together will be stronger then a 4x4 since your separating the grain of the wood and it would have to stretch one board and shrink the other.

 

This thread is getting deep I made my 55 tank stand out of 2x4's and its held perfect for close to 3 years without a hitch. It's sad that the lumber now a days isn't truly what it should be. A 2x4 is technically a 3.5 x 1.5" same for 2x6's 2x8's and so on..

To be clear, the issue is NOT the use of 2x4s. You can use 2x4s to build a very strong and perfectly good stand, if they are used properly. A 2x4 will withstand a very large compression load along its length. You can safely figure 1000 pounds per stud grade 2x4 at 8' length. At the 3' length that would be more typical for an aquarium stand the safe load is considerably higher, probably 2000 pounds or more.

If you've seen any of the other threads about building stands from wood, there are several people here who sing in the same choir when it comes to properly engineering such a stand. The weight from the tank should be transferred directly to the vertical 2x4 members without fasteners bearing any of that load. The fasteners (screws) should be used only to hold the pieces together, not to support any of the weight of the tank. So you build a rectangular frame to be under the edges of the tank, and that frame rests directly on top of the vertical 2x4s, not hanging off the vertical members with the weight transferred via the screws. With a 2x4 in each corner, this arrangement will support at least a couple tons.

The issue in this thread is that when the 2x4 is used as a joist, running horizontally with the load applied vertically, the carrying capacity of the 2x4 is greatly reduced. In the video, Cory has a span between blocks of 4-1/4 feet. Southern pine 2x4s on the narrow edge (like they normally would be when used as a joist), on 16 inch centers, would support 100 pounds per square foot (roughly the load of a 20L tank) with a span of 4 ft 7 in. So he's right on the edge of acceptability if the 2x4s were oriented opposite of what he has them. He's also talking about using 20H tanks and up to 55 gallon tanks, both of which would have a higher load per square foot. He's putting too much load on 2x4s oriented the wrong way. It clearly "works" for him, but it's not within limits widely accepted in the construction industry. It's not safe.

Turning those three 2x4s on edge and screwing plywood to the top and bottom would greatly strengthen the structure, bringing all three 2x4s into play as far as support, and making the whole thing a lot safer.

 

Not ruf cut from the lumber yard. Actually horizojtally 2 2x4 sandwiches together will be stronger then a 4x4 since your separating the grain of the wood and it would have to stretch one board and shrink the other.

Even from the lumber yards they are smaller... At least around my parts they are. I bought 32 2x8's and 14 4x4's from a lumber yard my buddy used to work at and their the same size as the ones you can get from Depot. But I can't complain cause the 32 and 14 cost me $60 compared to close to 500 or more from the box stores