EZCarLift

[duncan]

Sorry to hijack the thread, but I am a wee bit confused about the type & thickness of concrete required for a four post lift, or any other ramp with legs.

 

I quite appreciate what has been written on other posts, but why do you need extra thickness etc for a lift when the car is standing on 4 tyres of about the same area ? Some ramps seem to have smaller feet footprints which logically would seem worse than tyres. Is there a maximum weight of car / pickup that you can keep in an ordinary garage ?

 

[Motorsport Mickey]

For the fitment of any lift you should always comply with what the lift manufacturers recommend for concrete quality and thickness.

In the absence of confirmed information about a garage base already laid these are the points which I consider pertinent, you are advised to consider whether you think them comprehensive enough before trusting your life to them.

 

A 4 post lift will broadly put a load bearing down through it's 4 contact points of the car plus the weight of the lift itself, and so the concrete quality used for a normal garage base MAY be ok. There is so much variability that can happen when the garage bases are laid that unless you specify it or supervise it happening and observe it, or if you buy a house previously owned by others it's as well NOT to assume that the base will be strong enough. You can plumb the depth of the base by drilling and checking upon depth of material before hardcore or earth is reached (150mm in my case), or sometimes a device used for cable and drain searching may possibly give you a reading of base thickness. The quality of the concrete used can be gauged by it's colour of dust when drilled, dark grey normally being better but of course you'll have no indication of whether there is enough or indeed any steel reinforcing's sunk into it's layer.

A scissor lift either in it's 1 metre restricted height form which folds into it's own "cassette" feet which are about 1.5 metre long by 500mm wide

 

 

 

give a much easier accommodated "footprint", the weight of the car being spread over a larger area than when it's on it's tyres, and only the weight of the lift being an extra (about 580 kgs but they do vary and should be confirmed. A full size scissor lift with a 6 ' clearance underneath will again normally spread it's weight over a larger area and be easier to accommodate safely.

The most problematic will be a two post lift which requires very high quality concrete with reinforcement (not normally laid for a garage base unless specified, it's costly) to withstand the magnified loadings that only two small points of contact put on the floor ie: weight of the lift plus the weight of the car plus the leverage forces of the car on arms divided by 2. Make no mistake, if you don't specify the floor correctly or take a chance that others have done it previously (why would they pay for it ?) the car will try and kill you.

Whichever lift you choose make sure the bases for the lifts are secured to the lift manufacturers recommendations with probably 5 anchor bolts per foot, it's tempting to think a 4 post is inherently stable but without bolts bad things can happen.

 

 

Mick Richards

Edited August 20, 2017 by Motorsport Mickey

[Paul Down]

Sorry to hijack the thread, but I am a wee bit confused about the type & thickness of concrete required for a four post lift, or any other ramp with legs.

 

I quite appreciate what has been written on other posts, but why do you need extra thickness etc for a lift when the car is standing on 4 tyres of about the same area ? Some ramps seem to have smaller feet footprints which logically would seem worse than tyres. Is there a maximum weight of car / pickup that you can keep in an ordinary garage ?

 

 

If you inadvertently rock the car( e.g. while removing a hub nut) while parked in your garage on its tyres nothing amiss will happen, repeat the scenario with the 1 ton car ( plus 1/2 ton or so for the lift) at a height of 5ft and the turning moment on the 4 post leg fixings will be high.

 

As MM has said you ignore the manufacturers recommendations at your peril.

[Eddie Cairns]

Agreed with a lot of what the guys above have said and I will repeats a good few comments

 

Older installations will have 75mm to 100mm depth of concrete, 3 inches to 4 inches in old money.

 

The hard core and sand layer underneath the concrete will probably not have been compacted or reinforcement used in the concrete slab.

 

The concrete will probably not have been power floated to aid compaction, it was only for a garage.

 

It is very unlikely the existing owner will have the specification of the concrete used.

 

The guys who fitted my 2 post lift advised that in 25% to 30% of installations they visit, they have to refuse to install 2 post lifts until the concrete has been replaced. In a lot of cases they can tell from the free and easy way their drill goes through the concrete, that there is very little strength left in the concrete

 

As already said both scissor lifts and 4 post lifts do not exert bending forces on the concrete floor, therefore a new 150mm / 6" fibre reinforced 30 newtons per square mm concrete slab with the hard core and sand layer compacted and the concrete power floated will provide a good base for theses lifts but to be honest a quick check by a civil engineer will not be expensive to confirm the specification of the floor.

 

Note to obtain the specified concrete quality mixing by hand or in a small mixer is not suitable to achieve the required properties in the concrete.

 

As advised previously, a 2 post lift exerts large bending moments on the concrete foundation concrete bolt interface and at least 8" / 200mm of 30 newton / square mm concrete with probably both fibre and reinforced mesh in it is required. Again even you are given a floor detail by the lift vendor getting a qualified engineer to give that the once over is required and not expensive.

 

If you have an old floor to install the lift on it is acceptable to remove sections of the concrete floor and pour higher quality sections around 1 mtr deep but this must be specified by a civil engineer and is regularly done in workshops where there is a requirement for a 2 post lift.

 

You will have to leave the concrete for around a month to harden before installing a lift but the engineer will be better able to provide advice.

Edited August 20, 2017 by Eddie Cairns

[john.r.davies]

I've asked the mods to separate off the last posts from the original thread as, yes,it was a complete thread hijack, and the OP's proposal of a group discount is being lost!

 

John

[Dave Ashworth]

Did anyone notice the Amphicar on the lift in video on the home page of EZCarLift website?

 

Cheers.

 

Dave.