advice on floor reinforcement

[benzrider85]

So I'm in the process of laying a new hardwood floor in my house and my plan is to upgrade and move my aquarium to a different room. The new aquarium will be a 6' long 110g tank. The wall I'd like to put it on is an exterior wall, but it would be parallel to my floor joists and because its only about 18" wide, it would probably only cross one joist. The joists are 2x10s spaced 16" and the the span is 15' going from the block wall to a large I-beam pictures below. The tank would sit right in the middle pretty much.

I would prefer not to put in any vertical supports because my basement is free of any currently. I have heard about doubling up the joists and joining them together. Is that the best way to accomplish this?

Here is the joist in question on the left and right side.

 

[sleepydoc]

I will give you the same advice I give everyone with similar questions - pay to have a professional structural engineer look at your specific case.

There are many well-meaning people on this (and other) sites. The vast majority of them have no formal education in these topics and no experience beyond "I did it this way and it worked fine." You can take their advice, the problem is, if they're wrong, you're out several thousand dollars.

While you're at it, verify with your homeowner's insurance that you don't need any extra coverage.

 

[daplatapus]

+1
Have a read of this before listening to any other advice:
http://badmanstropicalfish.com/articles/article28.html

 

[sleepydoc]

Yup - Myth #17, way at the bottom is especially pertinent!

 

[ca1ore]

Trouble also is that even if the floor can hold the weight, deflection can result in tank 'settling' in a non-uniform way and breaking the tank. I had this happen with a 125 years ago. Agree with the suggestion about getting a structural engineer to offer an informed opinion. If it were me, on a single joist with a 15' span, I not do it without putting in vertical supports in the basement.

 

[woodnaquanut]

Heed the advise given above!

This looks easy. Since the tank is only supported by one joist, you need more support. If it were mine, I'd:
1. sister another joist onto the existing
2. add two more joists. One in front and one behind the existing. I'd place them to be just under the front and back of the stand.
3. make the sump in the basement
4. put support walls up on either side of tank perpendicular to the joists creating a 'closet' for the sump and extras. This can be finished off to look nice if needed. The basement doesn't look finished at this point so you could just leave stud walls.
5. since you have lots of room in the basement on either side of your new sump (see #3), build racks for QT tanks, refugium, breeding, growout, water storage and other cool fishroom things!

Use LVL lumber for the new joists and get them in tight to the bottom of the sub-floor.

 

[sirreal63]

Heed the advise given above!

This looks easy. Since the tank is only supported by one joist, you need more support. If it were mine, I'd:
1. sister another joist onto the existing
2. add two more joists. One in front and one behind the existing. I'd place them to be just under the front and back of the stand.
3. make the sump in the basement
4. put support walls up on either side of tank perpendicular to the joists creating a 'closet' for the sump and extras. This can be finished off to look nice if needed. The basement doesn't look finished at this point so you could just leave stud walls.
5. since you have lots of room in the basement on either side of your new sump (see #3), build racks for QT tanks, refugium, breeding, growout, water storage and other cool fishroom things!

Use LVL lumber for the new joists and get them in tight to the bottom of the sub-floor.

+1
What I would do, go to a real lumberyard that sells and designs floor systems (I prefer TrusJoist), take the specs of your existing floor and the load you want to put on it (the weight of the filled tank). The software will be able to show the deflection and how to sister the joists with LVL to eliminate the deflection. Keep in mind that you will will probably end up sistering more than just one joist because the load is transferred to the adjoining joists as well. You should be able to do this without a load bearing wall but in case the deflection will still be too great, the wall is still the best solution.

 

[NanoReefWanabe]

you cant simply just put up a load bearing wall and expect it to hold on a concrete floor...you have no idea how thick the concrete is, and if the wall is indeed going to be load bearing it requires a footing...

 

[sirreal63]

Yes, if it is carrying a roof load but that isn't the case here, it will be to prevent deflection of the joists, not support the house. While I don't disagree, a footing would be ideal, even a 4" slab would handle the support of the tank.

 

[benzrider85]

Thanks for the input everyone. I'll will most likely seek some professional advice at least from a contractor. Sounds like if I sister a couple of joists I should be alright. If I can't avoid vertical supports I may ad those as well. As for the sump, I already have it located in the basement on my current tank and it will stay there, so I'll just be supporting the stand, tank and canopy.

 

[sirreal63]

Good, but you want to avoid a post to support the tank, it will require that footing because of a single point load whereas a wall will spread the load out. You should be able to use the 9-1/4" LVL to beef it up without the wall support but until it is loaded into the computer it is hard to say for sure. Deflection of the joists is the enemy here, and I understand wanting to avoid the wall perpendicular to the joists in the midpoint of the load, and with a 110 you may not need it, but if you ever go to a larger tank you may be right back to this point and need the wall.

 

[ca1ore]

It is 'only' a 110 after all. Model it, yes, but is think a couple of LVLs would do the trick. If we were talking a 300DD then different discussion.

 

[NanoReefWanabe]

It is 'only' a 110 after all. Model it, yes, but is think a couple of LVLs would do the trick. If we were talking a 300DD then different discussion.

it may only be a 110g, that is about 1200lbs full, then you have the three or four people standing in front of it, upwards of another 600 pounds..all being supported essentially by a single joist, and the middle of it too...

not only is deflection a major concern, so is fatigue...even though a tank is a live load, it is basically a dead load, as it never really moves or changes weight, fluctuating water volumes and waves make it live...the tank itself is extremely rigid, and that rigidity is dependent on the floor and stand also being rigid, one corner or side of the tank deflecting down 1/2" will put a ridiculous amount of stress on the tank's seams...fatigue will eventually cause the floor to deflect easier and more then before, this same fatigue will also wear away on the silicone in the tank...tank, stand and floor, will show very little signs of fatigue, floor might squeak, stand might squeak, tank wont do anything, until it explodes from failed seams...

finishing the underside of the joists will also help with making the floor more rigid, and it may be as simple as a couple extra LVLs and a sheet or two of drywall, but without someone running the actual numbers i wouldnt risk it...broken tank and lost coral/fish, likely wont cost as much as the repairs to your house...

 

[Mark SF]

+1
Have a read of this before listening to any other advice:
http://badmanstropicalfish.com/articles/article28.html

This was a good read. I wish it went more in depth about multi-story level apartments, such as my building in SF.

Maybe someone can help me figure out what type of flooring I have: A neighbor passed away and the landlord was making improvements on the apartment so that it was acceptable for rent. The door was unlocked and I so I checked out the work, to see what type of improvements I was missing out on :headwalls: One thing that I noticed was very interesting, the floor where they had ripped up the old flooring was cement, and not plywood as I would have expected.

Are the PSF ratings for a floor like this higher? Also, how do I determine which direction the joists run in a building like this. Also, currently, my Nano aquarium is against the outside wall of the apartment complex (should be load bearing), and by bouncing up and down you can definitely shake the aquarium. I am curious if this is because the floor is suspended with cables instead of joists...

-Mark

 

[Pitter98]

Thanks for the input everyone. I'll will most likely seek some professional advice at least from a contractor. Sounds like if I sister a couple of joists I should be alright. If I can't avoid vertical supports I may ad those as well. As for the sump, I already have it located in the basement on my current tank and it will stay there, so I'll just be supporting the stand, tank and canopy.

This will not cut it. At 15' spans you are already nearing the limit of what a 2x10 can span. Per code, residential floors have to be designed for 40 pounds per square foot of load. At 60" x 18" (assuming this is the size), you are looking at 1000 pounds minimum over 7.5 square feet - that is 133 pounds per square foot. Even if you divide it over the the entire length of the joist, you are still looking about about 44 pounds per square foot. And that is not including any sump, people standing there, furniture near it, etc. The center point of a span is also the worst place to put a point load - that is where it is weakest. Your safest bet would be to build 2 walls under each end of the tank in the basement to support the floor - sistering joists will really not help you here. The floor may not completely fail if you don't support it properly, but it will sag, which could cause your tank to crack. Just my 2 cents and hope it helps.

 

[napydred]

now i'm starting to rethink my tank location. I could put a 200 in my living room on a concrete floor and bypass the headache of putting it above my crawl space. But then what do I put in the other living room? Do you think I could safely put a 90 gallon on a floor with the support running perpendicular?

 

[Snausy]

now i'm starting to rethink my tank location. I could put a 200 in my living room on a concrete floor and bypass the headache of putting it above my crawl space. But then what do I put in the other living room? Do you think I could safely put a 90 gallon on a floor with the support running perpendicular?

Get a nice waterfeature trickling wall or something for the second living room. You want more than one tank? How about a nice nano...

I moved into a rental house(a nice new one so I figured good construction) and just set up my 100g with 40g sump in the middle of the wall without realizing that the support ran side to side, I thought they ran out from the wall...I'm too big to fit down in the crawl space(no not fat, just big) so I admit I didn't really check it out. The guy at my LFS said if it was an exterior wall it would hold just fine.

Two year later the front of the tank(away from the wall) was about 1/2" lower than the back. It totally sagged on me and I broke everything down. Luckily it sagged evenly and the tank just tipped forward a little, not twisting at all.

Now that I upgraded to a 300g I just moved it to the garage on the concrete slab to avoid any lawsuits.

Buying a house in a year or so and one of the main things I'll be looking for is a nice place to put the tank.

Good luck!

 

[Pitter98]

now i'm starting to rethink my tank location. I could put a 200 in my living room on a concrete floor and bypass the headache of putting it above my crawl space. But then what do I put in the other living room? Do you think I could safely put a 90 gallon on a floor with the support running perpendicular?

This should be fine. With the joists running perpendicular, it spreads the weight evenly across multiple joists versus putting all the load on one joist. If it is right up against the wall, that will help support it also. Most of the weight of the tank will be a shear load (stronger) instead of a point/bending load from a tank that sits in the middle of a parallel floor joist. I wouldn't worry about your condition too much as long as all the floor joists are in good shape.

 

[napydred]

This should be fine. With the joists running perpendicular, it spreads the weight evenly across multiple joists versus putting all the load on one joist. If it is right up against the wall, that will help support it also. Most of the weight of the tank will be a shear load (stronger) instead of a point/bending load from a tank that sits in the middle of a parallel floor joist. I wouldn't worry about your condition too much as long as all the floor joists are in good shape.

Thanks and I had an inspection done on the home and the inspector recommended putting it on the interior wall with the support running perpendicular