When to reinforce?

[MrsE88]

Roughly at what size tank does a person need to reinforce their floor?

If a tank is along an outer wall on the main floor and the stand is wood. Will a 125-150gl be ok? Maybe even up to 200gl?

This is something that always worries me when thinking about going bigger. Since so many here have 120+ Gallon tanks I'd like to know what you all do.

 

[savannah_az]

Well, on the one hand you could do the math, ask experts, etc... and get an exact number. But id like to answer the question with a question, will you sleep at night if you don't?

I have a 210, a bunch of people said id be ok, 2 or 3 said "meh.... maybe" so $100 later I can sleep like a baby.

 

[MrsE88]

That's a good point. I was just wondering if there was a standard of some sort that people go by.

 

[J. H.]

That's a good point. I was just wondering if there was a standard of some sort that people go by.

There cannot be a standard, and if there was it would have nothing to do with gallons. A 8x2 foot 250g tank will be on more beams then a 1 x 2 50g and therefore safer. It also depends on where in the room (how far from a structural wall), the original safety margin the house was built with, and what other things are in the room/house. Also, it can depend on local building/fire department codes for how close to the house's max load you can legally get.

 

[Drstrangelove]

Roughly at what size tank does a person need to reinforce their floor?

Right before it is the size that will cause the floor to warp or collapse. Unfortunately, that depends on that particular floor, exactly where the tank is, how long the tank is there, and what other things are done to the floor.

No one can tell you sight unseen what that number is, because no one can see if there is prior damage (wood rot, termites, water damage, fire damage) or defective work (substandard wood, split wood, intentional cuts, missing fasteners or rusted fasteners), etc. Naturally one can guess, but it's a guess.

 

[MrsE88]

All good points and things I didn't consider.
I'll just have someone look at the floor. I appreciate the responses

 

[Alexxxxsv14]

I have a 135 gallon tank with a 30 gallon sump stand and canopy all in one area. And I live in a mobile home which is not even on the ground it's raised. And everything is fine my floor is normal. At first I was worried but now I regret not have getting a 180+

 

[J. H.]

Right before it is the size that will cause the floor to warp or collapse. Unfortunately, that depends on that particular floor, exactly where the tank is, how long the tank is there, and what other things are done to the floor.

True, but there are two more details involved. 1) Just because the floor is not sagging now, doesn't mean the tank won't cause it to settle faster in that place, causing it to sag more over time. 2) Just because the floor will hold you, your tank and your furniture doesn't mean it will survive your throwing a party and having another 15 people jump up and down on it.
Also, an important part of engineering is overbuilding. Not all wood or steel beams are the same to begin with, and as they settle, they change. Not only that, but carpenters and plumbers very often notch structural beams for their own purposes, further weakening the floor. Because of these reasons, if your floor can hold 3000lbs on paper, it is probably not wise to load it with more than 1000lbs, including people anyway. You want those 'extra' 2000lbs just in case your electrician cut one beam too many, or if you throw a party, or even if the beams just aren't quite up to par after 75 years of holding its load. I know you mentioned these things in your post, but running close to the limit it is okay in a drag race or fighter combat, but not really anywhere else.

 

[Drstrangelove]

So I think we agree that it's complicated. Since I'm not an engineer, I certainly won't pretend to know all (or even most) the factors that make it possible to place a tank on a floor.

However... I think I was talking dead load, not live load. Live loads often exceed structural limits, because wood is a type of material that fails over time from dead loads, but does not often fail from live loads.

Of course, if one puts enough of a load (even a live load) on a floor, it can collapse. That isn't the issue I was discussing.

If you stand on your table for 5 minutes, it might be fine; in 3 hours it might fail. If you put 50 books on a shelf it might be fine for 3 weeks, then fail. That's because wood deflects and then returns to form (like trees), but not infinitely. If the wood is not allowed to return to normal, it will eventually fail or warp.

I've seen loading tables suggest that the load wood can take as a dead load decreases 50% over time. In short, if the wood will fail at 1,000 pounds now, it will also fail at 500 pounds in 12 months, if it's truly a dead load and is never moved.