floor strength

hello letterpress friends! i have a small shop in chicago.

currently i’m on the 3rd floor of an industrial building with a freight elevator (6000# max). the floors are wood & i have a plywood subfloor in my space on top of the original floor.

i recently put a down payment on a 10x15 c+p craftsman automatic & am considering purchasing another 10x15 c+p hand fed (i have one already).

my questions is how do i know if my floor is substantial enough to hold all that weight?
is there a formula?
i have a triumph paper cutter (550lbs.), a couple marble top tables, a type cabinet filled with type & lots of shelving with paper.
the signs in the hallway say 100# max. but all other type is faded & i can’t read what else it says. is that square foot? my space is 700 sq. ft.

basically can the floor hold 3 presses, paper & shelving, a cutter, type cabinet & me & my intern?

i have no idea what my neighbors have for large equipment but i know its industrial, one is a sculptor with lots of welding & grinding. the other is a wood shop.

any suggestions, concerns or other info is appreciated!


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Check and see what type of joists are under your floor. If they are 2x8 or 2x10 on 16” centers you should be OK. If in doubt, place the presses on 2 layers of 3/4” plywood screwed together that are just about 6” bigger than the footprint of the press. This should distribute the weight without you having to worry.
Of course if the floor is not in good shape, you’ll know where your presses are - in the basement!
All kidding aside, you should be OK.

Yes there are formulas. Floor system loading is determined by joist size, on center spacing, and most importantly, the span or length between bearing supports. It is measured in pounds per square feet of live and dead load. Live load is the load that is not permanent like people. Dead load is everything else. If your building was in fact designed with Industrial loading, it will have a code required design load of 250lbs per square foot and would be quite adequate if still in good condition. If solid timber, it would likely be something much larger than 2x10. If of newer construction it would most likely be trusses. If it may have actually been an office building or some other end use, it may be designed for something much less. I think the likelyhood given your information about other tenants is that the building was designed for high designs loads. Of more concern is that this equipment puts concentrated loads on the floor. Anything you can do like runners or plywood under the weight help. The idea is to not ask one or two joists/trusses to do all the support work. If you can determine which direction the joist run, position the press and runners to go over as many of them as possible. Wood floor systems would also benefit if you placed most of the heavy stuff near bearing walls, rather than all out in the middle of the floor/span. Wood floor systems are also rather forgiving when over loaded, but, If you still worry, cannot find out from other tenants, signs, or the building owner, a structural engineer can quickly determine if there are any issues of concern.

thank you both for all the information. this is very helpful.
the joists are rather large & as you can see my handfed press is along the outer wall. the new automatic press will most likely be next to it for ease of wiring.
thanks again! i really appreciate your knowledge & help.

image: studio.jpg


I would check the direction of the joists, they should run the same way as the floor above and for safety skip a joist. If you run the machines side by side you are loading up the joist in the middle. If possible get access to the space below and check the condition (dry rot, termites or holes drilled for plumbing or wiring) if the ceiling is open like your space. We had a tenant upstairs load so many books along a wall the joists deflected 3 inches. In our building the outer floor is rated at 125 pounds a foot (wood-1920’s) and the inner floor at 250 (concrete-1948). It depends when it was built and what the codes were at the time and the original use. I have opened up ceiling to find the plumbers 80 years ago had hacked a row of joists to run a vent. Please take this seriously. Good luck and happy printing! I would die to have a window!