Crawl space support

[roscoe]

I was wondering if anyone knows whether or not I would have to support my floor from the crawl space for a tank that is 72''lx32''wx24''t (240g) plus sump another 60g, and equipments. I'm guessing it will weigh around 3500lbs. Please help with some ideas. Thanks

Sarang

 

[roscoe]

Anyone with some ideas?

 

[Scooterman]

Hard to say without knowing exactly what you have for structural support, then you need a qualified person/engineer to see what is the supported load already, then see if it could support that much more load. Sounds like a nasty reply but true, I'd suggest getting someone to look at it in person, then going from there, It may be a simple procedure to increase the load bearing capabilities of that area, also you will rest better knowing that you did it right from the start.

 

[roscoe]

True that Scooter. Well I live in a rambler. The wall I am thinking about is about a 25' long wall and about 14' tall. On the other side is my Master bathroom. So I don't think it is supporting to much weight besides that wall right now. I had a 120 in that same place 2yrs ago and it did fine but this is also twice the weight of that too.

 

[harrscars]

If I understand right it is on a inside wall is this the load bearing wall in the house??? Does you're crawl space have you're house footings along this wall??? What is you're floor spacing 12" or 16" by 8 10 or 12's and are you putting the tank crossing you're floor joist's or running parallel with them. If you want to play safe you could box out the tank under you're floor joist's and take the shear out of play. Put you're support's on a concrete slab slightly bigger than you're tank. Cost you about 130 to 150 bucks but it will take the shear load off you're floor. Just my 1 1/2 cents worth. Whats the soil like under you're house?? Loose fill?? Lots of rock?? Dig it with you're hands??

Nice size tank


Mike

 

[roscoe]

I have to go under my house to look to see if the footing is along this wall. I want to put the tank crossing the joist won't that help some with the weight distribution? As for the soil well I live in Spannaway I had a fun time digging up 40 2' deep holes with a 12'' diameter so in other words my house is sitting on top of alot of rocks and boulders lol ( there was alot of sweat digging those holes and not to mention the swearing when I hit a big boulder). How would I go about with building this box in my crawl space you are talking about. What are all the material that i will need to get this done?

 

[MC Lighting]

I am a big fan of overkill myself it is cheap insurance to go under the house and if nothing else use concrete piers and use a floor jack to preload the floor up a 1/4" build a support beam across the floor joist and let it settle in that way as stated earlier you are putting a majority of the weight on the ground and not on the floor structure. And unless the interior wall is supporting the roof they are not usually a load bearing wall therby do not have that much structure below them. As stated earlier though it is a good idea to go under the house and see what you have first.

 

[roscoe]

The wall i am talking about. I beleive it is supporting the roof as it does run across the whole living room floor running up the cathedral ceiling. Well thanks for the input everyone! Now once I get home I will go under my house to see what i am working with (if there is any light left once I get home). Anyone else with any ideas and suggestions? Sorry I just like to collect as much info. as I can b4 taking on a big job like this. Thanks again everyone!

Sarang

 

[dnjan]

Are the floor joists solid wood or TJI's?
As long as you are close to a load-bearing wall, and the tank is perpendicular to the direction of the joists, the primary loading will be shear, not bending. Solid wood joists are way over-designed for shear (bending dominates for all but short spans), and therefore you will be fine.

With TJI's, I would add plywood stiffeners where the joists bear on the supporting wall.

 

[roscoe]

excuse my ignorance what are TJI?

 

[dnjan]

Truss-joists. Those composite wood I-beams.

 

[harrscars]

The box out part I was referring to would be like this. Find your footprint of your tank under the house. Match out your joist size with the same lumber. A 2by8 for a 2by8 or a 2by10 for a 2by10 and so on. Now you would cut and nail in between your joists so they will not flex when you load it with your tank. You would do this for the whole footprint even on the joist on each end. I believe the term would be a sister board. Now you can nail in on the bottom of your joists a box of your tank with the same lumber. Now your floor will not flex or bow with the weight of your tank. Almost done. Take some concrete mix and build you a 2by4 or 2by6 by six inch larger footprint of your tank on the ground in your crawl space. Put some plastic under it so moisture will not wick into the concrete after it is done curing. 7 to 28 days later the concrete is cured and you can put 4x4's or 6x6's from concrete up to your (box out) you built in your floor joist's. Make about a 1/16th larger and pop them in. You will never hurt your floor or house this way. I have loaded 8oo gallons in a 14' wide trailer home (in my trailer trash days) and boxed out the floor with cinder blocks and never had a issue. Actually I think is helped the trailer from rolling over in the Wyoming winds.

Couple days work and you got it.

Mike

 

[harrscars]

I agree with you dnjan but if his floor has any tile or glue in flooring I wouldnt want any joist movement to (pop) the glue in the flooring. My 300 is setting right next to our marble floor and I did not want those joist's to move at all! It was only fun installing it once.

Mike

 

[roscoe]

I am no craftsman I am totally lost here lol.

 

[harrscars]

Sorry didnt mean to do that. Try these see if it makes sense.

Floor joist with a piece I would nail in between them. I used a 2x4 but you would use same size of wood as your joist. You would do this for you entire tank footprint plus one joist to make up your ends. I dont believe your tank will set perfect joist to joist.

At your end joist's you would (sister) your board to it stregthening the end ones and tie it together

Now you can (box) the bottom of your joist's and prevent your floor joist's from flexing under load.

All thats left is your concrete pad on the ground and your supports to your (boxing) of the floor joists.

Mike

 

[roscoe]

Ahhhhh OK Ok now I see! I'm am such a visual person:lol:. That can easily be done. Thanks ALOT!!!!!!!11

 

[dnjan]

I agree with you dnjan but if his floor has any tile or glue in flooring I wouldnt want any joist movement to (pop) the glue in the flooring. My 300 is setting right next to our marble floor and I did not want those joist's to move at all! It was only fun installing it once.

Mike

Good point. If the floor covering would not adapt well to a bit of deflection (like your marble, or ceramic tile), doing as you suggested to stiffen-up the floor would be good.

The worst loading for this case (assuming it is a glass tank) would probably be the weight of the tank plus the weight of all the people helping to carry it across the middle of the room.

One other thing to check for - When the plumbing was installed in the house, did the plumbers happen to run any drain pipes through the joists (rather than under them) where the tank will be going. Holes for drain pipes can significantly weaken joists, and take away that over-design I mentioned earlier.

 

[roscoe]

Wow this is starting to sound harder than I imagined! I havn't gone to the crawl space yet so I don't know whether or not the plumber ran the drain pipes through the joist.

 

[dnjan]

You have gotten some good directions on how to make a suport if it is necessary.

First step, however, is to get into the crawlspace and see what is there. Be sure to take a camera with you!

 

[roscoe]

Will do! When I get home from work it is already dark so this weekend for sure! Thanks guys