tank weight and floor strength

[matt davidson]

Hi everyone!

Ive got a gorgeous 48" x 24" (d) x 30" (h) tank waiting in storage that Ive never had space to fit anywhere. Ive recently moved into a new flat, where there is space but Im worried about the weight of the tank + water. Im in a first floor flat, and part of a terrace.

Anyone have any experience/advice on whether that weight of water would be ok?

Any advice would be much appreciated- Ive got big plans for it this tank.

[MatsP]

If you want a PROPER answer, you need someone that can is a structural engineer (and that can give you a piece of paper where they basically guarantee the load on the floor).

Having said that, you can PROBABLY get away with it. An idea would be to build an extra "stand" that extends out over a larger part of the floor, making a sort of platform. This spreads the load over a bigger area, making for a better "load per square meter" value.

I live in a first floor flat, and I have a total of 1600 liter of water in my 9 aquariums.
Here's a photo of the 7 tanks that are in the living-area [open plan, one bedroom flat] (approx 1150 liter) - I have 2 tanks (450 liter) in the bedroom as well (no photo of that rack).

The rack is 3 meters (10ft) long, the base section is 90cm/3ft wide, so that's approx 1400kg (250kg for tanks and substrate, etc) on a 2.7m2 whick gives about 520kg/m2. That is definitely more than the minimum legal limit according to the building regulations (in scottish regulations I found before, it said 200kg/m2). But most houses are built with a bit more than the minimum standards. Mine is very sturdy concreete floors.

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Mats

[Jaguar]

Just to add, to help calculate, 1 litre of water = 1 kg.

Your tank will weigh around 130kg if 10mm glass is used (10mm should be the minimum for a tank that size)

Water volume will be 520 litres:
Freshwater weight = 520kg
Saltwater weight = 533kg.

To this you need to add any variation for substrate and other decor plus the stand etc.

But I do agree with MatsP, you need to consult a structural engineer to work out the actual weight bearing properties of your floors. I have seen tanks end up in peoples living rooms after starting in a bedroom.

[MatsP]

Right, so the tank weighs around 500kg full of water, and the base-area of the tank is 0.72 m2 - that's 720 kg/m2 of load on the floor.

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Mats

[Bas Pels]

Nobody sane keeps a fish in a further empty tank. Personally, I would estimate the weight of a tank as 1.5 Kg for each liter. that includes the tank itself, the sand, the rock and so on

I myself have 9 tanks, total some 2600 liters, hence approximately 4100 kg on the second floor for some 5 years now. Obviously, my house is made of concrete

[Shane]

Since the original post was in inches (and I refuse to learn metrics) 48" X 24" X 30" equals 149.6 gallons or 1,248 lbs. (89 Stone for Jools) Would you be afraid that six guys (200 lbs each) standing in a small area of your flat would fall through the floor?
-Shane

[Jaguar]

Hi Shane that is US gallons not UK gallons. In UK gallons that 48 x 24 x 30 is 124.5 Gallons if filled to the brim. Just to clarify as Original Poster is in the UK. 1 UK gallon weighs in at 10 pound and 1 US gallon weighs 8.35 pound.

[davej]

This is a great article on floors and what they can support.
http://badmanstropicalfish.com/articles/article28.html

[Jaguar]

Nice article Dave. I didn't know if we were allowed to link to other forums as I know some don't allow it.

[Jools]

Not a problem linking to forums here. My experience (and I've had tanks move the floor nearlry 2" below the skirting) is that it's about spreading the weight. Put a tank on stilleto heel type stand and it will sink into your floor quickly; at the other end of the extreme, put any stand on a steel or concrete base and it'll be fine.

Given your tank, as long as it goes across at least two beams (beams, not floorboards), it will be fine. I had a 48x18x18 in a second floor Edinburgh tenement flat without issue for years.

Jools

[joefish72b]

I can weigh <---(pun intended) in on this subject since I designed my own home. Based on standard building practices the tank would be fine. The only exception would be for cantilevered spaces which are engeneered to handle specific loads. Honestly you would be amazed at how much all your crap in the house weighs. Your tank is not going to fall through the floor unless there is a serious structural flaw. A simple test would be to get 8 people to stand on the spot where the tank would go. If you don't hear wood creaking you are fine.

With that being said if you live in a home/building that is wood frame and maybe an older structure you never know what the previous people may have done. Someone may have moved a line and decided to cut through all the floor joists.

Just for peace of mind here is a simple calculator to figure structural load limits:
http://www.awc.org/calculators/span/cal ... cstyle.asp

[jd_7655]

I'm planning a large 125 gallon aquarium right now. I've done a lot of research.

Having a bunch of people standing on one area of the floor to test it is different then having an aquarium sitting in the same spot for years.

From what I read is the aquarium wont fall through the floor. But over time there is a risk of floor sagging which will cause the aquarium to break.

My tank is going on the main floor above the basement. It will cross 5 joists.

I've read is is best for the aquarium to run the perpendicular to the joist for streinth.

Myself I'm not taking any chances. I'm buying some floor jacks from home depot and reenforcing the floor from the basement.

Heres a video that someone else did.

http://www.youtube.com/watch?v=vW7Ib2MDHYw

[Bas Pels]

Reading the above, I get the feeling those who live on concrete floors think the floor will hold it, while those living on wooden floors are more doubtfull

Matt Davidson, what kind of floor are you talking about?

[MatsP]

Concrete floors are indeed, as a rule, stronger than wooden floors - mostly because the weight of the floor itself is greater and it needs more strength to hold up the middle of the floor. Wooden flors being lighter and more flexible in themselves are not needing to hold up as much weight.

The other thing to consider is where the joists are, how they are arranged in relation to the tank, and how they are supported. You want as many joists as possible supporting the tank.

Also, the shape of the tank matters: a long and wide, shallow tank is going to stress the floor less than a short, narrow and tall tank, will produce a higher load.

In england, a lot of floors are wooden, but in more recent buildings, floors are sometimes concrete.

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Mats

[plecomanpat]

Agreed 8 guys standing in one spot is not the same as having 1200 lbs. there over the course of many years. My 180 gal. show tank sits on a 2x8 on 16" centers floor with the joists running the same as lengthwise of the tank. Only 3 joists are supporting this weight. I installed blocking 5 courses of joists over to tie the floor together which has held for 9 years and has not sagged the floor. The joists are spanning 13 feet. Just saying most people underestimate what floors can hold

[MatsP]

2" x 8" joists are quite beafy for a 13 foot span. I can't find any particular set of regulations, but I'm pretty sure the normal size here in the UK is 2" x 6" (or as we'd say here 6" x 2").

It seems that the "norm" is 1.5-2.0kN/m2 which turns out to be about 150-200kg/m2 - but that is the load the floor should be able to take if you place a load over the ENTIRE floor - so you can have a 15-20cm/6-8" tall tank that covers the whole floor, so not saying you can't go over that as a point-load - and the floor will be stronger near the wall than in the middle.

And clearly, the floor should also tolerate point-loads well over 150kg/m2 - a double-bed that is 6'6"(2m) long and 5'(1.5m) wide with two adults (total weight around 350lbs/160kg), if that's on 4 legs, it would put very high point loads on each of those legs. But over an area of 32sqft (3m2). Bookshelves are another thing that can weigh quite a bit - but they are rarely in the middle of the floor!

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Mats

[crkinney]

Boyoboy I sure am glad you guys and girls wern't around in the day of the water bed .Back in the seventys I filled a king sized water bed on the second floor with out a thougth and it stayed there for fifteen years .My house was built in 1950 ,not much building code back then. The floor did not sag and the bed did not leak .It was eighteen inches deep and sloched around like the ocean .
My advice Just go for it fill your tank and enjoy it,if it falls thru the floor ,heat it and ya got a hot tub.

[joefish72b]

and the floor will be stronger near the wall than in the middle

This is only partly true, there will be less deflection near a load bearing wall but when adding a total load the nuber stays the same. Either way the tank isn't big enough to crash through the floor unless there is a major defect in the construction.

Pretty much everything said here is correct. Just an FYI I used to have (4) 55gallon tanks(two stands 2 tanks each) in my room as a kid. The house was almost 100 years old and we were on the 3rd floor. My ony problem was when I first set up the tanks the floor wasn't level so we had to place 3/4" shims under two legs of each stand.

[matt davidson]

Wow, thanks for the replys everyone. Sounds like the tank should be fine where Im planning to put it. Now Ive just got to get it there... . The floor is wood, but as its a rented flat and the floor below is a different rental i can't get in t check the joists. I dont plan on living here for more than a few years anyway, so should be fine.

Thanks
Matt

[christiansen]

...It seems that the "norm" is 1.5-2.0kN/m2 which turns out to be about 150-200kg/m2 - but that is the load the floor should be able to take if you place a load over the ENTIRE floor - so you can have a 15-20cm/6-8" tall tank that covers the whole floor.....
Mats

i have missed this topic for the start, just finised readding it ! i work in civil engineering and i can confirm what matsp post is true . old buldings used ~150 kg/m2 for live load while the new codes use 200-350 kg/m2 (for usual buildings ) this values are also multiply with a saftey factor of 1.5 !

as for joist , they are usualy paralel with the shortes of the rooms plan dimensions.
where i live wood floors ar not that common (live in a country with frequent seismic activity ), floors are made from reinforced concreet so time and external factors don't influence so much the strenght of the floor like the ones made from wood !

[apistomaster]

Large tanks are normally placed along a structural wall in most multi-story apartments which is stronger because their is less leverage on the connections of the joists to beam or to other vertical structural elements than would be the case if the tank was closer to the center of the room. You mainly have shearing forces but most construction is up to the task. An aquarium may seem like dead weight but for structural purposes it is considered a source of live weight loads since they are never really permanent installations.
In the USA, most wood framed flats have only a thin leveling course of concrete on each floor. This is mostly for sound proofing between units which adds nothing to the bearing capacity. Indeed, this concrete leveling course is ultimately part of the structure's dead weight load. I set up a 125 gal reef tank on the second floor over the apartment manager's unit for 5 years. They became alarmed when they discovered I had this big tank over their dining area and said I had to show proof of water bed insurance. I told them what I did for a living and said I would if their structural engineer was bold enough to contest the opinions of the higher caliber talent I had access to. Never heard from them again. I worked as a structural construction inspector in the metropolitan Seattle area and was constantly dealing directly with structural engineers. Everyone of the engineers I discussed this issue with said the load over the area was within the UBC Code requirements and not to worry. I was a special inspector of reinforced and/or pre-stressed/post-tensioned concrete high rise construction in the area for 27 years. If you live in a modern design concrete high rise building a large aquarium's weight is negligible.

While it was set up it did undergo the stresses of a 5.1 earthquake and for awhile I wondered what would happen as the water was sloshing back and forth. Fortunately the tank was PlexiGlas and had a mostly enclosed monolithic top with just the access openings. That design prevented any water slopping out of the tank but who knows what would have happened if the quake was stronger, longer lasting or both? If you live in earth quake zones III or IV you should take them into consideration. The tank should have resilient connections in all three orthogonal directions to structural members.
This is challenging to do and depends greatly on the type of tank and stand is under consideration.