I'm thinking about using these for floor support

[Dbichler]

Look @redfishbluefish picture is what you want to do just where your tank will be. There’s no need for 6 jacks you’d just be wasting money put it dead center of your tank perpendicular to joists.(same direction as you current form) just where your tank is. I only said us a 4x4 because it’s easier but yes putting other boards together is better.

 

[Dom]

I like this idea with the following exceptions:

1. Don't use 4x4's....the most unstable pieces of wood you can buy, especially at one of the big box stores. Instead make your own cross beam with three two 2x6's nailed (or screwed) and glued together. (In this picture I used four, but three should do it for you.)

2. Straddle at least 3 joists on either end.
3. I think I'm seeing blocking....if not, blocking greatly helps in transferring load to adjoining joists...use it....even up to 5 or 6 joists away!

My compliments; that a really nice job.

Yes, I admit; 4x4s from Lowes is what I had in mind. Before this, I planned on using 2x4s glued and clamped together. It was a logistical decision; I mean, why haul (12) 2x4s when you can haul (4) 4x4s?

To your example: if I "straddle 3 joists", can I center 1 jack under the middle joist, or, must I use (2) jacks, one on each end. 2 jacks across the short span of 3 joists seems like overkill, considering each one is rated for 16,00 pounds.

Do you have a jack recommendation? The space I have to cover is 28 inches (give or take an inch).

 

[redfishbluefish]

You can do it with one jack post per crossbeam, but I'd suggest crossing as many joists as you can. The reason is less likely to seesaw. That is, by only using one jack post, it could act as a fulcrum, and cause for a failure. The more joists you cross, the less likely to seesaw. I hope that's understandable.

Bottom line, if it was me, I'd have two of these crossbeams with a minimum of 3 joists crossed, and two jack posts on each crossbeam.

 

[vetteguy53081]

Currently, my largest tank sits against a wall where the beams are perpendicular to the tank. But I am unhappy with the tank location; it would look better up against the back wall of the room. Unfortunately, this means the tank will be parallel to the beams, and will only have (2) 2x8 beams supporting it. So I want to reinforce the floor before moving the tank.

I've calculated the weight to be not more than 3000 pounds.

I was thinking about using 6 of these, 3 on each 2x8 instead:

Tiger Brand Jack Post JS-36 1'7"-3' (15 Ga)​

Amazon product

Each jack is rated at 16,000 pounds, so ONE would be enough in terms of weight.

I thought six; 3 on each beam under the tank.

Thoughts?

Thank you,
Dom

I used posts on my 660g

 

[JHSteepat]

I ran 2 4x4s perpendicular to the lengthwise-oriented joists under my 150 gallon system.

The 4x4s are underneath the right and left ends of the tank with two 18k Tiger jacks (orange store) for each 4x4. The front jacks are right under a joist just in front of where the tank sits and the back jacks are under the joist closest to the wall. The setup seems very stable a year later. I used concrete pads underneath the jacks.

The comment above regarding cheap 4xs worry me though, but I plan to check on the setup regularly. If I were to re-do, i would look into a stronger material such as both sistering the joists and cross-supporting with glued 2x4s (my crawl space is limited) above the jacks. Probably overkill but I prefer that to worrying.

 

[Dburr1014]

I ran 2 4x4s perpendicular to the lengthwise-oriented joists under my 150 gallon system.

The 4x4s are underneath the right and left ends of the tank with two 18k Tiger jacks (orange store) for each 4x4. The front jacks are right under a joist just in front of where the tank sits and the back jacks are under the joist closest to the wall. The setup seems very stable a year later. I used concrete pads underneath the jacks.

The comment above regarding cheap 4xs worry me though, but I plan to check on the setup regularly. If I were to re-do, i would look into a stronger material such as both sistering the joists and cross-supporting with glued 2x4s (my crawl space is limited) above the jacks. Probably overkill but I prefer that to worrying.

If I remember right, two 2x4 screwed and glued are stronger than a 4x4.
When I did my 150 I used two 2x8. I was going to use 2x6's but my building inspector(my wife works with him) said "if it squeeks, add another plank".
Yeah, no, 2x8 it is. LOL

 

[Dom]

UPDATE:

So, in the interest of placing a bow on this thread, here are a few pictures:

Pic 1 - These are the materials I've prepared.

Pic 2 - The location where the supports will be installed.

Pic 3 - This is the left support installed. The right support is directly behind the old frame which was supporting the old tank location.

Pic 4 - This is a closeup of the installed left support.

I can FEEL the difference under my feet when I walk on the floor. What was once a trampoline is now a basketball court!

 

[Dburr1014]

UPDATE:

So, in the interest of placing a bow on this thread, here are a few pictures:

Pic 1 - These are the materials I've prepared.

Pic 2 - The location where the supports will be installed.

Pic 3 - This is the left support installed. The right support is directly behind the old frame which was supporting the old tank location.

Pic 4 - This is a closeup of the installed left support.

I can FEEL the difference under my feet when I walk on the floor. What was once a trampoline is now a basketball court!

Nailed it!

 

[Dom]

Nailed it!

Is that a pun?

They span across 4 beams.

 

[Dom]

@Dburr1014
@vetteguy53081
@redfishbluefish
@Dbichler
@exnisstech
@phillyb614

So, the posts are in place and I've relocated the empty tank to its new spot. Today, I leveled the tank.

Left to Right, the bubble on the level is dead-center. But the tank does lean forward about 1/4". Right now, the tank is level. But I'm concerned about having to place all of these shims under the supports of the stand.

Thoughts?

Here are the pictures:

 

[vetteguy53081]

@Dburr1014
@vetteguy53081
@redfishbluefish
@Dbichler
@exnisstech
@phillyb614

So, the posts are in place and I've relocated the empty tank to its new spot. Today, I leveled the tank.

Left to Right, the bubble on the level is dead-center. But the tank does lean forward about 1/4". Right now, the tank is level. But I'm concerned about having to place all of these shims under the supports of the stand.

Thoughts?

Here are the pictures:

These wedges which I use are great for leveling but not support. I use a whole sheet of plywood for reinforcement and weight distribution but if there is a basement - Jack posts are best

 

[redfishbluefish]

I had a similar problem....leveled left to right, but leaning forward by about 5/32. What I did was rip a 5/32 strip off a 2x4 and then used a car jack with some scrap 2x4 to jack up the tank and stand and slide in the long "spacer" under the front of the stand. The 5/32 spacer is on the floor, right in front of the stand, ready to slide it under the stand once it's jacked up.

 

[BeanAnimal]

Dom. Do me a favor, can you draw a simple top down view of the floor... where the tank is, where the current support is and where the tank is going?

Load bearing walls shown and approximate distances. Pen and paper will be fine, nothing fancy.

 

[BeanAnimal]

never mind - I missed a whole page somehow.

 

[Dom]

I had a similar problem....leveled left to right, but leaning forward by about 5/32. What I did was rip a 5/32 strip off a 2x4 and then used a car jack with some scrap 2x4 to jack up the tank and stand and slide in the long "spacer" under the front of the stand. The 5/32 spacer is on the floor, right in front of the stand, ready to slide it under the stand once it's jacked up.

Nice idea... if you have the same amount of space across the entire bottom. Looking at the photos, the space gets larger from right to left.

 

[BeanAnimal]

The shims will be fine, but they can point load the stand and subfloor so the count needs to be increased to spread the load. Going to assume that is 3/4 T&G. What is under it, pine planks or plywood?

 

[Dom]

The shims will be fine, but they can point load the stand and subfloor so they count needs to be increased to spread the load. Going to assume that is 3/4 T&G. What is under it, pine planks or plywood?

Correct. 2 1/4" tongue & groove.

Under that is 3/4 ply. Then the 2x6 joists (which run left to right under the floor. Under that are the floor posts. There are two; one under each end of the tank running front to back. Here is a pic:

 

[JayM]

Hard to tell how consistent the gap along the front is on my phone, but I’d suggest maybe transferring the gap to the rear and trimming the bottom of the stand to fit the slope of the floor.

If that doesn’t sound like a pleasant task, a full strip of appropriate thickness wood across the entire front would work well.

You might even be able to crank up on the jacks and take out some of the sag.

@Dburr1014
@vetteguy53081
@redfishbluefish
@Dbichler
@exnisstech
@phillyb614

So, the posts are in place and I've relocated the empty tank to its new spot. Today, I leveled the tank.

Left to Right, the bubble on the level is dead-center. But the tank does lean forward about 1/4". Right now, the tank is level. But I'm concerned about having to place all of these shims under the supports of the stand.

Thoughts?

Here are the pictures:

 

[Dom]

Hard to tell how consistent the gap along the front is on my phone, but I’d suggest maybe transferring the gap to the rear and trimming the bottom of the stand to fit the slope of the floor.

If that doesn’t sound like a pleasant task, a full strip of appropriate thickness wood across the entire front would work well.

You might even be able to crank up on the jacks and take out some of the sag.

The gap gets wider as you go from left to right. If the space was even, then I would do what @redfishbluefish suggested; rip a 2x4 to size and slide it in.

I thought about cranking up the floor post on the front left, but when you install posts, you aren't supposed to crank them; just bring them up to the joist and set them firm.

 

[BeanAnimal]

You can crank on them a good bit. Just don't lift the joists off of the bearing wall and don't crack any the drywall.