Floor loading... is it strong enough?

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DesertRider

Active Member
Joined
Mar 4, 2021
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Location
Boulder City Nevada
Thanks for allowing me to join the group, I recently retired after 50 years, from the Military both Active duty, and Contractor status

We purchased a house in Southern Nevada, That came with a detached 12x20 “storage building”... built on 9 each, 12 inch diameter concrete piers. The outside frame is double 2X8 Douglas Fir with another double 2X8 running down the middle lengthwise. The joist are of 6 foot, 2x6’s on 16 inch centers, off each side of this center support, and the floor is a single layer of bare, 3/4 inch T&G plywood.

My question is... is this construction suitable to support my Workshop consisting among other general items, a 9x21 lathe, Vertical Mill, SawStop Table Saw, Jet Bandsaw, four each, med. size tool boxes and assorted work bench and storage shelves.

Would a second layer of 3/4 T&G, be necessary? And I really don’t like the idea of bare ply as the floor, what would be a suitable material to cover it with?

Thank you, Appreciate any, and all advice, Good, Bad and Neutral...

Chuck
KB7CG
 
First off welcome to the forum Chuck.



That sounds like a lot of equipment in that size of space, but not sure what lathe and mill you have.



I personally like the idea of a hardwood T&G flooring running 90 to the joists. They wouldn’t need much in the way of finishing in a shop area and will take wear much better than plywood and will help spread out loads. If your equipment is heavy in spots you could always add steel plates at the point loading.



I also have a smaller workshop but not as much equipment (wish I did) as you and I’m always fighting with longer work running into things. I drag stuff in and out to the garage area to work on if it is large.



Welcome and post some pics if you can.

Congrats on retirement I have been loving every day of mine.
 
Standard building codes address both commercial and residential floor loading, in two manners, live load and dead load.

Residential is 40psf live,(pounds per sq.ft.), in non sleeping room areas, 30 for sleeping. The dead load is 20psf.
Commercial is 50psf live.

Here is a link that you can use to calc. your's;https://www.hunker.com/13400811/how-to-calculate-floor-load-capacity
 
I recall that in my area, load bearing capacity of the ground is typically between 1000 psf and 5000 psf if it is undisturbed soil. You can possibly search online for better idea of what is common in your area. But if we say 2000 psf, your footings would be good for 14,000 pounds, and the shed, lets call it 3000 pounds for the structure. I'm not sure what kind of factor of safety you are supposed to have, but that leaves 11,000 pounds for you and equipment.

The lathe does not sound too big. Table saw, bandsaw etc I doubt are issues. Probably another layer of plywood floor would be a good idea. Possibly you would want to put the mill directly over a footing. However, if the mill is a bridgeport type, I can see that possibly being too heavy to be supported by one footing. Any idea what it weighs ?
 
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Thanks everyone for your welcome reply's and suggests... I tried the above link to calculate loading, but couldn’t get it to work (I’ll play around with it later, or just google “How to Calculate...”) the mill is not a Bridgeport, just a small to midsize Chinese knock-off, maybe 700 lbs max and same for the lathe... the tools and accessories I have for each, probably weight more than the machines themselves.

I’m well aware of building codes and their requirements, but I’m not sure if who ever built this Storage shed followed any “codes”... in this area a permit is not required for this size “outbuilding” although it does appear to be very well built... I think what I’ll do is double the floor boards under the two heavyweights.

I was thinking about dust as well as normal wear & tear on the plywood floor itself... I believe before I move anything in the building, I’ll tile first with a thick(?) Vinyl that I can replace if damaged unless someone has a better idea... at this stage I’m open to any suggestions...

Also Bud16415, thanks on the retirement congrats... I should have done it back in 2013 when I first became eligible... when you have a job you love, and are good at it, and appreciated... it’s hard to walk away from...
 
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