placement for 180g tank due to weight

[Iggypop]

Ok so I checked out the crawl space today to look at how the wood joists ran under the house and now I have a question as to what's a better placement for the tank to support weight. Would a 6x2x2 be supported better running perpendicular and in-between the 4x4's that are spaced 5 ft apart ( the 4x4's are held up by concrete pillars/posts) or parallel to the 4x4's and perpendicular to the 2x8 floor joists that are spaced every 16 inches. Here's a quick sketch I drew up to get a quick visual if needed. Any help/advice is appreciated!

 

[Iggypop]

Forgot to add, the left side wall is also a load bearing wall ( has a 9-10ft sliding door cut into it though not sure if that matters at all)

 

[Drstrangelove]

I'll be looking for more input, but I like the second option better assuming that you place the tank astride the area supported by a 4x4 on either side of the tank. The concrete pillars under the 4x4 give them a lot of resistance to collapse.

I assume that you mean that the 4x4 and the 2x8/10 are all directly below the floorboards....no gaps.

1) Is there a pillar under the 4x4 at the load bearing wall? Or is that something like an I-beam and the 4x4 rests on it?
2) I assume the 2x8s are set between the 4x4 with no cuts, i.e., the 4x4 is apparently solid across it's length.
3) are the floor boads above the crawlspace perpendicular to the 2x8s? I'm thinking they almost have to be unless there is something else above the 2x8s.
4) where are the concrete pillars located? My basement had I-beams stretching the width of the house. I'm assuming you either have an I-beam somewhere, or several concrete pillars under each 4x4, possibly just 4-8 feet apart. 4x4s alone would not seem like enough to span the support for a house.

I don't think I like the first option:
1) the tank looks like it would basically be supported by 2x8s or 2x10s set 16" apart. If the 2x8s are simply under the floor boards and between the 4x4s, they are being held by nails/screws with nothing underneath. That would seem fine for a 5 foot span 16" on center for a basic floor. 2x8s should keep the floor solid and supported for 'normal' use. I'm guessing the areas under the kitchen and bathtub have a lot more support than that.
2) running parallel to the floorboards (see item 3 above) is good, but with most of the tank sitting in the middle of the 2x8s, I'm concerned you'll get deflection and warping to the floor. I'd want an engineer to tell me that I could to that safety.
3) in short most of the resistance to the tank in option one are the nails/screws for the 2x8's. As long as they hold, the 2x8's need to keep the floor from deflecting.

I have a lot more belief that the 4x4s sitting on top of concrete pillars (and if so an I-beam) would handle the load. In that case, you are relying upon compression.


However....I'm not an engineer (or even an architect or a builder.) Hopefully this will be corrected by someone who knows.

Many people (me included) will suggest that you have an actual engineer look at the crawl space and advise you. It will cost you some money, but it will probably be well worth it for peace of mind if nothing else.

a) there could be cuts made for wiring that may reduce the load rating
b) the supports may have been added with inadequate or substandard nails/screws
c) there could be aging, rot or damage that only an engineer or architect might see

 

[rodger]

All of the answers are here.
http://badmanstropicalfish.com/articles/article28.html

 

[Iggypop]

Thanks for the input drstrangelove, you're correct the house has a couple sections of I-beams running the length of the house,the section where I want to put the tank doesnt have the same type of i beam though, it has the 4x4's supported by concrete pillars. So are you saying I'd be better off placing the 6ft tank perpendicular to the 4x4's in the 5 ft gap essentially being placed on top of both 4x4's?

Rodger- thanks for the link I came across that site plenty of times throughout my search. After reading through it a couple times I opted to go under and check out the flooring structure to check which way the flooring joists were placed. That's when I came across the 4x4's placed five ft apart in a spot that would be more convenient for the tank to be placed(based on current furnishing of the area). Basically from what I've gathered is the tank should be placed perpendicular to the flooring joists and up against a load bearing wall to be on the "safe side" but wanted some opinions if I'd be okay going parallel to the flooring joists but perpendicular and astride the (2)4x4 beams. The tank would also be placed almost right on top of the 2 concrete pillars holding the 4x4's as well and next to that load bearing wall

 

[jsodwi]

If your worried wherever you want to put the tank, go get 4 2x10s double them up put them under the floor where tank will be and either make some 4x4 posts or get 4 adjustable Lally columns. To support the 2x10s. That tank won't go anywhere. I've seen tank 4 times the size set up that way.

 

[Drstrangelove]

Well, just to be specific, I'm saying you are likely better placing the tank perpendicular to the 2 4x4s while also over top of both 4x4's, but I'm concerned whether or not there is a concrete pillar directly under a 4x4 where the tank will sit. Being close to is not as important as being directly under the tank.

The load will want to push the floor down exactly under the tank. If the floor is directly supported by 4x4s, you want concrete pillars also directly under the tank, not almost under the tank, especially if the concrete pillars are spaced wide apart.

Lally columns (or possibly floor jacks) if they can be seating directly under the tank (whether under 2x12s or the 4x4s is a call I can't make) and firmly seated on the concrete under the house would probably work very well. Large static loads can be handled very well when they are directly over concrete and steel, but not nearly as well when they are directly over just wood. (I assume you have, but I'm not sure if the flooring to the crawlspace is concrete or not.)

You may not need these, but if you do or don't, a structural engineer could certainly tell you.

 

[arodini]

How far out are the concrete posts from the "Load Bearing Wall" side? If they are less than 4' out, I wouldn't worry. Otherwise, I would buy two floor jack posts to put under the 4x4 where the tank sits or at least one under the center of the outer 2x8/10, just so I could sleep at night.



My 180 sits on a concrete load bearing wall (crawl space and basement divider wall) on one 2' end and on a jack post on the other end, with two 2x10's running in parallel the tank's length. The tank has been fine in that position for awhile now, and I actually believe a 360 in the same spot would be fine too. My buddy, who is a structural engineer for commercial building in TX said it's fine, although he never saw it in person.

 

[Iggypop]

Thanks for all the replies guys. So I had my buddy whos a general contractor come take a look yesterday and we were going to add some supports. So before heading out to buy supplies he wanted to take a look. Once under the house he pretty much said the floor would have no problem holding the tank (running perpendicular to joists) as the concrete footings along the wall where itd be against were over 3-4+ft and a still had the 4x4 on concrete piers within 4 ft running parallel and all the wood was in great condition. Basically he said since my house was old it was built on overkill for weight support and I shouldn't worry. So after getting his opinion and from what I've heard from other members I think I'm ready for my tank now

 

[Drstrangelove]

Thanks for all the replies guys. So I had my buddy whos a general contractor come take a look yesterday and we were going to add some supports. So before heading out to buy supplies he wanted to take a look. Once under the house he pretty much said the floor would have no problem holding the tank (running perpendicular to joists) as the concrete footings along the wall where itd be against were over 3-4+ft and a still had the 4x4 on concrete piers within 4 ft running parallel and all the wood was in great condition. Basically he said since my house was old it was built on overkill for weight support and I shouldn't worry. So after getting his opinion and from what I've heard from other members I think I'm ready for my tank now

Great news. I hope to see pictures and hope you enjoy it completely.