I will be getting my shop slab ready for concrete soon. It will have 2 XPS for radiant heating. I will be installing a 4 post lift and leaving the tubing out of the lift column area. Should the XPS be removed as well or can the columns sit on that? Using 25 PSI green board from Lowes. Also going to have a free standing steel mezzanine sitting on the slab with 6 columns bolted down. Wondering the same thing here. On my last shop I removed the foam under my lift columns leaving it thicker but think its better to have more uniform base. Just making sure the foam can support the lift and mezzanine.
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Lift columns over XPS foam
- Thread starter Crawlin
- Start date
theoldwizard1
Well-known member
Not only would I remove the foam, I would dig a 2'x2'x2' footing for the lift footing.
HELLSUNICORN
Well-known member
- Joined
- Jul 20, 2008
- Messages
- 66
I would not leave the foam out. When I did my 2 post I left the foam in but made that section of the concrete thicker and added remesh. I don't know if you need to worry about that with a 4 post. I can tell you to take detailed photos and measurements of the tubing before you pour the concrete. I did not do that and when it came to drilling the holes it was way harder than it needed to be.
I left my foam there, same thickness of 6" throughout slab. I did keep rebar and tubes out of the mounting locations.
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ericm
Well-known member
Don't four post lifts have four large flat feet? Much larger than car tires' contact patches? Even with the weight of lift+car I bet the PSI on the concrete under the lift feet is less it is than under a car's tires.
Also the slab is going to spread out the load on the foam. Not perfectly evenly because it will flex some, but it'll still be over a wide area.
Also the slab is going to spread out the load on the foam. Not perfectly evenly because it will flex some, but it'll still be over a wide area.
Don't four post lifts have four large flat feet? Much larger than car tires' contact patches? Even with the weight of lift+car I bet the PSI on the concrete under the lift feet is less it is than under a car's tires.
Also the slab is going to spread out the load on the foam. Not perfectly evenly because it will flex some, but it'll still be over a wide area.
Yes these are my thoughts as well. Was planning on leaving the foam, just thought I would get some opinions.
like2wheel
Well-known member
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Last edited:
Farmall450
Well-known member
Don't four post lifts have four large flat feet? Much larger than car tires' contact patches? Even with the weight of lift+car I bet the PSI on the concrete under the lift feet is less it is than under a car's tires.
Also the slab is going to spread out the load on the foam. Not perfectly evenly because it will flex some, but it'll still be over a wide area.
What he said ^
25PSI = 3,600 pounds per square foot. What are you planning to lift? Will your hoist lift 7 tons? My backhoe weighs 7 tons but I don't think I'd want to be under it 6' in the air.
Joe H
Yes I am buying a 14k lb rotary lift. Some ton trucks with utility beds are around 13K. I would have no problem standing under that if the lift was rated for enough.