Enforcing floor

[christwendt]

Hello. I have added sister joists 3 feet long coming off load bearing wall. The tank is 2 feet from load bearing wall towards middle of room so the sister joists expand past the tank. I then bridged between the joists. I’m wondering if I need to add a 4x4 across the 3 joists and jack up then keep the jack in place. I would prefer not to do that so there isn’t a floor jack in the middle of basement. Tank is 140 total gallons on load bearing wall.

 

[threebuoys]

A true sister joist needs to be supported by a post or pillar (or a girder resting on a wall ,post, or pillar at each end. ) Generally, a sister joist runs the full length of the original joist if the purpose is to maintain or increase the load.

 

[christwendt]

A true sister joist needs to be supported by a post or pillar (or a girder resting on a wall ,post, or pillar at each end. ) Generally, a sister joist runs the full length of the original joist if the purpose is to maintain or increase the load.

Yea I could not get the entire joist length in the area. It would have been a disaster with the air duct going through it. I did not know a true sister needs to be supported by a post or pillar. Would I want one or two pillars if the tank spands 3 joists ? Also since I didn’t run the full length joist did it make it pointless ?

 

[redfishbluefish]

I'm confused??? You are saying the sister is only three feet long? Just ending after three feet from the sill??? When you sister you want to run from sill to sill or sill to support beam. That said, I'd double bolt ever 24 inches and add blocking/bridging even to other beams that are not sistered. Blocking transfers load to adjoining beams. 140 isn't that over the top as far as weight.

 

[exnisstech]

From the pics it looks like your right next to the center beam? I'm no engineer etc but I kept a 180 gallon in the same spot for years and your house looks to be built a lot sturdier than mine

 

[christwendt]

I'm confused??? You are saying the sister is only three feet long? Just ending after three feet from the sill??? When you sister you want to run from sill to sill or sill to support beam. That said, I'd double bolt ever 24 inches and add blocking/bridging even to other beams that are not sistered. Blocking transfers load to adjoining beams. 140 isn't that over the top as far as weight.

Yea I’m saying that lol. Based on your response I must need a support beam. I’m not running sill to sill. I worried there was no support adding to the sister joist without a column. I did add blocking but not much. I’m trying to prevent cutting the entire ceiling. I’ll add a column. My tank is still wobbling tho so I think it’s my stand..

 

[christwendt]

From the pics it looks like you’re right next to the center beam? I'm no engineer etc but I kept a 180 gallon in the same spot for years and your house looks to be built a lot sturdier than mine

Yes tank is 3 inches off center beam from load bearing wall. I think structurally it’s strong enough. I’m realizing now my wobble isn’t from my floor joists.. I think it’s my stand and I shimmer wrong or something.

 

[BeanAnimal]

I'm confused??? You are saying the sister is only three feet long? Just ending after three feet from the sill??? When you sister you want to run from sill to sill or sill to support beam. That said, I'd double bolt ever 24 inches and add blocking/bridging even to other beams that are not sistered. Blocking transfers load to adjoining beams. 140 isn't that over the top as far as weight.

The bolts don't do much (they won't hurt).... They are not enough to actually laminate the two beams together in any significant way.

The blocking does not transfer weight so much as it prevents the joists from deforming laterally (twisting) under load.

In the OPs case, he did not indicate what the span between sills or sill and beam is.

The "sister" joist sections he placed are useless and add to the dead load (not that they are hurting anything).

OP: depending on span, you don't likely need to add any support. If you feel better adding it, then a single jack post is more than enough. Place a double 2x6 header over it with the jack in the center, spanning the 3 joists. The header should not "teeter" on top of the jack once snug. Two posts can be used if you span 5 joists.


If you tank is basically sitting on the center beam, then you really don't need to add anything.

 

[christwendt]

The bolts don't do much (they won't hurt).... They are not enough to actually laminate the two beams together in any significant way.

The blocking does not transfer weight so much as it prevents the joists from deforming laterally (twisting) under load.

In the OPs case, he did not indicate what the span between sills or sill and beam is.

The "sister" joist sections he placed are useless and add to the dead load (not that they are hurting anything).

OP: depending on span, you don't likely need to add any support. If you feel better adding it, then a single jack post is more than enough. Place a double 2x6 header over it with the jack in the center, spanning the 3 joists. The header should not "teeter" on top of the jack once snug. Two posts can be used if you span 5 joists.


If you tank is basically sitting on the center beam, then you really don't need to add anything.

Thanks for explaining all this. Interesting you mention that the bolts dont do much. I used construction adhesive, nails, and screws to sister the joists. So you mention the sister joist sections are useless. Do they become useful once I add a header and a jack? The tank is 3 inches off the center beam in house. I started to enforce because I would notice the tank wobble when our 80 lb Dog would jump around. I also noticed it if I jumped back and forth by the tank. It was not a big wobble but I could tell if I looked closely. Even after sistering, blocking, and using a floor jack with a header i still get a slight wobble. The tank is level which makes me think maybe its my sub floor flexing and I'm wondering If i'm over worrying. Thanks so much man!

 

[aws2266]

Thanks for explaining all this. Interesting you mention that the bolts dont do much. I used construction adhesive, nails, and screws to sister the joists. So you mention the sister joist sections are useless. Do they become useful once I add a header and a jack? The tank is 3 inches off the center beam in house. I started to enforce because I would notice the tank wobble when our 80 lb Dog would jump around. I also noticed it if I jumped back and forth by the tank. It was not a big wobble but I could tell if I looked closely. Even after sistering, blocking, and using a floor jack with a header i still get a slight wobble. The tank is level which makes me think maybe its my sub floor flexing and I'm wondering If i'm over worrying. Thanks so much man!

I'm setting up a 125g and reinforcing the floor. I'm gonna set up a 4x4 across the joists with a floor jack in the middle for support under the front side of the tank. It's probably overkill since the tank is sitting perpendicular on the joists and sits partly on a concrete wall. Peace of mind is worth the $100 I'll spend on it. That and my floor jacks(have two already down there for my 120g) don't sit in the middle of the basement, they are off to the side. Will make a couple closets where the floor jacks are.

Blocking helps with bounce. If you block the joists properly across a room, you should be able to jump in the middle of said room and not affect the tank much. Anyway, my 2 cents. Happy reefing buddy!

 

[christwendt]

I'm setting up a 125g and reinforcing the floor. I'm gonna set up a 4x4 across the joists with a floor jack in the middle for support under the front side of the tank. It's probably overkill since the tank is sitting perpendicular on the joists and sits partly on a concrete wall. Peace of mind is worth the $100 I'll spend on it. That and my floor jacks(have two already down there for my 120g) don't sit in the middle of the basement, they are off to the side. Will make a couple closets where the floor jacks are.

Blocking helps with bounce. If you block the joists properly across a room, you should be able to jump in the middle of said room and not affect the tank much. Anyway, my 2 cents. Happy reefing buddy!

Sounds very similar to what I’m doing. I hope to someday learn how to build a closest haha. I’m just getting tool handy. I can’t block properly because the entire ceiling is finished. So you think a very slight wobble if you jump by it is normal/okay?

 

[BeanAnimal]

All floors bounce/shake when walked on or jumped on. Being so close to a bearing beam or wall, there will be very little deflection.

The single post under the header would prevent significant deflection if the load bearing member was further away. Using a post under each end of it will prevent a bit of bounce where you have it set now. Given the proximity of the tank to the bearing, you are well supported to begin with for that size tank. I don’t know the dimension, but a 120 is roughly 1200 pounds. Call it 2’x6’ = 12 square feet. That is 100 psf. Your floor is likely designed to a 40 psf distributed load and ~300 psf concentrated load (or more as the joists can’t be undersized and Come in 2” height increments.)

So unless you have a weight set, refrigerator and gigantic in-laws and a keg next to the tank….

 

[aws2266]

Sounds very similar to what I’m doing. I hope to someday learn how to build a closest haha. I’m just getting tool handy. I can’t block properly because the entire ceiling is finished. So you think a very slight wobble if you jump by it is normal/okay?

Oh, don't get me wrong, I'm the furthest thing away from being handy. The closet will be built by someone else. lol Your tank is going to wobble a little regardless. It just depends on how much wobble you're comfortable with. Like I said, I'm not a handyman so don't quote me that.