Will I end up with a hole in my floor? ......
- Thread starter marc88
- Start date
Hello; To Dan F. The article explains how the 40 pounds per square foot is factored into the load limits of a floor. A two hundred pound man can stand on one square foot and not crash a floor with a 40 pound per square foot limit. It is a combination of the total weight on a floor in static and dynamic loading. I also seem to recall that concentrated loads in a small area afect the load capacity of a floor. A 40 pound per square foot load capacity in an estimate of how much weight can safely be carried by a floor if the weight is spread evenly over the entire floor. A weak analogy may be an inch of rain. An inch of rain on the street spread out over a large area will not cover your shoes. That same inch of rain funneled into a ditch, creek or stream can cause severe local flooding.
A ten gallon tank is roughly 90 pounds. If it's footprint is 1 sq-ft, then in a room that is ten feet by ten feet (100 sq ft) that is 9000 pounds. The 40 pd /sq -ft safe load will only allow around 4000 pounds of safe load.
Here are some other site addresses I have found on the subject, but they are not as easy of a read as the one I posted before.
http://www.ehow.com/how_7485788_calculate-floor-load-capacity.html
The web address above is a site about calculating loadcapacities of floor joists. They use a formula for the strength of a beam: maximum load in pounds = FBd^2 / 9L.
The width of the woodjoist in inches is B (1.5 inches forstandard 2 by dimensional lumber.)
The depth in inches is d (7.25 in for a standard 2x8.)(9.25 in for a2x10)
The distance (span) in feet is L (Unsupported distance)
F is somethingcalled the fiber stress when wood bends. It varies with the type of wood butgraded lumber will be at least a 1,000 number, some are higher.
They use an example of 2x10 floor joists with a span of 14feet on 16 inch centers and come up with 1,019 pd for each joist. They figure the area supported by each joistas 18.7 sq ft. They get 54.5 pd per square foot of floor area. I think this includes the weight of theflooring and anything else that is supported by the joists. I looked at someother sites (Addresses listed below) and found a discussion of static loads andlive loads. Two sites describe how to measure the deflection of flooring due toweight loads.
http://www.johnbridge.com/vbulletin/deflecto.pl
http://www.awc.org/calculators/span/calc/timbercalcstyle.asp?species=Douglas+Fir-South&size=2x8&grade=Select+Structural&member=Floor+Joists&deflectionlimit=L%2F480&spacing=16&wet=No&incised=No&liveload=80&snowload=-1&deadload=10&submit=Calculate+Maximum+Horizontal+Span
I found these sites interesting but hard to pin down for ageneral rule of thumb. Too many variables involved; Type of wood, condition ofwood, dimensional lumber or engineered truss, age of wood and on and on.
http://www.eng-tips.com/viewthread.cfm?qid=62845&page=10
A ten gallon tank is roughly 90 pounds. If it's footprint is 1 sq-ft, then in a room that is ten feet by ten feet (100 sq ft) that is 9000 pounds. The 40 pd /sq -ft safe load will only allow around 4000 pounds of safe load.
Here are some other site addresses I have found on the subject, but they are not as easy of a read as the one I posted before.
http://www.ehow.com/how_7485788_calculate-floor-load-capacity.html
The web address above is a site about calculating loadcapacities of floor joists. They use a formula for the strength of a beam: maximum load in pounds = FBd^2 / 9L.
The width of the woodjoist in inches is B (1.5 inches forstandard 2 by dimensional lumber.)
The depth in inches is d (7.25 in for a standard 2x8.)(9.25 in for a2x10)
The distance (span) in feet is L (Unsupported distance)
F is somethingcalled the fiber stress when wood bends. It varies with the type of wood butgraded lumber will be at least a 1,000 number, some are higher.
They use an example of 2x10 floor joists with a span of 14feet on 16 inch centers and come up with 1,019 pd for each joist. They figure the area supported by each joistas 18.7 sq ft. They get 54.5 pd per square foot of floor area. I think this includes the weight of theflooring and anything else that is supported by the joists. I looked at someother sites (Addresses listed below) and found a discussion of static loads andlive loads. Two sites describe how to measure the deflection of flooring due toweight loads.
http://www.johnbridge.com/vbulletin/deflecto.pl
http://www.awc.org/calculators/span/calc/timbercalcstyle.asp?species=Douglas+Fir-South&size=2x8&grade=Select+Structural&member=Floor+Joists&deflectionlimit=L%2F480&spacing=16&wet=No&incised=No&liveload=80&snowload=-1&deadload=10&submit=Calculate+Maximum+Horizontal+Span
I found these sites interesting but hard to pin down for ageneral rule of thumb. Too many variables involved; Type of wood, condition ofwood, dimensional lumber or engineered truss, age of wood and on and on.
http://www.eng-tips.com/viewthread.cfm?qid=62845&page=10
I did read the article and I understand what you're saying, it's just in the first post It came across (to me, at least) as you were simply saying no more than 40#/square foot. Sorry for the confusion.
By the way, I am still waiting on the edge of my seat to see the hole in the floor where someone's tank fell through!
^ me too. I have seen tons of these threads and never heard of one single story of a tank crashing thru the floor. I am not saying its not possible but Ive yet to see it.
Hello; There was a thread in the past where damage due to weight was discussed and examples of damage caused by heavy tanks was cited. The damage is not likely to be a sudden dramatic failure such as crashing thru the floor. It will likely be a steady deformation of the support structures over time and apparently this has happened.
So catastrophic failure is highly unlikely, but damage over time is more realistic. 6 of one, half dozen of the other really, either way you end up with a messed up house which is what I'd like to avoid 
. I'll be working on floor reinforcement to prep for the tank soon, hoping to start the project sometime after Labor day. I'll probably put up a build thread once its underway. thanks for all the input.
. I'll be working on floor reinforcement to prep for the tank soon, hoping to start the project sometime after Labor day. I'll probably put up a build thread once its underway. thanks for all the input.Hello Marc88; Best of luck with the tank. When I moved into a house last year some of the floor joists had been compromised by a previous owner. There are limits to the size of holes that can be made in supporting structure and restrictions about where the holes and cuts can be placed. I spent considerable time and effort correcting some of the joists in my floor by sistering new joists to the old. This was in an area where I do not plan to place tanks. I plan to use a different room as a fish room. (One of the pluses of being single.) As I add more tanks and weight , I will very likely add some sort of srtructrual support. Having done the sistering, I may go with that ,plus lots of cross bracing, again in order to not lose open space in the basement. I have about a 2/3 basement and 1/3 crawl space. If using a room over the crawl space I will likely go with verticle 4x4 posts on small footers with horozontal 4x4's running at 90 degrees to the joists. Probably just as hard to do. I will look for your build thread in the future.
