My slab will be 4.00" but I'll have 36" squares of 8.00" thick where the lift legs will be anchored, and I'm shoring them up with some re-bar as well.

Wow, why so thin for shop?, it's not a side walk.

I always thought these were interesting....

Pretty standard around here, I have 5 friends in the area with 4.00" floors in thier shops, they hold up just fine (actually 4.5" is where mine will be). Bed of 12.00" compacted crushed rock, .006 vapor barrier, 2.25" thick foam sheets, 6"x 6" steel wire grid mesh on top of the foam, 5/8" PEX tubing for the radiant heat, a grid of 1/2" rebar on 12.00" centers above the tubing. 5 sack mix concrete and It'll be PLENTY strong for home shop use.

That will hold up fine....I oversee all construction for a fairly large city...and many of our older fire stations only use 8" of concrete in a fire station apparatus bay floor....and fire trucks are pretty darn heavy.

The only problem I see with that is the anchors going into the PEX tubing for the radiant heat. I have a thicker floor than that and I still have decided a 4 post is best for me. I wish I had heat in the shop floor, but I am happy with what I have.

I routed the PEX around the areas that will have hoist pads and marked the corners so there will be no chance of drilling through PEX.

:
Two post all the way!
Four post if you mostly use it to store you car. (ONLY because of ease of just driving up onto ramps) you can store on a two post too.

I store my car on my two post.

The Ramcharger will be spending a lot of time on the 4 post as I need to box the frame for strength, just like in the picture below. After it will move on its own I will be using the lift for servicing the fleet. Another reason for the 4 post is that I live in earthquake country and I really don't need to store anything up high. My '64 Polara had its wheels off and was resting on four super duty jack stands when we had the Nisqually Quake and I expected it to be on the ground when I got home, but it was still on the stands.

How tall our your ceilings those with lifts? I plan to add a 20x 20 bay on my shop...me current ceiling is 10'... do I need to go 12'...14'..??

Only will store RR and Charger....

I have a 14.00" Ceiling but if I could have gone to 16.00" I would have (city wouldn't allow a higher wall). 14.00" ceilings are fine for most anything inside on a lift, but with a 2 foot minimum for roll up doors it gives me a max door opening height of 12.00' which is boarder line for some of the taller RV's air conditioning units etc. Not an immediate issue, probably ever for me, but if I sell it all someday it could be one for a future owner.

I am looking at this one

https://www.eagleequip.com/product/MS-8000XLT.html

The measurement guide seems to show 12' ceiling will be fine... I wont have a door...its a drive in bay attached to my current shop...??

I have that lift, and a BendPak HD9XW in my garage-which has a 10' 9" ceiling. Zero issues with a 1969 GTX in the bottom and a 1967 Newport on the top (on the BendPak). Plenty of extra clearance on the top and bottom.

For WIW, I would not buy that Eagle lift: buy a BendPak. Having both, it is CLEAR where the extra 1k went into the BendPak. I would never put my GTX or Newport on the Eagle.

well I've heard a lot about shops but need more manufactures on 4 post lifts. Stopped in Warren Ohio today at Back yard buddy. I like the looks of there lifts. Pricey.. but showed me some bent ones in the back from other vendors. some of you guys seem to like the Bendpak. Cant get good pictures of the construction of them. Bendpak looks like the lock is hanging from one bolt at the top? not welded in place or anything, scares me. I like the fact of the back yard buddy has a tube around a tube vs a open 3 sided competitors. My old center post gave up the ghost. want this to store and work. want to stay with a 4 post. like that the back yard buddy is very stable when you grab it and push on it. so what other name bands you guys using? like the buddy but boy the price ! but you cant put a price on safety... thoughts on the lifts you all own.

I don't have my own lift but plan on it eventually.

I did my apprenticeship at a Ford dealer and used both hoists. The 4 post was way more versatile. Depending on vehicle length and frame configuration the 2 post could just get sketchy getting it all set-up an finding the balance points.

Never dropped a car but it happens often enough. A 4 post with a set of jack trays on air was great. Plus when working the hoist gives a nice place to put your tools down.

https://youtu.be/rQj7Y7Q8tU4

Well, the lifts are in! I went with a local vendor, CEM Lifts in Post Falls Idaho. Very good service and fair pricing. I did plenty of homework and these two filled the bill for my needs. The 4 post is a Direct Pro Park 8 PLUS LONG 9,000lb ALI certified portable and will be used primarily for storage, the 2 post is a TLT210-A 10,000 Launch Tech and is also ALI certified. It could have been setup as either Asymmetrical or Symmetrical and I went with Symmetrical to give it more versatility.

this thing is a beauty...is this the same model car that vin diesel used on the fast and the furious movie?...

that's called FSS. Flat Surface Syndrome........

The ProPark 8 is the exact one I am looking at... saw it a Barrett J in Phoenix... Cant wait!!