Car Lift Ceiling Height and Concrete Guide: What the Manuals Require

Concrete: what the manuals require

Maker and lift	Requirement, as stated	Source
BendPak 10AP two-post	Steel-reinforced concrete, minimum 4.25 in (108 mm) thick, 3,000 PSI minimum compressive strength, cured a minimum of 28 days; flat and level; not on cracked or defective concrete; anchor bolts more than 6 in (152 mm) from cracks, expansion joints and walls; only on concrete, never asphalt; consult a concrete specialist early	10AP installation manual
BendPak, all lifts	Never on hand-mixed concrete; not on expansion seams or cracked concrete; 3/4 in anchors at least 6 in from any expansion seam; not on a secondary floor level without the building architect's written authorization and BendPak's approval; existing floors should be test drilled for thickness and core sampled for compressive strength; a concrete specialist accounts for national, state and local codes and seismic requirements	bendpak.com concrete requirements page
BendPak two-post series table (GP-7, XPR-9, XPR-10)	4 1/4 in thickness, 3,000 PSI with 28-day aging, #6 rebar at 12 in spacing	BendPak Concrete Slab Requirements PDF (2019)
MaxJax M7K portable two-post	Compressive strength 3,000 PSI minimum; the anchor section refers to a 4.25 in (108 mm) slab as the approved practice for its drop-in anchors; reject cracked or defective concrete; flat floor with no more than 3 degrees of slope; shims under the posts to no more than 1/8 in; no anchors within 6 in of expansion seams, control joints or other inconsistencies; never cut or drill a post-tensioned slab; never on hand-mixed concrete; not on a secondary floor level	M7K installation manual
Atlas 9KOHX two-post	A minimum of 4 inches of concrete rated at 3,000 PSI (dealer's wording of the Atlas requirement)	Mechanic Superstore listing
BendPak HD-9 four-post	The product page calls it a freestanding design and links to the concrete page; the HD-9 manual governs	bendpak.com product page
QuickJack 6000TL, 8000TL	No concrete figure on the product pages; the frames are not anchored; a dealer describes a slope limit under 3 degrees	quickjack.com; dealer listing

Three points from that table. Thickness and strength are not negotiable with the makers that state them, and a typical residential garage slab is poured at a nominal 4 inches, which is under BendPak's 4.25 and at Atlas's 4; what yours is, only a test drill tells you, and BendPak says to drill. A post-tensioned slab (common in newer tract housing in some regions; the stamp is usually at the slab edge or on the plans) must never be drilled, per the MaxJax manual, which ends the two-post conversation and leaves the four-post, scissor and portable lifts that do not anchor. And every maker's answer to "will my slab do" is a concrete specialist and the building plans, not a forum.

Ceiling: the arithmetic

Two checks. First, the lift's overall height has to clear the lowest thing over the bay: the joists, the door track, the opener, a light. Second, at full rise the vehicle's roof has to clear the ceiling: the MaxJax manual requires a minimum of 1 inch above the tallest vehicle at maximum rise, and BendPak's 10AP has an overhead shutoff bar at 139.5 inches that stops the lift when the roof touches it. Usable rise is the smaller of the lift's rated rise and (ceiling minus vehicle height minus margin minus pad height). The calculator runs both checks.

Overall height and rise of the lifts in our guides

Lift	Overall height (in)	Rise or max lifting height (in)	Footprint (in)	Source
BendPak 10AP two-post	145 (overhead switch at 139.5)	Rise 69; max lifting height with pad 82.5; min pad 4	Width 135 to 145; inside columns 108.5 to 118.5; drive-thru 92 to 102	bendpak.com
BendPak 9APF low-ceiling two-post	123	Rise 70; max with pad 73.5; min pad 4.5	Width 136 to 146	bendpak.com
Atlas 9KOHX two-post	138 or 142 (two column settings)	74 without adapters, 81 with; min arm 4	Width 134.5; inside columns 110; drive-thru 100 symmetric, 90 asymmetric	Dealer listing
MaxJax M7K portable two-post	89.5	47.25 with pad; min pad 5.5 (table) or 4.75 (description)	Width 105 to 135; drive-thru 74 to 104	bendpak.com
BendPak HD-9 four-post	88	Rise 70; max lifting height 75; runway lowered 5	Width 110.25; length 200.5 overall, 174 outside; runways 158.25 long, 19 wide	bendpak.com
Atlas Garage Pro 8000 four-post	Columns 83	72 to top of runway; 67 under runway	Width 115 with motor; length 206.75 with ramp; runways 165.75 long	Dealer listing
BendPak MD-6XP mid-rise	None (floor unit)	47 without adapters; lowered 4.75	Portable, caster kit	Sales sheet
QuickJack 6000TL / 8000TL / 8000TLX	None (floor frames)	24 (6000TL); 24.5 (8000TL); 24 to 24.5 (8000TLX); lowered 3.5	Frames 70 / 70.75 / 76 long; lift point spread 37 to 60 (TL), 43 to 66 (TLX)	quickjack.com

Which lift fits which ceiling

Inference from the makers' figures above, not a maker's claim. An 8-foot ceiling (96 inches) fits the QuickJacks and the MD-6XP with any car, the HD-9 and Garage Pro 8000 by column height with a sedan parked on top but not driven under, and the MaxJax M7K with its 89.5-inch columns and a car raised about 30 inches before a 60-inch roof meets the ceiling. A 9-foot ceiling (108) raises the MaxJax to its full 47 inches on a sedan and lets the four-posts lift a sedan to the point the roof touches. A 10-foot ceiling (120) is where the BendPak 9APF's 123-inch columns still do not fit and a 12-foot ceiling (144) is where the 10AP's 145 inches do not, which is why BendPak sells the 10AP in standard, 168-inch and 181-inch column heights and the 9APF for low ceilings. Measure, do not assume: the 10AP's shutoff bar sits at 139.5, under a 144-inch ceiling, but the columns are 145.

Measuring the garage

Ceiling: the lowest point over the bay, not the highest; the door in its open position and its track are usually the lowest, then the opener, then a light. Width: the bay wall to wall at the column positions, then subtract the lift's overall width for what is left to open doors (the 10AP needs 135 to 145 inches of width before a door opens). Length: a four-post's overall length with ramps (the HD-9 is 200.5 inches, more than 16 feet) against the bay's depth with the door closed. Floor: level across the column positions (MaxJax allows 1/8 inch of shim and 3 degrees of slope; most garage floors slope toward the door by design, so measure the fall across the lift's footprint, not the whole floor). Slab: thickness by test drill at the column positions (BendPak), the plans for rebar and post-tensioning, and a core sample if the strength is unknown. Power: the circuit, in the electrical guide.

What to do about a slab that fails

The makers' answer is to cut out the column footprints and pour new pads to specification, under a concrete specialist, with the pads tied into the slab per the specialist's design; BendPak's page says to consult one early and that its recommendations are generic and adjusted locally. Our answer is simpler: if the slab is not what the two-post needs and you are not going to pour, buy a lift that does not anchor. The portable lifts, the scissor lifts and the freestanding four-posts exist for that garage.