New tank and structural support questions

[ShelleyBoston]

Hello there, I am looking to get a 80 gallon tank in my living room which is above a finished basement in a wooden framed townhouse. The house was built around 1982. I am not sure about how far apart the joists are but doing some research online it seems that the going equation is 40 lbs of weight per ft sq. The tank is 48"x 24" or 8sq ft footprint which would result in a max load 320 lbs of weight. So the question is besides will my floor be able to support roughly 850 lbs at what tank size do you start thinking about reinforcing the joist below in the basement?
or am I overthinking this?

Thanks in advanced!

 

[NeverlosT]

Hello Shelley. The need for additional support or not will depend on a few factors:

• How many joists are running under the tank location (are they parallel or perpendicular to the tank?). The more joists that the load is spread over, the better.
• How far is the tank location from a load-bearing wall or a structure beneath the tank? Like is the tank against an exterior wall where it is almost over a foundation wall (as opposed to being way away from a basement wall in the middle of a joint span).
• Your joists are probably 16" on center, I feel like that is pretty normal, but the joist size might be 2x8, 2x10, or 2x12, and that will influence their ability to carry load a lot.
• Your subfloor. Even if joints are strong, if the subfloor is weak (like you have a OSB subfloor under a thin hardwood floor) the tank feet could damage the floor. Then again if the floor is something like tile, or the stand spreads the load over the whole footprint of the tank (instead of small leveling feet) then you would be better off.

The good news: it is very likely that for a 80g tank, your house will be fine with no modifications. I start to get worried when it comes to like 150g and up. Think of it this way. your tank will weigh like ~700lbs, so about the weight of having 4 full grown guys standing beside each other, which you wouldnt worry about.

Hope some of that helps.

 

[ShelleyBoston]

Hi, First off thank you for the reply. I just lifted some ceiling tiles in the basement to see what is under the floor. The joists are running parallel to the tank they are evenly spaced 16 or so inches apart and they are 10-12 ft long 6" x "2 running to a wooden beam that is approx. 8x5 inches, under the beam there 2 that I can see metal round supports running into the cement foundation.
the tank is up against a wall which is at the edge of the house and there are at least 2 of these joists under the footprint of the tank.
I may go for a smaller size I was thinking an 80 gallon all in one Innovative Marine but there is a Lagoon 62 AIO by a different brand so the load will be about 600-650 lbs. Right now I have a 30 gallon in that spot.
I have attached a diagram I made of what it looks like. I hope it is clear.

Thanks

Shelley

 

[NeverlosT]

Any chance you could position like this? It would spread load better across several joists and they would be very strong where they meet the beam.

If the tank has to go in the spot you drew, I think you should either sister two of the joists (add a second joist attached to it), or put another lolli column (metal post) under the joist in the middle of the tank.

80g is right on that borderline of being pretty heavy.

 

[kgstei]

2x6 floor joist doesn't sound right, perhaps you misread the tape measure. Unfortunately the middle of the span with floor joist running parallel is the worst place to put it. If it has to go there and you do have a drop ceiling beneath it depending on how you use that room you could put in supports to the floor joists.

 

[ShelleyBoston]

Thank you for the suggestions. I will have to re-think getting a bigger tank at least for now or until I can get someone to reinforce the floors in my living room area. Now I am worried that my 30 gallon or about 400 lbs of load with the 10 gallon ATO is too much.
Time will tell.

 

[markwilde]

hey shelley im a gen contractor and yup your good ,support against a outside wall with the joists going that way is super strong good luck

 

[markwilde]

my mistake i thought those were 2 by 8 mmmmmm questionable with that load r u in boston what part?

 

[ShelleyBoston]

my mistake i thought those were 2 by 8 mmmmmm questionable with that load r u in boston what part?

I have moved out to Marlborough, I think the joist are 2x6 inches but I could be wrong there is a drop ceiling in the basement and not easy access to the area in question.

 

[Chris.Reef]

I highly doubt they are 2x6 since it was built in the 80s. They are probably 2x8, actual size is 7 1/4. Where you say common wall to the next house are you in a duplex? If it’s a load bearing wall then you should be good.

 

[ShelleyBoston]

I highly doubt they are 2x6 since it was built in the 80s. They are probably 2x8, actual size is 7 1/4. Where you say common wall to the next house are you in a duplex? If it’s a load bearing wall then you should be good.

You are right I just went down there and took another look and the joists are 7.25"x 1.75" the wall is a load bearing wall and is a common wall to the townhouse next to mine.
The frame rest on a concrete foundation and I have a finished basement with a drop ceiling. Under the tank there is a bedroom and this is one of the reasons I am not sure I want to put 2 metal poles under the joists. I guess I would need to get a contractor to come in and take a look and give me some feedback on what would cost to do something like that maybe I can make a closet to hide the stepping post.

 

[kgstei]

You are right I just went down there and took another look and the joists are 7.25"x 1.75" the wall is a load bearing wall and is a common wall to the townhouse next to mine.
The frame rest on a concrete foundation and I have a finished basement with a drop ceiling. Under the tank there is a bedroom and this is one of the reasons I am not sure I want to put 2 metal poles under the joists. I guess I would need to get a contractor to come in and take a look and give me some feedback on what would cost to do something like that maybe I can make a closet to hide the stepping post.

Exactly. You don't need to sister the floor joist. That would be a big project and very expensive. What you need is exactly what you're saying. build a load bearing, wall that is perpendicular to units partition wall in the basement. Double the top plate, pressure treated bottom plate and Put 2x4s underneath the joists and everything is supported. Incorporating it as part of a closet is the perfect way to do things. You do need to have that section supported as over time a static load of 600 lb will cause those floor joists to sag.

 

[Chris.Reef]

you should probably be good if that joist is sitting on the common wall and it’s load bearing. Floor loading is spread out much wider than the footprint of the tank because the flooring and sub flooring will disperse the weight wider. The 40 to 80 pounds per square foot load rating estimate is assuming that the whole room has that weight on it. If you stand on one foot you will definitely exceed the limit if you use that logic. Best practice is always to put heavy objects towards the perimeter walls or where structural beams or walls are located below.

 

[mrcote1]

I had a similar situation when I put my 160 gallon tank on my first floor over my finished basement.

The only place I could put the tank was parallel to the joist so its ony sitting over one joist.

I luckily had a closet right beneath so I just ensured the tank was over the closet and just to be extra safe, i added a lally column and put boards in between the supporting joist and the surrounding joist to help disburse the load.