Hi All

 

I was considering getting a 2 post lift in my garage but the floor is only 4" thick. The guys that fit them recommend a minimum of 6". Long story short, I would need to cut the floor and put in 2 large holes and fill them with deeper, stronger concrete.

As its a bit of a hassle, and going to increase costs I am considering a mobile lift such as a QuickJack, either the 5000lb or 7000lb (future proof for heavy electric vehicles).

 

Has anyone used one of these? Any good or is there an alternative or should I persevere with the floor upgrade and a 2 post?

 

Cheers

 

Dave

Don’t know anything about car lifts, but if you go down the Quickjack route, Costco has them cheaper.

I'm sure there are plenty that have been installed onto floors your thickness, I bet many times their installation engineers have arrived on site to find something much less than they have specified despite the client signing to say that their floor complies.

 

In your shoes knowing that the floor is thinner I would have some steel spreader plates made up drilled to suit the ramp fixings and other fixing holes around the periphery for chemical resin anchors, they need to spread the load longitudinally and not from side to side, that is where the forces will be with an unbalanced lift.

Have the suppliers specified what strength the 150 mm of concrete should be? Do you then know what strength was used on your garage floor?

 

2 hours ago, chimaera said:

Have the suppliers specified what strength the 150 mm of concrete should be? Do you then know what strength was used on your garage floor?

 

It should be   2 x 1m x 1m holes by 12" deep. Minimum purchase is 1m cubic metre so I was going to do  2 holes of 1m x 1m x 18" (0.5m) deep to give the 2 x 0.5 cubic metres. It would be C40 spec (just under 6000 psi).

 

Not sure what the current floor is but it is reinforced with steel mesh.

 

 

if you dont know what the existing floor strength is, or whats underneath the floor, absolutely go as deep as you can. even with the quickjack, if the floor is that thin and unknown strength on unknown subgrade you could have a very messy accident..

2 hours ago, mac11irl said:

if you dont know what the existing floor strength is, or whats underneath the floor, absolutely go as deep as you can. even with the quickjack, if the floor is that thin and unknown strength on unknown subgrade you could have a very messy accident..

 

True but if the floor has some A393 mesh or similar in it then the bending strength should hopefully be there across the slab...

 

Personally a 1m x 1m square pad 12" deep in mass C40 concrete doesn't sound adequate to me - I'd be looking for a much bigger slab with mesh reinforcement before I climbed under a lift...

23 hours ago, skomaz said:

 

True but if the floor has some A393 mesh or similar in it then the bending strength should hopefully be there across the slab...

 

Personally a 1m x 1m square pad 12" deep in mass C40 concrete doesn't sound adequate to me - I'd be looking for a much bigger slab with mesh reinforcement before I climbed under a lift...

 

Its firm clay underneath the garage. The existing floor 8m x 6m is 4" deep with steel mesh in it.

 

I had planned on 1m x 1m x 18" (0.5m) deep C40 concrete with M12, 160mm rebar pins fixed with resin, 80mm  into the existing floor around the square holes to tie the new concrete into the existing floor. The new concrete would also have M12 rebar in it.

 

Thinking of the quickjack 7000, depending if it fits under all the cars. It would let me do all the suspension, brakes, servicing etc although would still need to get on the floor. The good thing is it can be put away leaving the garage clear. Less than half of the cost to put a 2 post lift in too.

 

https://www.costco.co.uk/Tyres-Automotive/Garage/Trolley-Jacks-Axle-Stands/QuickJack-Portable-Automatic-Car-Lift-System-Jack-3175kg-Capacity-Model-BL-7000SLX/p/315645

 

What you were planning wrt your original proposal sounds much better but the quickjack is probably better again as it won't entail messing with the floor.  The only requirement seems to be a level floor that can withstand 500psi, which in new money woudl be equivalent to about a C4 mix concrete, so even lean mix C7.5 would suffice and what you have already will be well above that and reinforced as well.

yup... the quickjack load spread is much better than the 2 post option....