View Full Version : How much can a 4x4 support in weight?

the rock...beauty
12/21/2003, 03:23 AM
I am in the process of designing a stand for a 220gallon glass tank. Th dimensions are 72 x 30x 24. I was wondering how much a 4x4 can support?


12/21/2003, 04:53 AM
I'm not exactly sure how much, but depending what type of wood you use, it could be alot. I sell bldg materials in Fla and they use yellow pine to hold up everything in new houses from porches to floors, which has to support at least 35Lbs per sq foot.

12/21/2003, 07:10 AM
i built my stand from 16X8X4 solid concrete block
on the ends, then used 4X4's to brace the tank bottom,
then 1" yellow pine boards to support the entire bottom.
wrapped it all with 3/4" oak plywood.
i may have gone overboard, but i build to last :D

Bass Master
12/21/2003, 10:37 AM
ever seen houses on stilts?

12/21/2003, 10:49 AM
I know that a 2x4 can support over one ton so I'd assume that a single 4x4 can double that.

12/21/2003, 11:15 AM
I think it would be overkill to use 4x4's. You can do the same thing with 2x4 and save some valueble space. Go to the GARF site and look at their DIY stand. Just modify the calculator to fit your dimensions.

the rock...beauty
12/21/2003, 11:28 AM
Thanks for all the replies. I built a stand for my 125 out of 2x4's wrapped in plywood. My question is, 4x4's in the corners...can I get away with doing that. The tank is all glass and weighs a lot and then calculating in for live rock, etc. Please advise. Thanks.

12/21/2003, 03:34 PM
a few quick examples

in psi, for dry wood
</tr><tr><td>douglas fir</td><td>1668</td><td>625</td><td>1700</td></tr>
<tr><td>yellow pine</td><td>1150</td><td>420</td><td>900</td></tr>
<tr><td>E. white pine</td><td>1438</td><td>335</td><td>1200</td></tr>
<tr><td>idaho W. pine</td><td>1006</td><td>335</td><td>1050</td></tr>

remember when doing your math a 2X4 is not 2" X 4" the same goes for a 4X4

12/21/2003, 03:49 PM
Also remember it has a lot to do with the quality of the wood. Watch out for the pervasive knots that are in most of the lumber you get now days. The other thing to remember is that it has everything to do with run. You have a six foot tank and you DON'T want it to be sagging in the middle. Make sure to work in appropriate vertical supports along the 6' even if the 4x4 will hold the weight.

12/21/2003, 03:53 PM
I have a 125 AGA, and i built it out of 2x4 's with the plan from GARF. Only thing that I changed is that I turned my supports (looking at the smaller side as opposed to the wide side) so that they went from front to back, so that they would catch the bottom side of all my cross braces. I have 1\4" oak finish plywood on the outside of that for the skin. I have no doubt about the strength of this stand. I would use it to support my UPS truck if i ever had to do it.

12/21/2003, 11:29 PM
I used 4x4's on the back corners of my stand along with a 4x4 header to keep the back of the tank completely open for access to the sump. The front and sizes are 2x6 (actually it is in the wall so the whole wall is 2x6). I think you will be fine with 4x4's in the corners.

the rock...beauty
12/22/2003, 02:41 AM
I figure I will go with something like 4x4's on the corners and a couple in the middle for support. I have not drawn up a design yet but will during xmas.

By the way. Does anyone have pictures of their stands built with 4x4's? Thanks.

12/22/2003, 02:34 PM
You also have to consider this...

I have seen 3/4" thick MDF holding up 265 gallon tanks.

I sure as heck would not trust it, but the tank has been there for at least 4 years with no problems.

Also, a lot depends on how you put the boards together, which is clearly illustrated by the chart from rsman .. think about it, and design the stand properly so it can support the weight no problem. A poorly built 4x4 stand will probably not be as strong as a well built 2x4 stand.

12/22/2003, 03:58 PM
I used 4x4 in the corners & middle support on my 125g, then added 2 additionla 2x4's in the middle as additional support. I used 2x6's for top, bottom & side rails for the tank to sit on. Topped off with 3/4 plywood. I will NEVER have to worry about my stand failing. Well worth an extra $20 IMO

12/23/2003, 09:05 AM
i have just built a stand for a 55 gallon long tank i had used 2X4s and it is doing just fine. you just have to remember to put support beams on the four corners and in the center. all the weight is spread out across the whole project. if you can i would suggest putting stiraphome <- that has got to be spelled wrong. all over the entire top to help spread the weight around and if you make about a 1 inch lip on the top you wont have to see it. this is probably commen sence but just remember if you have carpet that you wont be able to pull open the drawers so put them up about a inch or more.

12/23/2003, 11:42 AM
Here's my 180g stand I built with 4x4 posts. I figure your 220g on 4x4 posts built properly should be no problem.




the rock...beauty
12/23/2003, 12:17 PM

Are all the legs on your stand built like the one in the first picture? Also how did you secure the legs to the bottom and top? Last time I did it I used the metal braces. In my opinion I think that it is the strongest but I would like to get other opinions and ways of going about it. Thanks.

12/23/2003, 12:22 PM
a lot

12/23/2003, 12:23 PM
I just built a deck that has a hot tub on it, prolly 7-8 thousand pounds total on it with 6x6's

12/23/2003, 01:32 PM
I only notched out the middle portion. Figure it would give the stand more stability. As for the other question. I had to use really really long screws (8"++). HD didn't carry what I needed so I had to shop elsewhere. I did add some metal L brackets and believe me, my stand is strong as heck. Only downside is that it weighs quite a bit.

Be sure to glue everything down as well. If you want the best strong glue, use Gorilla glue I think it's called; available at HD.

the rock...beauty
12/24/2003, 03:03 AM
Fish a holic,

Thanks for the information about your stand. Could you post some of the finished stand? Im just trying to gather ideas of ways to make the stand.


12/24/2003, 11:41 AM
The stand isn't quite finished just yet. LOL I haven't had the time to wrap the thing in maple plywood just yet. Perhaps in the next 2 weeks when it's done, I'll post pics.

Another Salty Dog
12/24/2003, 11:51 AM
4X4s on the corners with 2X6 rails at the top and 2X4 Rails at the bottom where the shelf will be is MORE then enough to support 125 Gallon tank. My father in law was a cabinet maker and he built the frame for my last tank that way. The top edge of the 2X6 should be notched so the tank will fit down into it by about 1 inch, the tops of the legs should be dadoed to except the 2X6s. the bottom shelf gets the same treatment. That way the load goes straight down through the 4X4s. He built it out of ceder because of it's natural resistance to water. Be sure to build it with the crown of the wood on the up side. The weight of the tank will flaten them out .

the rock...beauty
12/24/2003, 11:58 AM
Another Salty Dog,

My stand for my 125 is built with 2x4's. I figure for a 220 all glass building the stand with 4x4's and 2x6's will be sufficient. Let me know what you think...Thanks for your input.

Another Salty Dog
12/24/2003, 12:14 PM
Rock Beauty. Yes that will also do the job. Be sure to dado the joint work if you can and use WATER proof carpenters glue ... clamp and add a few screws when the glue is set. Keep in mind that all the weigh of the tank is supported at the corners so be sure to build it SQUARE as will. if you are going to add panels to the finished frame they will add strength as will .. not only straight down to the floor but also diagonally so the stand will stay square. In new construction 2 2X4s nailed to together creates what is referred to as a P4 post and they will tank a LOT of weight when the load is from directly above. I will post a pic soon if I can find one of the 125 stand that I refer to above.

Another Salty Dog
12/24/2003, 12:52 PM
I could not find any PICs of the stand before the finish panels went on but here is a fast drawing that I hope is of some use to you.

the rock...beauty
12/24/2003, 01:11 PM
Thanks for the pictures Another Salty Dog...they do help.

12/25/2003, 05:56 AM
Originally posted by TheUPSguy
I think it would be overkill to use 4x4's. You can do the same thing with 2x4 and save some valueble space. Go to the GARF site and look at their DIY stand. Just modify the calculator to fit your dimensions.

How do i get to the GARF site?

12/25/2003, 06:07 AM
The GARF website:


12/25/2003, 06:31 AM

Another Salty Dog
12/25/2003, 07:16 AM
yes 4x4s are pretty big for this job. However they are easer to work with and handle for do it yourselfers. When it's all said and done the stand could be made out of 5/8 inch plywood or MDF board as long as it is put together properly and the weight to directed straight down to the floor through the gables. One need only look at how a kitchen cab is made to see this effect. If you do build a stand with the smallest dimension wood that will do the job you best be sure your skills and technique is completely correct.

12/25/2003, 08:29 AM
i built a stand for my 125 out of 2X4 & works fine :)
however since this hobbie is so addictive i ended up selling my 125 & buying a 210 just the tank i dint want to build a new stand so since the 210 was 6f by 2f i ended up adding to the back with
2x4 & the tank is holding up fine,my tank is on a floor slab so no need to worry about my floor saging :)

12/25/2003, 08:30 AM
this is with the new tank

12/25/2003, 08:31 AM
& another shot :)

12/25/2003, 08:32 AM
here is what it looks like & yes i still have to finish the canopy maybee now that Xmas is over :)


Another Salty Dog
12/25/2003, 08:46 AM
That's a nice job and it is put together well which is sooo important. Your DIY skills are high. Well done

12/25/2003, 08:54 AM
thanks rob if u want to see how i built it check this out :)

Another Salty Dog
12/25/2003, 08:59 AM
I bet DIY saved enough to pay for your new saw :-) I also have a 10 inch saw and would be lost with out it.

12/25/2003, 09:15 AM
AHHHH yes tools are a most with out the proper tools i could not have done this i used a 10inch table saw,10 inch mitter saw,router,10 inch hand saw for now i wish i had other tools but with in time we know how expensive this can get & santa just bought this for me :D

Another Salty Dog
12/25/2003, 09:27 AM
Yes TOOLS and you are lucky because tools are a lot cheaper in the states then they are up here :-( But I do have a pretty good collection on the go. It's a must to be a handy person in this great hobby of ours. SO final note to DIYers buy tools with the cash you save

12/25/2003, 09:40 AM
can u get them online or is it still expensive?
i just noticed u where in canada :)
i dont mean to barg about tools i just want to make sure that DIY reefers know what they need maybee i shoulnt have posted that xmas present i got:cool:
J/K it's all good i was reading this thread where this guy had so many tools to work with he had & awesome shop
little by little when u become a homeowner u just have to have this tools around.

12/26/2003, 02:13 AM
Here is a little site i put up for my stand using 6 4x4's for a 150G tank.


The thumbnails don't work, but you can get alot out of reading the text. If you need full res photos, PM me your email address and i'll send em over.

12/26/2003, 07:54 AM
If you look at home building, the codes generally allow a 2 X 4 wall for a one story application. If two story, the lower walls will be 2 x 6 and the uppers can be 2 X 4. These walls support the whole home, contents, structure and roof.

Even 2 x 4's are over kill for most tanks. But they are cheap and available. What really provides the strength in a wall is the sheeting. If you build a tank stand out of 3/4 ply and use 2 x 4 framing, it will hold far more than a standard wall because it is only 3-4' tall.

4 x 4's make great posts and barn supports, but they are total overkill on a tank stand. The wall that is below the tank is probably 2 x 4 and carriers the tank load along with a share of the house. It will fail long before the 4 x 4. Its like holding up you pants with steel cable and winch.