Do I need to enforce my floor?

Dcloser12 · Jan 3, 2022

Floors are designed to support 50-60psf. It comes down to dimensions. 72x20 for a 100 gallon is about 880lbs the footprint means it's 12sq ft. 880÷12=73psf. That's a no go. The solution is a simple one. Make a bigger footprint. Like wise 3x6 is 18.. 880÷18=48psf which.. well is acceptable. Maybe not in the middle of a room. It would become a trampoline. But against a bearing wall? Easily. If the outside floor joist is pinned to the wall framing then you have limited deflection and the joist beside it is picking up 1/3rd of the load but all the deflection. The tank would bounce more but you get about 70psf you wanna make it work you need to know your joist span and joist width. The wider a joist and the closer both bearing points are it rest on the hight the psf rating. Joist construction also plays a role. It's easier to laminate 2 or 3 joist together to essentially increase the psf to 120-150 than it is to add beams in a basement or crawl space. This becomes a better idea when dealing with false ceilings. The advice I can give is either increase the base footprint or sister in 2 more joists. Both accomplish the same goal

Brian_68 · Jan 3, 2022

Dcloser12 said:
Floors are designed to support 50-60psf. It comes down to dimensions. 72x20 for a 100 gallon is about 880lbs the footprint means it's 12sq ft. 880÷12=73psf. That's a no go. The solution is a simple one. Make a bigger footprint. Like wise 3x6 is 18.. 880÷18=48psf which.. well is acceptable. Maybe not in the middle of a room. It would become a trampoline. But against a bearing wall? Easily. If the outside floor joist is pinned to the wall framing then you have limited deflection and the joist beside it is picking up 1/3rd of the load but all the deflection. The tank would bounce more but you get about 70psf you wanna make it work you need to know your joist span and joist width. The wider a joist and the closer both bearing points are it rest on the hight the psf rating. Joist construction also plays a role. It's easier to laminate 2 or 3 joist together to essentially increase the psf to 120-150 than it is to add beams in a basement or crawl space. This becomes a better idea when dealing with false ceilings. The advice I can give is either increase the base footprint or sister in 2 more joists. Both accomplish the same goal

Just to add a 100 gallon tank is way over 880 lbs once you add rock, lights, stand, sump plus water and the tank itself.

ZoWhat · Jan 3, 2022

Dcloser12 said:
Floors are designed to support 50-60psf.

So with me weighing 210lbs, if I stand within one square foot in my upstairs bedroom... I fall thru the floor all the way into the basement

Interesting.....

outhouse · Jan 3, 2022

my 210 has sunk the floor over a 1/4 on one side. It was next to a joice and support beams, but the house is over 130 years old. I will get under there one of these days and jack it up and use shakes to fill gaps

Dcloser12 · Jan 3, 2022

zoa what said:
So with me weighing 210lbs, if I stand within one square foot in my upstairs bedroom... I fall thru the floor all the way into the basement

Interesting.....

That's not how it works. That's the total load rating for the entire floor. So 10x10x 40 or 50 you are looking at 4-5k. If you take that entire floor rating and add it to one joist yes, you will find a new home on the floor below you. Like wise if you do the math That's about 6-700 lbs per joist the floor is designed to hold. MAX that is over the span of the entire joist. So yes if you weigh 600lbs your going through. If you add a 1400lb tank to one or 2 joist.. YES it's going through.

Brian_68 · Jan 3, 2022

Dcloser12 said:
That's not how it works. That's the total load rating for the entire floor. So 10x10x 40 or 50 you are looking at 4-5k. If you take that entire floor rating and add it to one joist yes, you will find a new home on the floor below you. Like wise if you do the math That's about 6-700 lbs per joist the floor is designed to hold. MAX that is over the span of the entire joist. So yes if you weigh 600lbs your going through. If you add a 1400lb tank to one or 2 joist.. YES it's going through.

You are technically not going to fall thru, this rating is based on joist deflection, not to failure.

Dcloser12 · Jan 3, 2022

Brian_68 said:
You are technically not going to fall thru, this rating is based on joist deflection, not to failure.

Put that kind of weight on a joist or 2 and then add a live load that causes harmonic shaking or bouncing. 1400lbs when the floor is trying to bounce up or down at 2mph means a 2800lb vibration or worse depending on how many people are in there. The forces are truly mind blowing. I'm just saying the answer is no. It's not going to work. You need to sister a few rafters or add a bearing point.

tanked4u · Jan 3, 2022

+1 vote to follow the advice of the structural engineer

The catastrophe of having a tank crash through the floor would be absolutely epic. Don't risk it, or if you do, take lots of pictures if it fails. It would be a sight to see.

Good luck.

christwendt · Jan 3, 2022

tanked4u said:
+1 vote to follow the advice of the structural engineer

The catastrophe of having a tank crash through the floor would be absolutely epic. Don't risk it, or if you do, take lots of pictures if it fails. It would be a sight to see.

Good luck.

What should I expect to pay for that kind of service ?

christwendt · Jan 3, 2022

Dcloser12 said:
Floors are designed to support 50-60psf. It comes down to dimensions. 72x20 for a 100 gallon is about 880lbs the footprint means it's 12sq ft. 880÷12=73psf. That's a no go. The solution is a simple one. Make a bigger footprint. Like wise 3x6 is 18.. 880÷18=48psf which.. well is acceptable. Maybe not in the middle of a room. It would become a trampoline. But against a bearing wall? Easily. If the outside floor joist is pinned to the wall framing then you have limited deflection and the joist beside it is picking up 1/3rd of the load but all the deflection. The tank would bounce more but you get about 70psf you wanna make it work you need to know your joist span and joist width. The wider a joist and the closer both bearing points are it rest on the hight the psf rating. Joist construction also plays a role. It's easier to laminate 2 or 3 joist together to essentially increase the psf to 120-150 than it is to add beams in a basement or crawl space. This becomes a better idea when dealing with false ceilings. The advice I can give is either increase the base footprint or sister in 2 more joists. Both accomplish the same goal

This is way over my head to be honest. What should I expect to pay an engineer to look and do the job ?

JNalley · Jan 3, 2022

christwendt said:
What should I expect to pay for that kind of service ?

This depends on so many factors... Structural Engineers in Central Florida would be cheaper than one for NYC or Los Angeles for instance. Use contractors.com or some other service like that and look at ratings and read reviews is really the only way to get input on the persons quality and integrity. So...

edit: also try homeadvisor or angi (formerly Angie's List) and there are a few others out there... Good luck!

christwendt · Jan 3, 2022

Dcloser12 said:
That's not how it works. That's the total load rating for the entire floor. So 10x10x 40 or 50 you are looking at 4-5k. If you take that entire floor rating and add it to one joist yes, you will find a new home on the floor below you. Like wise if you do the math That's about 6-700 lbs per joist the floor is designed to hold. MAX that is over the span of the entire joist. So yes if you weigh 600lbs your going through. If you add a 1400lb tank to one or 2 joist.. YES it's going through.

The tank would only be on like 2 joist since it’s running parallel to the joist.. is it possible to do it parallel to the joist or just it be perpendicular?

tanked4u · Jan 3, 2022

christwendt said:
What should I expect to pay for that kind of service ?

I have no idea how accurate it is, but here is something.....

Structural Engineer Cost Estimate based on your ZIP code:

Learn how much it costs to Hire a Structural Engineer.

HomeAdvisor's Structural Engineer Cost Guide gives average prices to hire a professional engineer. Find prices for a structural inspection and report.

www.homeadvisor.com

Dcloser12 · Jan 3, 2022

I do own a construction company how ever my state codes are not the same as others. Our prices are not the same as others. Honestly if it were here I could walk in, take down the ceiling grid where I needed to work, install a few sisters and pop the ceiling back up for less than 1000$ if it was a commercial or agricultural zoned property its 3200 because of the fees, paperwork and prints. The job is not extensive but the actual information we are basing all this on is "tank is x gallons" no one here has any information to make a logical decision. I need room dimensions, joist size and spacing, joist composition (syp, i-joist, lam, syp2, etc) and then and only then could I or anyone else make an educated decision on what's the proper course of action. What I can tell you is NO IT WILL NOT WORK on one or 2 joist in parallel. Its to much dead load in a small spot. Floors are designed to spread the load over a broad area. You are literally putting it all in one spot.

christwendt · Jan 5, 2022

tanked4u said:
I have no idea how accurate it is, but here is something.....

Structural Engineer Cost Estimate based on your ZIP code:

Learn how much it costs to Hire a Structural Engineer.

HomeAdvisor's Structural Engineer Cost Guide gives average prices to hire a professional engineer. Find prices for a structural inspection and report.

www.homeadvisor.com

Dcloser12 said:
I do own a construction company how ever my state codes are not the same as others. Our prices are not the same as others. Honestly if it were here I could walk in, take down the ceiling grid where I needed to work, install a few sisters and pop the ceiling back up for less than 1000$ if it was a commercial or agricultural zoned property its 3200 because of the fees, paperwork and prints. The job is not extensive but the actual information we are basing all this on is "tank is x gallons" no one here has any information to make a logical decision. I need room dimensions, joist size and spacing, joist composition (syp, i-joist, lam, syp2, etc) and then and only then could I or anyone else make an educated decision on what's the proper course of action. What I can tell you is NO IT WILL NOT WORK on one or 2 joist in parallel. Its to much dead load in a small spot. Floors are designed to spread the load over a broad area. You are literally putting it all in one spot.

Sorry I got really busy. I have taken some measurements of the joists it’s 2x7. I however don’t know how long they are as I can’t see up into the ceiling into another room. I don’t know if it spans from front to back as one joist. I think there is a header in between the two rooms but the front to back is 22 feet. I have gotten quotes from structural engineers and the minimum is 450$. Then I will I need to pay to have the work done by a contractor. Maybe that is the best way to go as this is far over my head. I appreciate your time.