How to add structural support under this joist?

[orioncyg]

Before you set the aquarium up, have a real good look at the floor joist or joists that will be bearing that weight. Make sure the ends are not rotted, make sure nobody has cut into them for whatever reason in the past. I do wonder why the floors are sagging to befin with, not trying to alarm you, everything could and probably is fine but have a real good look before adding 1400 pounds of weight, and don’t forget there will come a time when possibly 3 adults are standing at that aquarium looking at the fish, so don’t forget that weight as well. You should be able to find information about spans online

I had a structural engineer inspect the house a year ago during the contingency period and he didn't note any issues, though I honestly don't know how thorough the inspection was. He just said it's common (more that it's the norm rather than the exception) for old houses to not have level floors and it's usually due to initial settling from 100 years ago when the house was built or continued settling over the past 100 years.

I shined my phone's flash light and looked at the entire span of the joist a couple days ago and didn't see any issues.

 

[orioncyg]

I would do lolly columns. Send some of the weight down to the basement floor. That's hard to get at, but steel columns are thin at the top and make it a little easier.

Do you use the terms "lally columns" and "jack posts" interchangeably? If not, what's the benefit of a lally column vs jack post for this particular scenario>

 

[Burt Shaver]

I had a structural engineer inspect the house a year ago during the contingency period and he didn't note any issues, though I honestly don't know how thorough the inspection was. He just said it's common (more that it's the norm rather than the exception) for old houses to not have level floors and it's usually due to initial settling from 100 years ago when the house was built or continued settling over the past 100 years.

I shined my phone's flash light and looked at the entire span of the joist a couple days ago and didn't see any issues.

Your right, home inspections are a guarantee of nothing, I’ve seen floor joists sitting directly on the concrete frost wall before and of course concrete and wood touching doesn’t go well, so just thought I’d mention it. Do you have room in there to laminate another 2x10 to the existing one? Room to nail I mean? If you do have room, one option I can think of is to laminate using pl premium and steel ardox nails 2 vertically every 4 inches.

 

[orioncyg]

Your right, home inspections are a guarantee of nothing, I’ve seen floor joists sitting directly on the concrete frost wall before and of course concrete and wood touching doesn’t go well, so just thought I’d mention it. Do you have room in there to laminate another 2x10 to the existing one? Room to nail I mean? If you do have room, one option I can think of is to laminate using pl premium and steel ardox nails 2 vertically every 4 inches.

Hm you mean sistering right? If that nail is supposed to go through the thicknesses of both boards (i.e., 4" in thickness), then I don't think I have room. Those HVAC ducts make hammering impossible. Maybe I can do it with some kind of bracket fastener and have a screw nail into each board separately and they're joint together via the bracket?

 

[LB-1911]

Do you use the terms "lally columns" and "jack posts" interchangeably? If not, what's the benefit of a lally column vs jack post for this particular scenario>

"The terms jack post and lally column are often used interchangeably"
/\ Source @

Lally Column vs Jack Post: What’s the Difference?

weekendbuilds.com

 

[JSGAuto]

I think you should consider buying a smaller tank, moving it somewhere else, or hiring a professional.

Petsmart use to sell bow front tanks that looked cool, and were smaller.

This doesn't seem like its something you are comfortable doing. We are in the realm of engineered structure with this floor load, on an old house. This is 3-4x typical live load for new construction.

Jim (Engineer)

 

[orioncyg]

I'm going to wait for the jackpost to get here before deciding what to do. I ordered this one and it arrives on tuesday https://www.homedepot.com/p/VEVOR-H...st-Pole-DBZCQJD1G1121DU27V0/332851750#overlay

I do appear have a straight line directly down from the joist. Just confirmed with a level that I have. I don't know what the diameter of this post is. Looks like it's somewhere between 2-3" which I think will work. if it's larger than 3", then it's not going to be able to be centered on the joist.

 

[wssix99]

This isn't a big deal. Have a beer, fill the thing with water and don't worry about it.

If it was a big deal... they wouldn't see it at Petco. 1/2 ton isn't really that much. Its like 3 football lineman standing in your lifting room to have their picture taken. (If you had a dinner party with 3 Hall of Fame lineman, you wouldn't think twice about it or about reinforcing your floor - no need to overthink this.)

^ The lineman thing are also (more challenging) "live" loads. The aquarium is a "dead" load and easier for your floor to handle. You are close enough to your exterior walls that the bending stresses on the joist will be less, which is another reason not to sweat this - but you shouldn't sweat it in the first place.

 

[CraigStu]

I like the adjustable post idea the OP has ordered. But I wonder if he will be able to adjust it once it is in between all the obstacles. So then I got to thinking what about installing it so the adjustable end is at the floor. It would look unusual but is there any technical reason it shouldn't be done?

 

[cgrutt]

I like the adjustable post idea the OP has ordered. But I wonder if he will be able to adjust it once it is in between all the obstacles. So then I got to thinking what about installing it so the adjustable end is at the floor. It would look unusual but is there any technical reason it shouldn't be done?

You'll just pop the floor up if its not supporting the beam (floor joist, in this case). You want it on the beam (joist) to transfer weight distributed across the framing member to ground.

ETA probably good idea to put post on some sort of platform or pier to distribute weight on wider area of floor not knowing thickness or condition of slab.

 

[orioncyg]

I like the adjustable post idea the OP has ordered. But I wonder if he will be able to adjust it once it is in between all the obstacles. So then I got to thinking what about installing it so the adjustable end is at the floor. It would look unusual but is there any technical reason it shouldn't be done?

my plan is to have it pre-adjusted to be within 1" of what I need and get it in there.
it's actually arriving early and will be here today, so I should have answers soon

 

[orioncyg]

This isn't a big deal. Have a beer, fill the thing with water and don't worry about it.

If it was a big deal... they wouldn't see it at Petco. 1/2 ton isn't really that much. Its like 3 football lineman standing in your lifting room to have their picture taken. (If you had a dinner party with 3 Hall of Fame lineman, you wouldn't think twice about it or about reinforcing your floor - no need to overthink this.)

^ The lineman thing are also (more challenging) "live" loads. The aquarium is a "dead" load and easier for your floor to handle. You are close enough to your exterior walls that the bending stresses on the joist will be less, which is another reason not to sweat this - but you shouldn't sweat it in the first place.

but the 3 lineman aren't going to be standing there for years. i think the point is issues compound over time, caused by loads that exert consistent load over al ong period of time

 

[Burt Shaver]

but the 3 lineman aren't going to be standing there for years. i think the point is issues compound over time, caused by loads that exert consistent load over al ong period of time

Glad you didn’t take that comment to heart, correct me if I’m wrong but the tank will be sitting parallel on one joist correct? Not perpendicular so that it’s going across 3 joists. 1300 or 1400 pounds on one 2x10 plus the possibility of 2 or 3 people standing on that one joist at some time in the future, possible 2000 Ibs with 600 or that being live weight. I’m glad your doing some homework

 

[andyvh1959]

Your right, home inspections are a guarantee of nothing, I’ve seen floor joists sitting directly on the concrete frost wall before and of course concrete and wood touching doesn’t go well, so just thought I’d mention it. Do you have room in there to laminate another 2x10 to the existing one? Room to nail I mean? If you do have room, one option I can think of is to laminate using pl premium and steel ardox nails 2 vertically every 4 inches.

Not to be jacking this thread but, huh? Every house I've owned in Wisconsin and every basement I've been in where the floor joists are visible in the basement have the floor joists and sill joists sitting directly on the concrete wall, block wall or stone wall foundation. Some may have a thin barrier like a sill seal between the wood and concrete, or maybe the top of the foundation wall was coated with roofing asphalt before the joists were set on the foundation to build the deck. But I have never heard of any discussion of wood floor joints on the foundation wall being an issue. Am I missing something here?

I have seen the results of inadequate flashing or poor structural design that does not protect the floor/sill joists from moisture damage over time/decades.

 

[orioncyg]

so i was able to get the post in there. that smaller diameter adjustable piece towards the top plate really saved me. otherwise, I wouldn't have been able to clear that duct right behind the post (the one to the right of the joist I'm supporting in the side view picture).

I haven't fastened it yet. I think getting the top fastened will be another challenge. I have about 1/2-3/4" of space to work with above the top plate which is not thick enough for a wood block.

where it's sitting right now is approximately the middle of the length of the aquarium, maybe slightly to the left about 6" or so. i would have a lot more room if I moved it to the left by another foot (i can move the electrical junction box elsewhere), but then the support would be 1.5" from the left side of the aquarium and 4.5" from right.

 

[cgrutt]

Would it be possible to drop that duct temporarily, even if you had to cut it with multitool and reassemble, and sister another 2x10 (?) against joist. Use construction adhesive and structural screws to attach new joist to old and fasten the top plate to both joists? If you can get the new joist full span where its supported at ends it would obviously be best. You may have to get creative to reattach duct if you have to cut it but you probably can drop it without cutting with some effort.

Again, I'd think about putting that post on some sort of base to distribute weight on floor not knowing thickness or condition of slab.

If none of that is possible what you have seems better than nothing but it would be ideal to get another joist up there.

 

[Bunsen Honeydew]

Get a concrete paver block to put under the base of your column, adjust the height of the column to the distance between the paver and the joist. Most pavers are 1.75 - 2" thick. You can adjust the height further with hardwood wedges between the paver and column base if you need to.
Main thing is make sure the column is plumb.
Edit: You can probably turn the lower part of the column to get the top screw adjuster snug against the joist. It doesn't look like the top plate is free to turn much.

 

[mikedodge]

That looks like it'll do the job. You might want to stick a patio stone or something similar under it to spread the weight a little bit. If you're really worried ad a second post to double up on it.

 

[billconner]

I think this will be fine. If you needed more room at top, you could screw (timber lok) a 2 or 3 foot 2x4 to joist. It would just give a little more room.

 

[Burt Shaver]

Not to be jacking this thread but, huh? Every house I've owned in Wisconsin and every basement I've been in where the floor joists are visible in the basement have the floor joists and sill joists sitting directly on the concrete wall, block wall or stone wall foundation. Some may have a thin barrier like a sill seal between the wood and concrete, or maybe the top of the foundation wall was coated with roofing asphalt before the joists were set on the foundation to build the deck. But I have never heard of any discussion of wood floor joints on the foundation wall being an issue. Am I missing something here?

I have seen the results of inadequate flashing or poor structural design that does not protect the floor/sill joists from moisture damage over time/decades.

Your not missing anything, I used to run a disaster restoration business so I’ve been in a ton of homes, you got it right, I’ve seen them without sill gasket especially from homes built in the 50’s, 60’s. Seemed to be a lot of guys that built there own homes in that time period

 

[billconner]

Your not missing anything, I used to run a disaster restoration business so I’ve been in a ton of homes, you got it right, I’ve seen them without sill gasket especially from homes built in the 50’s, 60’s. Seemed to be a lot of guys that built there own homes in that time period

How many you r seen show significant decay or other detrimental effects? I've lived in two 100+ year old houses - wood on masonry (limestone both) and no decay what so ever.

 

[Burt Shaver]

How many you r seen show significant decay or other detrimental effects? I've lived in two 100+ year old houses - wood on masonry (limestone both) and no decay what so ever.

I would say two. Are you ok with me telling the OP to check the ends of the joists? Yea, I live in a stone home built in 1840, original logs for floor joist still good

 

[orioncyg]

Would it be possible to drop that duct temporarily, even if you had to cut it with multitool and reassemble, and sister another 2x10 (?) against joist. Use construction adhesive and structural screws to attach new joist to old and fasten the top plate to both joists? If you can get the new joist full span where its supported at ends it would obviously be best. You may have to get creative to reattach duct if you have to cut it but you probably can drop it without cutting with some effort.

Again, I'd think about putting that post on some sort of base to distribute weight on floor not knowing thickness or condition of slab.

If none of that is possible what you have seems better than nothing but it would be ideal to get another joist up there.

I'm sure it's possible. I just wouldn't feel comfortable DIY'ing that.

i can definitely put a larger base on the ground for sure.

I actually wonder if I'm good w/o fastening the top or bottom and rely solely on the compressive forces to keep the jack post in place

 

[orioncyg]

Get a concrete paver block to put under the base of your column, adjust the height of the column to the distance between the paver and the joist. Most pavers are 1.75 - 2" thick. You can adjust the height further with hardwood wedges between the paver and column base if you need to.
Main thing is make sure the column is plumb.
Edit: You can probably turn the lower part of the column to get the top screw adjuster snug against the joist. It doesn't look like the top plate is free to turn much.

Yeah I'm planning on getting a larger surface area for the bottom. Will look into a concrete paver block.
I don't understand what you mean by "distance between paver and joist." wouldn't the height of the column be adjusted by the thickness of the paver?

i think the plumbness of the column is a function of only 2 things:
1) how level the ground** is?
2) how flush the bottom surface of the column is with the ground**?

** ground here means the concrete slab or the paver if I add the paver

and lastly, yeah there's not much space for the top place to rotate or translate. the HVAC ducts on both sides are in the way

 

[orioncyg]

I think this will be fine. If you needed more room at top, you could screw (timber lok) a 2 or 3 foot 2x4 to joist. It would just give a little more room.

do you mean sister or screwing in from under the joist?

 

[orioncyg]

can't remember if I mentioned this, but I think I discovered another joist buried right next to the foundation wall. it's bit hard to see. i can't quite make out what's happening with it because it kind of looks like it just disappears mid-span...that joist is probably right under my living room wall so it's not going to be directly under the footprint of the aquarium

 

[cgrutt]

I'm sure it's possibly. I just wouldn't feel comfortable DIY'ing that.

i can definitely put a larger base on the ground for sure.

I actually wonder if I'm good w/o fastening the top or bottom and rely solely on the compressive forces to keep the jack post in place

Don't really know. Probably. The thing i worry about with the post being somewhat off center (relative to width of joist) is the single joist rolling. Thats primary reason why I think sistering another joist would be far better (in addition to carrying more load). I'd try to at least run a lag bolt on top plate to hold post in position. I "think" it would be best to secure post to floor but may not be needed with compressive load. Keep in mind I'm by no means a pro with this just my opinion.

 

[orioncyg]

Don't really know. Probably. The thing i worry about with the post being somewhat off center (relative to width of joist) is the single joist rolling. Thats primary reason why I think sistering another joist would be far better (in addition to carrying more load). I'd try to at least run a lag bolt on top plate to hold post in position. I "think" it would be best to secure post to floor but may not be needed with compressive load. Keep in mind I'm by no means a pro with this just my opinion.

So I think one major reason for fastening to the bottom is if something were to knock the post out of the way, e.g., someone trips and falls into the post -- unlikely to happen in that area however
I might fasten it just for peace of mind. just an additional step and I'll probably have to get specialized tools to drill into the ground or a paver if I'm going that route

 

[cgrutt]

So I think one major reason for fastening to the bottom is if something were to knock the post out of wall, e.g., someone trips and falls into the post -- unlikely to happen in that area however
I might fasten it just for peace of mind. just an additional step and I'll probably have to get specialized tools to drill into the ground or a paver if I'm going that route

Good polyurethane based construction adhesive might help hold it in place and/or two-part structural epoxy (comes in a single tube and mixes with included tip) for paver to concrete and post to paver connection (put lag in top if you go this route). If you have a hammer drill a tap con connector is fairly easy and would be a better mechanical anchor though. Just want to hold it in place.

 

[orioncyg]

Good polyurethane based construction adhesive might help hold it in place and/or two-part structural epoxy (comes in a single tube and mixes with included tip) for paver to concrete and post to paver connection (put lag in top if you go this route). If you have a hammer drill a tap con connector is fairly easy and would be a better mechanical anchor though. Just want to hold it in place.

sorry I'm full of typos today. just corrected my previous comment.
I'll look into fastening it in January -- I'm actually about to head out for vacation this thursday for a little over 3 weeks. I won't fill the tank with water until I get back and have all this setup.

 

[cgrutt]

Just a note about post... keep in mind you are potentially transferring a portion of the floor load and whatever else is coming through floor (portion of weight from 2nd floor, roof etc) plus portion of weight of aquarium to your slab with addition of post. Without knowing condition or thickness of slab and the fact that there probably is no footer directly below post there is some risk (probably negligible but unknown) of slab cracking, esp if pour was thin or if there are any voids. You can kinda gauge this by lightly tapping floor with a hammer or other solid object and listen for changes in tone. If it sounds hollow there are likely voids below slab. Thats why I recommended adding some base to spread load. Just wanted to mention so you can consider potential issues. As stated by others best to have a pro (architect/engineer/or even competent contractor) look at what you're planning to do and assess condition of home, esp given age and fact that floors are already sagging. My $0.02, good luck!

 

[billconner]

do you mean sister or screwing in from under the joist?

Screwing in from bottom - a deeper two-by. Just to get more room at top of Jack post.

 

[mike93lx]

I'm sure it's possible. I just wouldn't feel comfortable DIY'ing that.

i can definitely put a larger base on the ground for sure.

I actually wonder if I'm good w/o fastening the top or bottom and rely solely on the compressive forces to keep the jack post in place

I would absolutely secure it with at least a screw at the top. Its very unlikely to ever have a chance to fall over on someone, but it would at least eliminate the chances

 

[orioncyg]

Just a note about post... keep in mind you are potentially transferring a portion of the floor load and whatever else is coming through floor (portion of weight from 2nd floor, roof etc) plus portion of weight of aquarium to your slab with addition of post. Without knowing condition or thickness of slab and the fact that there probably is no footer directly below post there is some risk (probably negligible but unknown) of slab cracking, esp if pour was thin or if there are any voids. You can kinda gauge this by lightly tapping floor with a hammer or other solid object and listen for changes in tone. If it sounds hollow there are likely voids below slab. Thats why I recommended adding some base to spread load. Just wanted to mention so you can consider potential issues. As stated by others best to have a pro (architect/engineer/or even competent contractor) look at what you're planning to do and assess condition of home, esp given age and fact that floors are already sagging. My $0.02, good luck!

Maybe a dumb question but given my foundation is cinderblock and then parged with concrete (all the walls you see in the pics and videos I attached are parged concrete), could the ground be built similarly? i.e., could the actual foundation be cinderblock and the concrete slab we see is just built on top of it?

 

[orioncyg]

Screwing in from bottom - a deeper two-by. Just to get more room at top of Jack post.

Hmm this could possibly work. The layers would then look something like (from top down):
joist -> new 2x4 (or whatever) block -> jack post top support
i think the additional layer, while helpful with spacing issues, could just introduce another point for failure.

 

[cgrutt]

Maybe a dumb question but given my foundation is cinderblock and then parged with concrete (all the walls you see in the pics and videos I attached are parged concrete), could the ground be built similarly? i.e., could the actual foundation be cinderblock and the concrete slab we see is just built on top of it?

If you're asking if there is cinderblock ("CMU" nowadays) under your slab I've never seen that and highly doubt it. Obviously no way to know, esp over Internet, but I suspect its highly unlikely.

 

[cgrutt]

Hmm this could possibly work. The layers would then look something like (from top down):
joist -> new 2x4 (or whatever) block -> jack post top support
i think the additional layer, while helpful with spacing issues, could just introduce another point for failure.

I believe @billconner is suggesting what I did earlier, attach a 2x4 to bottom of joist. I would run it as long as possible to help distribute weight and stiffen the joist. Sistering a new joist would be better but I believe there is more benefit to be gained by adding a 2x4 (secured appropriately with perhaps construction adhesive and screws as stated earlier) then cause for concern.

 

[mikedodge]

They wouldn't pour the floor over cinder block.

You should be OK you don't have the full load on that post other then a paver or something to help distribute the weight.

 

[mikedodge]

I believe @billconner is suggesting what I did earlier, attach a 2x4 to bottom of joist. I would run it as long as possible to help distribute weight and stiffen the joist. Sistering a new joist would be better but I believe there is more benefit to be gained by adding a 2x4 (secured appropriately with perhaps construction adhesive and screws as stated earlier) then cause for concern.

There's no need for that unless it looks like the post is starting to dig into the bottom of the joist. The 2x4 wouldn't add any strength.

 

[cgrutt]

There's no need for that unless it looks like the post is starting to dig into the bottom of the joist. The 2x4 wouldn't add any strength.

I happen to disagree but great thing about Internet its all free advice and everybody is entitled to their opinion. Here's a illustration of what I'm referring to.