Installing a lift on sloped concrete?

[pumalex]

Hey everyone, asking the lift installation experts here. I have seen a good thread here on garagejournal and i have contacted Jeff at bendpack to get further explanation of his points and he was great helping me. I would like to see what you guys have to say about his solution. Since the thread is not active anymore, i decided to start a new one instead of reviving the old one. Here it is for reference.

http://www.garagejournal.com/forum/showthread.php?t=65457&highlight=plumbness

I am going to be installing a 2 posts "base plate" low ceiling lift in my garage and I am very unsure of the installation. I have a center drain in the garage so I have a slope in the floor.

Here is a drawing of what I mean and a picture of the type of lift I want

If I rest the post directly on the ground and put them level, I am going to have arms that are not the same height and the arm of the lowest post with the angle of the floor will probably hit the base plate.

Now the first thing that comes to mind is to shim the lower post so that it comes to the same height as the other one. The problem is that the base plate which is resting on the floor is going to be too low and probably hitting the mechanism under it so I would have to shim the base plate also which is truly not something easy. It comes even worst in the fact that the car is going to be 1 inch lower on the side of the post that was raised in relation to the arms since the car is resting on the sloped floor. We all know that 1 inch on a sports car like a Porsche makes night and day difference in being able to put the arms under the car.

Here is a picture of what I am talking about.

Now what i was suggested by Jeff at Bendpack is to live with the slope and just make sure the posts are parallel and that the arms when fully extended are in line one to each other. What this means is that the posts would be parallel but not plumb (level vertically, don't know if it's the right word).

Of course the drawing is way to dramatic and obviously the angle wouldn't be so big, if I have an inch of slope from side to side, that would mean that my post would be about ¾ of from vertical level from top to bottom. This translate to about 0,5 deg off from level.

He said that the stress on the bolts would not be enough to create any problem with that kind of installation. What I see though is that the car is going to be lifted parallel to the floor so at a 0,5 deg side to side, which is not level.

This would make things 10x easier but is it safe enough? Than again, is putting a 1 inch thick steel plate under a post as a shim safe?

What do you guys think about it and what should I do? I really want to avoid pouring a new slab as this one doesn't even have a year and when I designed the garage, there was no lift in mind but now plans have changed and I am trying to adapt the best I can.

Thanks for you help and a special thanks to Jeff at Benpack, customer service goes a long way... Promise i'll post some pictures when the garage is finished, it will look more like a showroom than a garage but this is all you fault, this damn website

 

[HemiRambler]

Where I work we use a self leveling grout - Extra Fluid Micorox to level floors for hospital scanners (Cat Scanners, MRI's stuff like that). Micorox is a self leveling 2 part epoxy. It will not get it "perfect" but darned close. Way close enough for what you are doing. It has very high compressive strength ratings (~60ksi IIRC) and is relatively easy to work with. There are a number of ways to install it, but basically you make a dam and pour directly on your floor. You can put a release agent under it or not depending on your future plans. Don't let the "dam" detour you - it's a simple process I can walk you thru if you're interested.

If this sounds interesting give them a call and see what their thoughts are - personally I wouldn't hesitate to try it, but calling them & discussing it with the professionals has got to be better than an endorsement by some yah hoo on the web. If by some chance you decide to try this - let me know - we have "perfected" the "pour" to some degree allowing more consistent results than just pouring it and hoping for the best.

FWIW I know nothing about installing a lift.

 

[pumalex]

yeah this is an option but if i was to opt for this, i would have to do the complete floor or else i would end up with the garage divided in two with one part being and inch higher than the other. The other choice would be to get rid of the drain but then again, here in Canada with all that snow, you have to send that slush somewhere when it melts.

 

[LSVLance]

My lift at work is on a sloped floor, but sloped front to back...and it is a pain in the ****. It is shimmed so the columns are plumb and the back lift arms are like 3" off the floor when the front ones are touching the floor. REALLY makes it difficult to get the arms under a low car.

In your case, I'd really be tempted to bolt the baseplates flat to the floor, keeping the columns parallel and the arms flat to the floor. As long as the lift supplier is cool with the columns not being plumb and level.

 

[IH82BL8]

yeah this is an option but if i was to opt for this, i would have to do the complete floor or else i would end up with the garage divided in two with one part being and inch higher than the other.

Would it be possible to build up the concrete or use some kind of spacer under the lift footprint?

 

[jhelrey]

Our shop has them shimmed up. Some spots are up one inch. It is noticeable when the arms are fully on the ground. Never been an issue putting a vehicle on or off.

 

[carpenter383]

Have you considered grinding/cutting 1" out of the floor where the "higher" post will sit?

 

[pumalex]

Have you considered grinding/cutting 1" out of the floor where the "higher" post will sit?

thing is that the arms of that post will touch the floor, i would have to grind all the floor to make it level, including the center plate between the posts. I don't know if such a thing exists.

 

[pumalex]

Would it be possible to build up the concrete or use some kind of spacer under the lift footprint?

probably but that would equal to putting the steel shim under the low post.

 

[nissan_crawler]

My preference (assuming you have the floor thickness to do so), would be to recess the high post into the concrete as much as you can, without the lift arm dragging the floor, then raise the other post to match. Worst comes to worst, if a car is too low to get over the arm on the low side of the floor, get a 2x12, and cut a nice angle on one end of it, and lay it on the floor on that side. Drive the car on it, swing the arms under, lift car, pull board out, go on with life. You're going to have to deal with a compromise one way or the other. A chunk of 2x12 seems like a pretty easy one to me.

Edit: I don't know anything about the lift you specified, does it have locks at certain heights on the post? If so, I would sure want them level, myself.

 

[Zengineer]

Cut a rectangular hole under each post with concrete saw/circular saw with diamond blade. Break the concrete up. Dig down 10" or so. Repour the pad area for each, level this time.

Shouldn't take more than a few hours to fix the problem.

 

[Ign]

Here is a drawing of what I mean and a picture of the type of lift I want

This is almost exactly my situation. My pad is not supposed to have a slope, it's just poor craftsmanship. It's not a big problem for me, but because my "slope" is more wavy or stepped, it's not identical to your problem. The arms on the lower column scrape along the floor as I swing them, but the ones on the higher side still hug the floor pretty good - never actually measured how much space is under there.....then again I've never had anything smaller or lower than a GMC Canyon on my lift.

 

[lsupcar]

I had similar concerns when I was considering installing a lift, and also analysed many such details. Your profile does not list where you live, but have you considered having a professional install it for you? That is what I did for a very reasonable price, and the lift was installed in a way that eliminated all my concerns. I would suggest looking into this, and let someone who has previously delt with and solved this problem in the past, take the worry out of your install. Then you would know it is safely installed and adjusted and have someone to call for questions after the fact. The price would also likely be less then you would expect. No matter what, enjoy your new lift.
Bill

 

[Vicegrip]

Don't over think this too much. 1 inch is nothing. Get the lift, install it and enjoy it. It is a car lift not the space shuttle. Shim the posts level to earth and lift the low side post a little with shim stacks and you will find that the arms end up real close to level with each other. You can chip out the hight side post base area a little as well if you feel like it. by the time you get finished shimming I bet you will find the arms in good shape. The equalizer cables all need to be tuned to the install anyway. Tune the cables per the manufactures instructions to fine tune the arms. Once all is done pack grout under the lifted side if there is a gap. Do this last in case you need to tweak anything.

 

[pumalex]

yeah i guess i should try to take my measurment as precise as possible to see how bad it is, how do you guys verify level on a 12' floor? Should i rent a laser or something?

i don't think I'll be able to find a 2x4 straight enough to take some accurate measures.

 

[Old61]

yeah i guess i should try to take my measurment as precise as possible to see how bad it is, how do you guys verify level on a 12' floor? Should i rent a laser or something?

i don't think I'll be able to find a 2x4 straight enough to take some accurate measures.

Run a taut string wound around 2 bricks of the same size or similar across the distance. A 4 foot level with one end steadied on the high side brick - measure from string to bottom of the other end of the level, multiply that times 3 if 12' distance.

 

[Ign]

yeah i guess i should try to take my measurment as precise as possible to see how bad it is, how do you guys verify level on a 12' floor? Should i rent a laser or something?

i don't think I'll be able to find a 2x4 straight enough to take some accurate measures.

Well, if you really want to run a straight edge a full 12' then yeah, you'll need a 12' straight edge. If you can assume the slope is relatively consistent, put a 4' or preferably 6' level in the center of what would be the lift posts, then put an angle finder on that. Say you find 1 degree of slope, then it's just a simple right triangle, where your angle A is 1, solving for edge a

http://www.cleavebooks.co.uk/scol/calrtri.htm

My Craftsman digi level also has a laser which it states is 1 1/8" above the bottom of the level, so you can also place that where one post would be, set something on the opposite side to simulate the other post. Make sure the level is, well, level (0 degrees) and the dot should be 1 1/8" off the concrete on the other side. If not, the difference is.......the difference. I've had surprisingly good luck doing this to align gate halves on a 17' span.

 

[jhelrey]

String line! Pound a nail on the one side of the garage and tie the line. Go to the other side with a string line level and have someone move it up and down until level. Put nail in, etc.

Take a tape and start making measurements from the string.

 

[pumalex]

yeah i guess that was easier than i thought, thanks i'll try that.

 

[1320stang]

When they install light poles, they don't touch the concrete pillar they are bolted to, the base plate has a nut on the bottom and the top, this way they can plumb the pole.

My thought it to do this, then once it's done, pound some steel shims under the plates and grout them in.

But I'm no lift expert and I didn't stay in a Holiday Inn Express last night.

 

[henrysgarage]

When we did a friends like we had to shim for plumb etc and never had any issues. Install it level and plumb and use it.

 

[racerock]

SOOOO, if my concrete seems to be say within 3/8 level on an 11' span, it is good do go and don't need to consider a shim plate for one of the posts?

It appears really close to true level (bubble is in the middle of the level, but is slightly to the one side)

 

[Daniel Dudley]

Yup. Cut a shim plate, or use big washers and then grout it with the heavy duty stuff.

 

[m.james]

Leveling out where the posts will be placed, is probably your best option that way it lifts absolutely vertical.