How to beef up joist running parallel to tank?

[West1]

I’m in the process of moving. I had an electrician add two 20amp breakers with GFI’s on each for my Red Sea 525xl. I’ll go under the house tomorrow and take measurements to confirm the joist running parallel to the tank location.

ive been looking for pictures of how to beef it up but I see perpendicular setups or house floor jacks from basements. In my case, it’s on dirt that looks to be as dry as a desert (which is good because it does rain a lot in Idaho).

I was thinking about digging out a 1-2” rectangle and manually mixing concrete about 2-3” thick.
I’m guessing a slab about 60” (6ft) x 24” (2ft) x 2-3” thick. Depending on spacing between joist, possibly sistering 1-2 more joist 8ft long.
Under the sister joist, putting 3 pier blocks and 3 under existing joist.
option B) add sister joist and put perpendicular 4x4’s with 6 pier blocks under the 4x4’s.

my biggest concern is how thick of a slab do I need to do?

anyone with pictures similar to my situation would be greatly appreciated as I am a visual learner.

tyvm!

 

[BrandonS]

A slab would be overkill in my opinion. Digging two hole 6 inches deep. Filling with concrete and setting 2 deck block should be good. Then just run a 4x6 under the tank snug up to the joists on some wood Piers.

Screw jacks are also a good option. Support underneath with some 2x8s as they do for mobile homes and do the same thing with a 4x6.

Pressure treated is always good. Especially with anything on grade.

 

[BrandonS]

This is what I did under my old fish room. This spot was under 6 75 gallon aquariums in a rack. 2 screw jacks made for mobile homes and a 4x6. Pressure treated 2x10 underneath for support.

 

[Weasel1960]

I agree with BrandonS. The 2”-3” thick slab will not be enough th support the floor and will likely crack or shear. Pouring a couple of key spread footings 12” deep adding posts on this and beams as joist supports would be better. A local contractor or structural engineer should be able to do some sketches for you. Don’t forget to talk with your local building inspector also.

 

[West1]

This is what I did under my old fish room. This spot was under 6 75 gallon aquariums in a rack. 2 screw jacks made for mobile homes and a 4x6. Pressure treated 2x10 underneath for support.

Wow, six 75 gallon stacked?
These were parallel to the rack?

A slab would be overkill in my opinion. Digging two hole 6 inches deep. Filling with concrete and setting 2 deck block should be good. Then just run a 4x6 under the tank snug up to the joists on some wood Piers.

Screw jacks are also a good option. Support underneath with some 2x8s as they do for mobile homes and do the same thing with a 4x6.

Pressure treated is always good. Especially with anything on grade.

a slab would be overkill but if I don’t know how to do the math, overkill is the only way to sleep peacefully at night for me haha.

I never thought about Mobil home setups!! I’ll be doing a lot off Google searches tonight, ty!

 

[Weasel1960]

Looks good BrandonS. My other concern for West1 is being in Idaho what is your frost depth if you have a crawl space. Does your foundation all around go to that depth?

 

[BrandonS]

Wow, six 75 gallon stacked?
These were parallel to the rack?



a slab would be overkill but if I don’t know how to do the math, overkill is the only way to sleep peacefully at night for me haha.

I never thought about Mobil home setups!! I’ll be doing a lot off Google searches tonight, ty!

The center of the tanks were directly over the beam. I have the advantage of an older home so the sub floor is 2x6 redwood. But load straight up and down isn't an issue. Most tanks are not more than 2feet deep. So load just a foot each side of center isn't bad.

As mentioned the 2 inch slab wouldn't be thick enough. 6 inches of concrete is minimum to park a car on a slab.

 

[BrandonS]

Looks good BrandonS. My other concern for West1 is being in Idaho what is your frost depth if you have a crawl space. Does your foundation all around go to that depth?

Didn't think of that. I am in california so no frost. I also have an older home, so red wood true dimension lumber and my foundation is 18 inches thick at the base. But I used to inspect mobile homes with screw jacks all the time. Again in california. Ex home inspector. But opinons vary on the profession. Lol.

 

[Weasel1960]

Architectural Project Manager in southern WI. Our frost depth is 4 feet, up north it’s 4’-6” and if crawl spaces are allowed I believe they need to be insulated and heated. Would assume Idaho would be similar.

 

[West1]

I agree with BrandonS. The 2”-3” thick slab will not be enough th support the floor and will likely crack or shear. Pouring a couple of key spread footings 12” deep adding posts on this and beams as joist supports would be better. A local contractor or structural engineer should be able to do some sketches for you. Don’t forget to talk with your local building inspector also.

that’s a good suggestion. I may dig 4 holes approximately 2’ in diameter, 10-12” deep.
2 perpendicular 4x6 @2.5’ long with a 4x6 from each concrete hole creating a T. I’m not sure the name but I’ve seen Simpson brackets at Home Depot where I can connect the T once the concrete dries. I’ll have the 4x6 1/8” longer so I have to force the Simpson bracket in (hopefully that makes sense).
I’ll update thread with pics as I go so others have a visual reference.

 

[BrandonS]

Architectural Project Manager in southern WI. Our frost depth is 4 feet, up north it’s 4’-6” and if crawl spaces are allowed I believe they need to be insulated and heated. Would assume Idaho would be similar.

Do you guys have to dig your foundations below the frost line to prevent uplift?

 

[West1]

Looks good BrandonS. My other concern for West1 is being in Idaho what is your frost depth if you have a crawl space. Does your foundation all around go to that depth?

ive no idea what frost depth is, new resident from sunny California. I did a quick search and found this... 24” frost depth. Does this mean I need to dig 24” minimum with concrete?

 

[BrandonS]

Architectural Project Manager in southern WI. Our frost depth is 4 feet, up north it’s 4’-6” and if crawl spaces are allowed I believe they need to be insulated and heated. Would assume Idaho would be similar.

We have it easy in CA. Slab on grade rules the roost.

 

[Weasel1960]

Do you guys have to dig your foundations below the frost line to prevent uplift?

Top of footing must be 4’ or lower. I think our average frost depth is like 3-9. A couple years ago we went into an abnormal deep freeze and some places with bad soils had issues

 

[Weasel1960]

ive no idea what frost depth is, new resident from sunny California. I did a quick search and found this... 24” frost depth. Does this mean I need to dig 24” minimum with concrete?

Could be but you can always verify with your building inspector.

 

[Weasel1960]

When I start my build this winter I will also be running parallel. My advantage is left side oftank is near center beam in basement, back of tank is at stair wall which turns 90 degrees so right side also supported by stairwall. Hoping my construction buddies at work can verify that all I need to do is add a 2x10 to each I-joist to be safe.

 

[Drewe]

The 525XL is 108 gallons full system total right? That's really not that much, it's anecdotal but I've put around that weight parallel to the joints before, though that was in a 100 year old house with 2x10s and no termite damage so it was very stable/strong. Please note that our situations can't really be compared because I've never seen your joists, but I figured an anecdote could help to ease your mind a tad.

Literally any reinforcements that you do will be enough in my (non-professional) opinion. A bottle jack from Lowes/Home Depot should put your mind at ease.

 

[West1]

I’ve finally gotten around to start the foundation support. Here are some pics of what I’m dealing with. Looks like I just missed the builders concrete slab by 3-4”. Floor joist are I-Beams.
Flash light marks the hole for myself.

The crawl space is an obstacle course and would be extremely difficult to mix and take buckets of concrete down there.

would it sound safe to build a similar 2x4 frame as seen by the builder and run it across 3 floor joist? I was thinking about making 3 of them and placing those on as many pier blocks that would fit. Maybe 4 pier blocks per perpendicular support framing?

all would start on the concrete foundation and transition to the pier blocks

 

[West1]

Opened up my floor where I will pour concrete.

LUCKY ME!! The footing is directly under the right side of the tank! (Tape measure is the 5ft length of the 525xl)

im going to mimic the 16” wide concrete footing and place 2 more 4x4’s between the existing framing. I’ll add a few 2x10’s between the I-Beams for some support.
Hopefully this is overkill.

total water volume forecast is 108gl of salt, 20gl rodi ato.

 

[West1]

Rebar and concrete poured.

time to start patching up the electrical holes for 29 new can lights throughout the first floor!
God willing the family can move in before the month is over! I’ll wait to move the tank to the very last day of our lease, I pray the concrete will be strong enough by then!