Will my countertop support more weight

[agusf]

Hello all,

I've been running a 20 gallon / 75 liter tank on my kitchen countertop for several months now fine, but I wanted to upgrade to a larger 36 gallon /136 liter tank, since the space to accommodate it is available in that spot. I already acquired the 36 g tank, but haven't swapped them out yet. My family members have expressed concern as to whether the countertop can even take the weight of the tank once filled with substrate and water. The countertop is made of a sort of resin, one single slab. I've taken some photos and attached here to show what it looks like, including from underneath the surface (with drawers opened). Should I be concerned about the countertop supporting that size tank & try to distribute the weight more evenly? I've thought perhaps I could actually install some planks/supports underneath the countertop as there does seem to be space for such supports to be installed in the gap above the drawers that would not interfere or take away from the drawer space. Alternatively I could just place the tank itself on a plank that spread out more along the whole surface of the countertop, as without anything in between, the tank would distribute all of the weight on the outside rim.

above picture shows current 20 gallon tank. notice beneath the counter there are two cabinet openings, one a drawer that is partially opened already and another a cabinet (closed). The following two pictures are different angles of the drawer underneath the countertop, which is showed partially opened in the first image.

The following pictures show the inside of the cabinet with a door that opens sideways, which is shown closed in the first photo.

Any input is appreciated. Happy New year to all and may 2021 be better.

 

[eatyourpeas]

@Naterjm is the construction expert, so I have summoned his attention. I would add the extra support just because stone has no flexibility and the last thing you'd want is for your counter to crack due to an uneven load.

 

[raylove]

I would think it will be fine because the load is actually being taken by the vertical boards. If I look at the cabinet that came with my 360lt tank, the boards are thinner than what yours appear to be, but the same applies. If there was a long span between the vertical boards and the tank sat on a horizontal board but NOT directly over the verticals then you would have to think about the strength of the horizontal board too, but that doesn't look like the case here.
Also, 136lt of water will weigh about 300 pounds. The tank itself will weigh something as will rocks and gravel, however, the latter will also displace some water. So, basically, the completed tank will weigh the same as about 2 medium sized men. So, if you are happy that 2 men could sit on the counter without breaking it, you should be confident that it will support the tank.

 

[itiwhetu]

I think it will be fine. the weight is spread over a a large area

 

[WhistlingBadger]

Probably OK. But wow, I'd want to go for more than probably, since the stakes are so high. @raylove is right about the weight; you'll have about 10-15 pounds of weight per gallon (depending on your setup). If it were me, I would go beyond that, though, just to have a good margin of error. Get three adult humans to stand close together on the counter for a few minutes. (I recommend asking good friends who won't think you're some sort of weirdo, or better yet, very good friends who already think you're a weirdo and love you anyway)

If it holds up OK with no creaking or other scary stuff, you're probably fine.

I cringe to think about the 20 gallon I set up when I was a kit, on a tall, rickety dresser on wheels. Had it there for years, and I can't believe it never collapsed...

 

[FishGuest5123]

If cabinets are good, wood cabinets then it should be safe. If particle board, then no.

 

[raylove]

This is picture of the cabinet that my 260lt came with. The wood is half inch thick and the weight is spread across 4 vertical pieces. There are then 4 wooden feet, two under each vertical, which ultimately take all of the weight. Mine will weigh twice what yours will.
Although the wood feels fairly solid, I believe it is probably fibre board - all my previous tank cabinets have been.

 

[StevenF]

36gallons of water is 288 lbs. So ask someone sit on another portion of the cabinet with no weight on that spotted then add more people until the weight is about 300lbs. Or if you have a gym weight set use that. If you don't add any larger rocks and limit the substrate to only 2" deep your tank should be close to 300lbs.

 

[FFGuest6357]

I am NOT an expert in construction, although I do appreciate the shout out.

im not an engineer either. But I do have some insights into this. The counter top you have is made of marble? Or granite?

beautiful finishes and will have plenty of compression strength, however their tensile strength is going to be pretty low, especially at that thickness.

weight capacity is formulated based on static and dynamic weight load, static essentially being the weight the floor or surface is always under pressure of and dynamic will be any forces that are temporarily being put under.

to assume that any countertop would be built with a static weight capacity of a tank that size would be foolish. If that tank was too apply pressure on the wrong spot, it would snap the material like a twig.

In this regard, having friends sit on the counter to see if anything creeks or groans is futile, other than to let you know it’s definitely not worth putting that much weight there. It is not a good test to see if you should add more weight.

you need to be aware of the material your cabinets are made of. If it’s particle board, then I wouldn’t be comfortable with the current 20 gallon you have there, especially because it’s in the kitchen where water is always present.

depending on how much your house has settled, sometimes kitchen installers will shim counter tops level, increasing likelihood that you countertop will have very precise pressure points. So make sure you get a good look at see that the counter top is resting completely on the tops of every cabinet underneath.

If the structure of cabinets is made of particle board, I would say no way to a bigger tank, and I would add supports to hold what you have and distribute the weight.
If it’s made with real wood, I would add supports anyway.

A lot of replies have mentioned “probably okay”, but in my line of work, probably doesn’t cut it...

 

[itiwhetu]

Maybe have a look at the Juwel Aquarium stands and compare. I have a Juwel Aquarium 20 g the stand is all particle board.

 

[FFGuest6357]

Also very important to check level on the countertops in all directions.

That is a LOT of weight to be putting on a kitchen counter top. In any situation.

doing anything you can to add support is cheap insurance against a lot of issues.

mad I can’t be there to inspect the exact materials and setup of your counter top, I don’t recommend this upgrade. I will officially recommend you find an alternate space for this tank.

 

[Kyle E.]

And you say your not an expert???

 

[agusf]

Thanks all for your replies.
I had a go at dismantling the drawers and cabinets underneath the countertop. Those are definitely not what are supporting the weight on it, the countertop seems to be just fixed onto the wall behind and sticking out perpendicularly from it. The board inbetween the cabinet and drawers does (almost) go from floor to countertop, with just some legs that support the bottom board at the very bottom, but even if that was helping to support weight I would discount it entirely due to the aforementioned and also because it is [fibre] board.

Good news is after dismantling it some I don't think that it is impossible or irrational to add some support. I will provide in a consequent post some diagrams I threw together demonstrating what the space looks like and what additional support I could plausibly add, drawing from my own brainstorming.

So If there is absolutely no way to reliably improve support then I will not attempt it at all, and reluctantly see if I can find another spot to have the tank. I am reluctant to do so because we live in an apartment, not quite small, but space is not abundant and there is already a great deal of design and purpose inherent in where everything else is situated. Essentially if an aquarium is to be found in this household, there isn't a better ( or much more anyways) of a space for it than there. But more likely so, if more support can't effectively be added, I might just leave it as is with the 18g aquarium

 

[agusf]

The following is a 2-dimensional cross section from within the drawers; the cabinet (to the left of the drawers) is more shallow with more empty space between the wall and the false back panel.
(edit: disregard 'granite', its made of a resin)

Below are some ideas I had for improving support, both behind the drawers and the cabinet. i.e. installing some direct supports/columns from ground to countertop (in black), or some metal brackets(grey) mounted onto the metal beams in the wall behind the countertop.

If the clearance given by the negative space between the false back panel and the wall/ or the gap between the bottom of the resin countertop and the panel is not enough, I could probably get away with doing away with a couple inches of the false back panel. Also,I don't think I can screw into the bottom of the resin countertop, but I could possible screw into a wooden/other board which then has the countertop rest upon it (in purple):

Here is what the cross section would pretty much look like behind the cabinet, and how I would think to approach adding support there:

And maybe also add a wall mounted bracket like behind the drawers.

Since this is only 2-dimensional, I should mention that of course the idea would be to have 2 or three wall mounted brackets and/or columns, i.e. in the 2nd/3rd diagram. I don't know how many metal beams are in the wall behind or how far apart, as I wasn't quite able to get to it. I will contact the cabinet manufacturer/installer this week to understand how to dismantle the back of the drawer / take out the false back panel, and once I do that will use my beam finder tool to report that. In the meantime, please continue sharing your thoughts and evaluations.

 

[agusf]

The counter top you have is made of marble? Or granite?

Well actually I thought it was some super glossy granite but apparently it is just a type of resin.. I've just asked a family member for the contact info of the contractors who installed it (recently) so I should be able to get back to you on the countertop's specific properties.
Edit: from one of the photos in my first post, I looked up compac and found us.compac.es - seems thats the company that made the resin. They do provide figures for the flexural strength of their many surfaces, so I might try contacting them directly giving them the numbers printed on the underside of the surface to get those specific properties.

beautiful finishes and will have plenty of compression strength, however their tensile strength is going to be pretty low, especially at that thickness.

So if I understand correctly.. good resistance against direct force but not against rotational force, i.e. really heavy weights put on the opposite end of the surface from where it is mounted onto the wall

In this regard, having friends sit on the counter to see if anything creeks or groans is futile, other than to let you know it’s definitely not worth putting that much weight there. It is not a good test to see if you should add more weight.

I figured so

you need to be aware of the material your cabinets are made of. If it’s particle board, then I wouldn’t be comfortable with the current 20 gallon you have there, especially because it’s in the kitchen where water is always present.

its fibre board - although I don't think this is at all the primary structural support, rather than whatever is holding onto the countertop in the wall. Understanding that better seems to be crucial.

depending on how much your house has settled, sometimes kitchen installers will shim counter tops level, increasing likelihood that you countertop will have very precise pressure points. So make sure you get a good look at see that the counter top is resting completely on the tops of every cabinet underneath.

When I just now looked underneath the part of the countertop where my current 20g tank is, I did not see any thin pieces of wood (which I take are what 'shims' are).

If the structure of cabinets is made of particle board, I would say no way to a bigger tank, and I would add supports to hold what you have and distribute the weight.
If it’s made with real wood, I would add supports anyway.

Well, I'm convinced the fibre boards directly beneath the countertop are more for show than structural, and the structure and distribution of weight lies within the wall. So once I get a better look at that, I will report what I find.