Strange concrete overpour question

[plumbing101mike]

Hi,
Last year I purchased an old commercial building (my guess is that it was built around 1890). It used to be an egg washing plant from my understanding. It has a wooden floor over a basement. Strong floor, large I-beams (22" deep if I remember correctly), 4x10's layed on their side for the subfloor and then a 3/4" standard hardwood floor over the top of that.

The hardwood is a terrible floor for what I use it for. When I bring my skidloader (Case 1480) in or a trailer inside or even a vehicle the snow melts off, gets the floor wet, and now it has buckled the hardwood. I can see several places where the previous owners have taken the hardwood out and replace it with plywood assumably from the same problem.

I would ultimately like to be able to weld/grind/etc... in here also. I am considering overpouring with concrete.

My main concerns are - total weight. I am thinking that this floor will handle it with no problems at all, but I am not an engineer and this is not an area of expertise for me. Flexing - I do bring my manlift into the building quite regularly which is 9,000#. I also bring my Case 1480 skidloader in and sometimes a trailer or a vehicle. If I do this, the concrete will need to be thick enough to withstand the weight. The area is wedge shaped, but for simplicity let's call it 30'x50'

What are your thoughts? Is this a good idea or foolish? How thick should I go? Fiberglass additive? Mesh? Other, better or more economical suggestions?

Thanks in advance guys!

 

[ishiboo]

Let's see some photos of the building!

 

[Farrier]

You need an engineer

 

[GMCGarage]

could you take the wood out, and use form deck and pour a structural slab? I would be worried over time the wood will rot and fail the slab.

Any pics, dimensions?

I think ultimately you should pay for a design that is correct. Some big loads to worry about.

 

[Chaznsc]

You need an engineer

This......you arent going to be able to span with the concrete so its got to have a support system, and wood isnt it.

 

[ssdave]

You have a very viable support system to install a structural slab. You will need an engineer to design and size it, but that isn't a difficult task, just needs done. Contact a local structural/civil engineer, and talk to them about it.

There are a couple of ways to go with it. One is to calculate the strength of the existing floor, and if adequate, pour a thin reinforced topping slab on it. This would be a high strength concrete with steel staple reinforcement in it at a very high ratio, and maybe some microfiber also. The existing floor would carry the structural load, the concrete would just be a wearing surface and the primary design consideration on it is local deflection and cracking from wheel and point loads. The other is to use the slab itself as a structural member, by using steel pan under the concrete. The existing floor would be shored up during placing and curing of the concrete, and after it cures, the concrete itself would carry the load as well as being the wear surface.

I've designed floors both ways over basements. It just depends on how the floor you have in there calculates out for the loadings which is most suitable.

 

[raffaelli]

I would be very leery of pouring over a questionable wood floor. Get a structural engineer to visit and make some suggestions about flooring removal and replacement with a composite deck.

 

[wssix99]

When you have a problem like this, you need to call an engineer. Any commercial structural engineer should be able to work this out quickly for you.

Just like when you need surgery - you call a doctor.

 

[NUTTSGT]

Our firehouse used to have a wood floor until it was remodeled in the late eighties. They ripped the old wood floor and filled what basement was there with stone and poured a concrete floor.

Done and no question as to what it will hold as far as weight.

 

[plumbing101mike]

You have a very viable support system to install a structural slab. You will need an engineer to design and size it, but that isn't a difficult task, just needs done. Contact a local structural/civil engineer, and talk to them about it.

There are a couple of ways to go with it. One is to calculate the strength of the existing floor, and if adequate, pour a thin reinforced topping slab on it. This would be a high strength concrete with steel staple reinforcement in it at a very high ratio, and maybe some microfiber also. The existing floor would carry the structural load, the concrete would just be a wearing surface and the primary design consideration on it is local deflection and cracking from wheel and point loads. The other is to use the slab itself as a structural member, by using steel pan under the concrete. The existing floor would be shored up during placing and curing of the concrete, and after it cures, the concrete itself would carry the load as well as being the wear surface.

I've designed floors both ways over basements. It just depends on how the floor you have in there calculates out for the loadings which is most suitable.

Thank you! I very much appreciate your detailed response. You (and the rest of the guys here) have convinced me that an engineer is the proper next step.

 

[plumbing101mike]

Let's see some photos of the building!

I had not considered getting photos until you asked for them. Based upon the consensus here, I believe that my next step is an engineer. I will not be getting one in the immediate future, but I believe that the wisdom here is worth following. If I get a chance I will snap and post some pictures.

 

[plumbing101mike]

could you take the wood out, and use form deck and pour a structural slab? I would be worried over time the wood will rot and fail the slab.

Any pics, dimensions?

I think ultimately you should pay for a design that is correct. Some big loads to worry about.

I had not considered the possibility of rotting the wooden subfloor. More reason to involve and engineer. Thank you!

 

[plumbing101mike]

Our firehouse used to have a wood floor until it was remodeled in the late eighties. They ripped the old wood floor and filled what basement was there with stone and poured a concrete floor.

Done and no question as to what it will hold as far as weight.

I do not wish to lose the basement here. It has potential. On one side it is only about 3 feet below the ground and has an old ramp that you could run heavy loads up and down in and out of the basement with. Not perfect by any means, but usable. I am thinking that forks on my skidloader and pallets will make great use of the basement.

 

[plumbing101mike]

Thanks again for all the replies guys!

 

[Charlie51]

I would consider boilerplate rather than concrete.

 

[ard]

Sounds like a cool old building.... Do keep in mind that what you do to it might change the value to downstream owners. Just a consideration.