Workshop flooring. How much weight can it support.

[MarkE]

I am getting a new 20" planer and wondering if I need to beef up the flooring in my shop. My current 15" planer is ~655 pounds, the new machine will be ~875 pounds. The 20" planer will be on a mobile base.

My shop is on a crawl space with 3/4" Advantech flooring on 2x10 joists, 16 oc. There is a main beam down the center of the building made from three 2x10 with another board (2x6?) on top. The center beam sits on two piers and the outside walls. The beam span is ~26 feet, the joists are ~11 feet from the beam to the outside walls. The planer will be approximately centered over the main beam about 3 feet from the outside wall.

So the question is, do I need to add more support to that section of the floor? And if so, what is the best way to do that?

 

[danmart77]

Mark that's a tough call. If you haven't put down anymore more flooring than you show in the photo, you can still put in additional piers if you aren't sure. If you are certain where your heavy machine will sit, its now or never for the support pier/piers.

 

[Roy G]

Mark, one way to spread the load out is to put bracing between the joists.

Roy G

 

[Rwe2156]

Maximum load bearing is obviously directly over a support beam. So at least its going to be close to close to the wall. Me, I would stick a 4x4 post directly underneath just because....

I also have a big planer like that 785#. Its on a mobile base, and I have never moved it once in 15 years.

You're not going to want to move in your situation anyway, so I would take if off the mobile base. Doing that will take the weight off the wheels. Other than that I would double up the ply.

 

[chris_goris]

I am getting a new 20" planer and wondering if I need to beef up the flooring in my shop. My current 15" planer is ~655 pounds, the new machine will be ~875 pounds. The 20" planer will be on a mobile base.

My shop is on a crawl space with 3/4" Advantech flooring on 2x10 joists, 16 oc. There is a main beam down the center of the building made from three 2x10 with another board (2x6?) on top. The center beam sits on two piers and the outside walls. The beam span is ~26 feet, the joists are ~11 feet from the beam to the outside walls. The planer will be approximately centered over the main beam about 3 feet from the outside wall.

So the question is, do I need to add more support to that section of the floor? And if so, what is the best way to do that?

Floor load bearing is all about pounds per sq foot. Ive never met you but Id be willing to bet that YOU weigh more per sq ft than your new planer.

 

[JimD]

You can google up span tables and get a pretty good idea of where you stand. My quick look indicates that 2x10s on 16 inch spacing with a 11 foot span is a very solid floor, capable of supporting over 100 lbs/square foot. I have to interpolate (or calculate) so this is rough but I think their deflection would be about at the 1 in 360 point (the common limit) at 140 lbs per square foot. So to support 875 lbs, the load would need to be spread over about 6.25 square feet (a little more than 3x2 feet base). Deflection is also greatest at mid-span. If the planner is near a wall or beam, deflection will be less. There is also nothing that says you have to have 1 in 360 deflection as the limit. That limit would be a little less than 3/8 deflection with the maximum load at exactly mid span. And these tables are not about point loads, they are about having the specified load all over the floor. Since we have to have walkways, we don't have the total floor covered by tools.

So I think the bottom line is you seem to be fine. The floor joists will easily support this sort of load. I didn't check the beam but I assume it will take similar loads (but there are handy tables for that too available on-line). For almost all situations, the worst case is the deflection might be higher than we want, not a floor joist breaking. We have to get way over loaded before failure is a possibility. But I don't think even deflection should be an issue. Easiest way to be absolutely sure would be to put a post and beam under the tool. But that would only make sense if it is near mid-span on either the floor joists or the beam supporting them.

 

[MarkE]

Mark that's a tough call. If you haven't put down anymore more flooring than you show in the photo, you can still put in additional piers if you aren't sure. If you are certain where your heavy machine will sit, its now or never for the support pier/piers.

To clarify, those are old pictures from when the shop was being built, included here just to show the floor construction.

 

[MarkE]

Maximum load bearing is obviously directly over a support beam. So at least its going to be close to close to the wall. Me, I would stick a 4x4 post directly underneath just because....

I also have a big planer like that 785#. Its on a mobile base, and I have never moved it once in 15 years.

You're not going to want to move in your situation anyway, so I would take if off the mobile base. Doing that will take the weight off the wheels. Other than that I would double up the ply.

The reason for the mobile base is because the planer will be in front of the double doors at that end of the shop. I sometimes need to roll the planer to the side to bring in or out large items/projects. Not sure if taking it off the mobile base would make much difference. On the base it would be sitting on four wheels (or two wheels and two feet), off the base it would be sitting on the planers leveling feet. Either way, it would still be four points of contact.

 

[Jeff]

Your new Grizzly planer is model #1033X weighing 875#. The footprint of that machine is 22 x 28 (4.28 square feet) or 204#/sq ft.

Other structural engineering folks can comment using that load.

 

[SteveHall]

You could probably add a few more joists between the ones you have under the area of concern if you are worried about excessive deflection. But 800 lbs is only about three burly woodworkers.

However, I do worry about the 220 lbs on a hard, curved wheel. It's bears on <1 square inch and will destroy soft wood flooring as you roll it across. (A soft, large rubber wheel will bear over a larger area but be harder to roll.) What's your flooring finish? Oak and hard maple are hard enough to resist denting. Also, vinyl composition tile (VCT) is cheap and >80% limestone. Even if you didn't want to cover the planer motion area, you could slip a 3" square VCT color sample under each wheel to avoid marring your floor while it rests. Temporarily lay down loose 12" square VCT tiles to roll it across on rare occasions.

 

[chris_goris]

204#/sq ft.

Like I said before, probably about the same as a person standing there......

 

[MarkE]

Floor load bearing is all about pounds per sq foot. Ive never met you but Id be willing to bet that YOU weigh more per sq ft than your new planer.

800 lbs is only about three burly woodworkers.

For the record, I am only about 190 (most days). :rotflm:

 

[MarkE]

You could probably add a few more joists between the ones you have under the area of concern if you are worried about excessive deflection. But 800 lbs is only about three burly woodworkers.

However, I do worry about the 220 lbs on a hard, curved wheel. It's bears on <1 square inch and will destroy soft wood flooring as you roll it across. (A soft, large rubber wheel will bear over a larger area but be harder to roll.) What's your flooring finish? Oak and hard maple are hard enough to resist denting. Also, vinyl composition tile (VCT) is cheap and >80% limestone. Even if you didn't want to cover the planer motion area, you could slip a 3" square VCT color sample under each wheel to avoid marring your floor while it rests. Temporarily lay down loose 12" square VCT tiles to roll it across on rare occasions.

This is the mobile base I will be using. It has pretty wide steel casters.
http://www.grizzly.com/products/Shop-Fox-Super-Heavy-Duty-Mobile-Base/D2058A

The flooring is just 3/4" Advantech with no finish other than what it comes with. I am not overly concerned about marring the floor and the planer will only be moved as needed, which is not very often.

 

[rcarmac]

If you are too concerned about it, I have a concrete slab in my shop that could easily handle it. So I could come and take that worry off your mind.

 

[Skymaster]

Same hers full slab, will hold without a problem. IF the builders haven't already done so , that floor should have solid bridging, every 2 ft ish and they should already know that.

 

[Jeff]

Same hers full slab, will hold without a problem. IF the builders haven't already done so , that floor should have solid bridging, every 2 ft ish and they should already know that.

I didn't know that bridging was used very much these days. I know what they're supposed to do but see mixed reports on their need.

 

[MarkE]

If you are too concerned about it, I have a concrete slab in my shop that could easily handle it. So I could come and take that worry off your mind.

Such a kind and generous offer. :rotflm:

 

[bowman]

Such a kind and generous offer. :rotflm:

I'm quite sure he would fire it up for you on occasion just so it doesn't start gathering rust...

 

[JimD]

Since it seems like you might be higher than the joists can handle if the whole joist span(s) had that same loading, it is worthwhile considering what else is nearby, supported by the same floor joists. In other words, I still think there is no problem as long as there is not another heavy tool close enough to load the same floor joists. If there are, then it could be worth drawing up a little force diagram to check loads. At 22 inches wide at the base, you have to be over at least 2 floor joists. Each joist can take an evenly supported load of about 2,000 lbs. This is not an evenly supported load (it is more of a point load) but this gives you an idea why I think it is still not an issue.