What type of grout to put under lift posts?

fogged306 · Nov 18, 2013

I just bought my first lift for my shop and will be installing it over the next couple days. I've got a drain that runs the length of my garage right in the center so the concrete is sloped slightly. I'm going to need to space the lift up in some spots to get the posts plumb and I've been reading on here a lot of people suggesting packing grout underneath when you've got them mounted. Any specific type of grout, or are we talking actual tile grout? I've never put one up before, but I have a couple mechanic friends who have many times so they'll be helping me this time around. Any pointers you guys want to throw me would be helpful too. I trust these guys, but having as much info before I get started is the best way to go IMO.

Should mention it's a 10,000lb rotary two post symmetrical lift with an overhead bar.

cwlo · Nov 18, 2013

Its nonshrinking grout, used for the specific purpose of filling a void in a weight bearing application. You can find it in the concrete aisle at Home Depot. They have it in 50lb bag, and also a smaller plastic container (should be what you need). Good Luck,

Chris

readhead · Nov 18, 2013

Use steel shims and nonshrink grout. It is avaliable at HD and concrete supply stores. We use it under column base plates.

nehog · Nov 18, 2013

If the lift is new, Rotary includes shims to do this. If not, you could make some up from virtually anything, believe it or not, the Rotary shims are made from plastic. Me, were I to need shims I'd use steel.

fogged306 · Nov 18, 2013

Nope, it's a used lift and either the shop before me didn't make it plumb, or they had a perfectly flat floor because when I took it out there were no shims underneath. I have a bunch of washers that came with the anchors I bought that I planned on using for shims. Think washers are a good idea or no?

Thanks for the replies on the grout too.

readhead · Nov 18, 2013

Washers are fine. The grout takes the weight. Actually more space is easier to grout.

AndrewDouglasBird · Nov 19, 2013

Why not make a box the size of the lift feet and pour a 1/2" (or less) tall pad in place before installing the lift? Then you would have two flat areas to set the lift on without having to worry about stuff grout underneath.

wssix99 · Nov 19, 2013

You also want to make sure the grout you get is rated for machinery, like this one (Some are not.)

http://www.quikrete.com/productlines/NonShrinkPrecisionGroutPro.asp

toofart · Nov 19, 2013

I used a 5/8" steel plate.

fogged306 · Nov 19, 2013

What is the best method for getting the grout under the lift? So far I've only had time to get one post in place and the holes drilled and anchors placed. I only needed a single washer to get the post plumb so It'll be pretty tough to pack grout under there with the lift in place. Do you push it under there with something like a paint stick, or do you tilt the post back and then trowel some grout down and let the lift back down on top of it to flatten it out?

Also do you torque the anchor bolts down right away or let the grout set first? And is there any specific torque rating I should be aiming for when tightening the anchor bolts? I have 8.5" long 3/4" anchors if that makes any difference, and my concrete floor was 8" deep and I don't know what PSI, but it's extremely hard concrete. Had a hell of a time drilling the holes with a gas fired hammer drill and a fresh masonry bit.

fogged306 · Nov 19, 2013

wssix99 said:
You also want to make sure the grout you get is rated for machinery, like this one (Some are not.)

http://www.quikrete.com/productlines/NonShrinkPrecisionGroutPro.asp

Good to know. Thanks!

koditten · Nov 19, 2013

readhead said:
Washers are fine. The grout takes the weight. Actually more space is easier to grout.

The second part makes no sense. The grout does nothing. The weight is on the shims. The grout is only there to make th etransition from the plate to the concrete look better.

I used plain old silicone bathroom caulk btween my plates and the concrete. If you read the instructions, most say to retorque every 30 days with heavy use. Any ridgid caulk is going to crack from flex and retorquing.

In short, if you have a gap because of un level floor, there better be shims in there. Washers with segments cut out to slide past the bolts work just fine.

FWIW, everyone will have to use shims, no floor is perfectly flat...in most cases.

joes169 · Nov 19, 2013

koditten said:
The second part makes no sense. The grout does nothing. The weight is on the shims. The grout is only there to make th etransition from the plate to the concrete look better.

To be perfectly honest, nothing in this paragraph makes any sense to me.

If using the correct grout, it will transfer ALL the load to the floor, as the shims are only intended to be temporary. We're not talking about caulk here, but a non-shrink grout that is multiple times stronger than the floor itself. If you don't believe that the grout has any structural value, I highly suggest you never step foot in any major structure that contains any kind of steel, as I can guarantee that structure is bearing on non-shrink grout in at least a "few" places.........

quiettfxgt · Nov 20, 2013

It is avaliable at HD and concrete supply stores. We use it under column base plates.

koditten · Nov 20, 2013

The shims are not temporary. They are there for ever. We are not talking steel building structures, we are talking lift. Different things all together.

Geir Tore Simonsen · Nov 20, 2013

The shims can be considered permanent in the sense that removing them would be pointless, but their only purpose is adjustment. Proper grout is much better suited for load bearing, although shims may be sufficient for small loads. I'm about to grout for a movable lift myself, but don't plan on using shims. Instead I'm planning to make four small threaded holes in each base, and do the adjustment by bolts instead for better precision. The adjustment bolts will be removed afterwards.

Sent from my GT-I9100 using Tapatalk

rburke65 · Nov 20, 2013

If the grout didn't carry some of the load, then why would Quik-Crete and others, make a specific mixture for this purpose?

readhead · Nov 20, 2013

The shims are only for erection. They are not for load bearing. The same thing can be accomplished with double nuts but it is a pain in the ***. Grout thickness is usually a maximum of 1 1/2". The gap for the grout allows for uneveness in the concrete. Trying to install non-shrink grout in a skinny space is difficult but possible.
Non-shrink grout is used for steel erection, filling gaps under wood sill plates, under machinery pads and equipment etc. It provides a full bearing surface.

gorilla · Nov 20, 2013

Grout should be about 1/2" thick to properly support a load. If I were installing your lift I would use a nut under each anchor hole and use that to level the posts and make sure that there was about 1/2" clear space under each pad. Then I would build a set of dam's around each leg and pour the grout in until it filled up to the top of the pad. I've used this method to set big machinery for many years and I will tell you that it stops a lot of vibration and alinement problems.

readhead · Nov 20, 2013

1/2" really is about minimum. We have done it that way also by drilling 3 or 4 holes in the baseplate so the grout can get in and the air can get out.
I would guess that most lifts ony have about 25% bearing on the concrete. That is ok and probably taken into account by the designers.

dieselgarage · Nov 20, 2013

I had a crane system pun in a few years back. The columns set on the floor. What they did was put a 2"diameter piece of round stock with one end was a dome under the center of the mounting plate. Then used the mounting studs to kind of rock the plate on the surface of that dome on the slug. That way they could plumb the column with the mounting studs and then grouted the rest of the area under the plate. I thought it was pretty slick

Homerr · Nov 20, 2013

joes169 said:
To be perfectly honest, nothing in this paragraph makes any sense to me.

If using the correct grout, it will transfer ALL the load to the floor, as the shims are only intended to be temporary. We're not talking about caulk here, but a non-shrink grout that is multiple times stronger than the floor itself. If you don't believe that the grout has any structural value, I highly suggest you never step foot in any major structure that contains any kind of steel, as I can guarantee that structure is bearing on non-shrink grout in at least a "few" places.........

I detail building plans and what joes169 said is correct.

fogged306 · Nov 20, 2013

gorilla said:
Grout should be about 1/2" thick to properly support a load. If I were installing your lift I would use a nut under each anchor hole and use that to level the posts and make sure that there was about 1/2" clear space under each pad. Then I would build a set of dam's around each leg and pour the grout in until it filled up to the top of the pad. I've used this method to set big machinery for many years and I will tell you that it stops a lot of vibration and alinement problems.

This would probably explain the large hole in the center of the baseplate. I'm going to do just that.

Unfortunately, the lift only needed one washer on one post and 2 on the other, so I'm nowhere near the 1/2" minimum. I hadn't seen the posts saying that until I already had my posts in place and the anchors mounted. At this point, It'll be damn near impossible to lift the posts off and put nuts underneath to get them up high enough to get the min grout under there. Is ti going to be a waste of time to pour the grout underneath the posts in this case? Luckily I know a guy with a laser table so if worst comes to worst, I'll have him cut me a shim out of stainless.

fogged306 · Nov 20, 2013

As a side story, I went into HD and didn't see any type of load bearing grout so I asked the "floor specialist" and he very condescendingly told me that there was no such thing and that grout was only for tile... Until he looked it up on google and found otherwise, hah.

What type of grout to put under lift posts?

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