Have I enough concrete?

Passataudi

Hi all, I'm thinking about installing a 2 post garage lift for my own use. I have 5 inch of concrete. Is that enough. What's difference between the H frame and normal 2 post lift. Thanks

Sam Quentin

Call these guys in Dundalk.

http://www.redmount.ie/2-post-lifts

dar_cool

Yes you have enough, is it new concrete or old ? Put a lift down last year in 4" as was recommended and hasnt budged and I've had a few 2+ tonne yokes on it. Enjoy the lift. Best thing ive ever bought

Passataudi

dar_cool wrote: »

Yes you have enough, is it new concrete or old ? Put a lift down last year in 4" as was recommended and hasnt budged and I've had a few 2+ tonne yokes on it. Enjoy the lift. Best thing ive ever bought

Thanks for your reply. I've just been checking out the concrete and there is a crack 1ft away from where the post is going to be mounted crack about 5ft long. It was caused by a dividing wall that was there.
Concrete is 10 year old

This is there one I was thinking

https://ige.ie/pacini-2-post-lift-4000kg-heavy-duty/

dar_cool

Is it a big crack ? Id be nervous enough around cracks. Im sure the lift company could advise better. That lift looks the job, electronic safety locks are much better than manual ones and that lift has electronic locks. They are handy enough to install if you have proper drill and few mates to lift the posts as they are bloody heavy!!!
I got a 2nd hand 4 tonne lift off a mate who was moving house for 500 quid. Hasnt missed a beat. Thoughts of crawling under a car now makes my skin crawl ðŸ˜

Passataudi

dar_cool wrote: »

Is it a big crack ? Id be nervous enough around cracks. Im sure the lift company could advise better. That lift looks the job, electronic safety locks are much better than manual ones and that lift has electronic locks. They are handy enough to install if you have proper drill and few mates to lift the posts as they are bloody heavy!!!
I got a 2nd hand 4 tonne lift off a mate who was moving house for 500 quid. Hasnt missed a beat. Thoughts of crawling under a car now makes my skin crawl ðŸ˜

Crack is not that that big just long approx 5 ft. I was going to go originally with a 2 post without H support frame but 5 inch was not enough and with crack be safer but maybe I will have to get it fixed as I would not feel 100% under knowing about the crack. I'll only ever be putting cars on it or biggest caddy van as roof is to low for anything more

Was looking for second hand lifts but all I could see is some that have mental work done or some maybe 5 or 6 year old with plenty work with asking prices of cheap new lift

Passataudi

Hi all, just power washed floor couple days ago getting ready to paint it and as all ground in dirt was gone there an awful lot cracks in floor around lift posts. Also my lift has the H frame suitable for floors with less concrete

mickdw

If you think there is deterioration in the floor since installing the lift, you need to stop using it and have it checked and likely reinforced.
Its not something to be messed with.
Realistically, assuming reasonably compacted sub structure, its not going to move too far but depending on how the lift is put together, a small movement could cause a failure of the lift.
You may end up redoing a portion of the floor in the lift area.

Still waters

Better safe than sorry, get someone that knows what they're doing and get them to make good the area needed for the lifts

Passataudi

Still waters wrote: »

Better safe than sorry, get someone that knows what they're doing and get them to make good the area needed for the lifts

Yes im going contacting the people who installed it and get them to take a look.

mickdw

Id imagine if they are in any way professional and considering they dont know what the concrete is like, they can only suggest that you need to improve floor.

Passataudi

mickdw wrote: »

Id imagine if they are in any way professional and considering they dont know what the concrete is like, they can only suggest that you need to improve floor.

My taughts even if it was safe looking at big car up in air then looking down at the 2 small posts compared to car im going to dig out floor and put good stuff in to it. Better safe than sorry or thinking about it

mickdw

Ya.
Personally, Id dig out the area of the entire lift plus say 1m all around, compact a good hardcore base and pour 6 inch floor with further thickenings to 8 inches around edge or at any possible support points.

mk7r

mickdw wrote: »

Ya.
Personally, Id dig out the area of the entire lift plus say 1m all around, compact a good hardcore base and pour 6 inch floor with further thickenings to 8 inches around edge or at any possible support points.

If going to just add in a patch I'd say 12 inches minimum 1x1m around each leg and tie in with rebar drilled into existing base.
I just put in a new lift OP and the min recommend was 6 inch 3000 psi with steel reinforcement, 4 inches for me is just too little, especially if you don't know the strength of the mix

Passataudi

mk7r wrote: »

If going to just add in a patch I'd say 12 inches minimum 1x1m around each leg and tie in with rebar drilled into existing base.
I just put in a new lift OP and the min recommend was 6 inch 3000 psi with steel reinforcement, 4 inches for me is just too little, especially if you don't know the strength of the mix

Lift people said with H frame is min 4 inch for good concrete but by finding all cracks in concrete im going to pull it up. Im not a garage just hobby but expensive hobby. But we all have our own interests.

Passataudi

Some garages sees 10 and more cars a day on lift. I see 2 a month basically

mk7r

It makes no difference how often it's used though, it's either strong enough or its not, even if only used a few times a year

MercMad

When building my garage I had hard-core, then 6 inches of concrete reinforced with steel mesh. Best to be safe than sorry.

galwaytt

225mm 30N concrete here reinforced with A193 mesh.

lomb

Do I put the rebar or mesh deep or shallow, Im doing one at moment. Is the rebar below or above surface of the expansion bolts. Normally rebar would be put near surface but Ive read some lift manuals and they advise not to use it others advise using it deep?

Very confusing

mickdw

Concrete without reinforcement only has strength in compression. Basically you cannot squash concrete but you could pull it apart with little structural force.

Adding the reinforcement adds strength in tension too.

Taking a beam supported at either end. This will be likely to sag in middle. Basically trying to compact at top and pull apart at the bottom so steel would go at bottom (in most simple terms)

A cantilever beam (one where it is not supported at the end and has an overhanging section) will be likely to drop at the free end, pulling apart along the top surface. This will need reinforcement at top of concrete.

Taking this basic idea to your slab, I would reinforce at bottom unless your loading point onto the slab was near an edge of the slab.

In that case, I'd reinforce top and bottom.

monseiur

I would concur with what mickdw advised. Also if you are just reinforcing the concrete slab under lift and not the whole garage floor I would recommend the slab to be 900mm all around bigger that the actual footprint of the lift. Say the footprint of lift is 2m wide x 3m long then the reinforced slab should be 3.800m wide x 4.800m long x 200mm thick. With a thick slab and the steel reinforcement say 140mm from the top it's less likely that you'll hit steel when drilling for lifts anchor bolts, unless of course you plan to place bolts in conctere before it sets.

lomb

https://www.boards.ie/discussion/comment/119320298#Comment_119320298

Thanks Mickdw, I shall reinforce the slab on the bottom, and where the lift posts are the top also even though they wont be at the edge of the slab as Im putting it in the middle as I cant be dealing with digging it up if I see cracks later. If it cracks well at least theres 10mm mesh in it so cant really pull apart. Il use 10mm mesh under the lift or would you use high tensile rebar or would I be ok with lighter mesh 6mm at the base of the slab?

The slab will be 6x10m floating and the base seems to be an old compacted stone type driveway with the look of tarmac. As its been there so long and Im using 225mm thick of high strength c35 concrete do you think that will be ok without digging up and putting down hardcore? Theres no trees around

So Im thinking wire mesh on bottom of slab and wire mesh on top where the lift is located and at ramp entry point where cars will drive on to reinforce the slab edge and somehow tie these together

Im building a galvanised metal shed over so fairly lightweight

With regards avoiding drilling the mesh or rebar Im thinking the bottom will be clear of the expansion bolts the top I could mark on the timbers and then onto the set slab prior to removal the mesh locations and as these are regular can figure it out later.

blackbox

Have you considered a scissor lift?

lomb

https://www.boards.ie/discussion/comment/119338416#Comment_119338416

sure, but need storage of car under

lomb

Would for a

6x10m floating slab with no excavation placed over compacted tarmac and a dpc membrane for a galvanised garage workshop

would a box section on the perimeter made of 12mm rebar

Rebar Reinforced Steel Bar 12mmx6m (5.32Kg Per Bar) (mcmahons.ie)

and then thin 6mm mesh on the entire base suspended off the floor of the slab

Reinforcing Mesh | MD O'Shea & Sons | Cork | Kerry (mdoshea.ie)

and then say 1x 10mm mesh sheet under the two post lift

Standard Reinforcing Mesh | A393 | 4.8m X 2.4m | 10mm (mdoshea.ie)

on the top of the slab walked in by me to be within the slab (this allows wellington boots on ground easily through the pour)

be ok?

Would anyone step up the rebar (to 16mm?) or mesh sizes especially on the base of slab under lift (swap one sheet of 6mm for 10?), and how often to support the mesh on the floor off the dpc to stop it sagging when wellington boots are walked upon it?

Anyone advise a length of rebar tied to the thin flimsy floor mesh to reinforce the concrete under the lifts?

My goal is A not to have cracks, B if there are cracks ignore them and C not to have the slab split and crack excessively at least.

On a 6x10 slab should I pour it in 2 or can I get away with surface cuts into the concrete 1.5 inches like they do in the States in a cross pattern

Il be using C35 concrete lightly vibrated and 225mm deep forms

Thanks for all help!

blackbox

https://www.boards.ie/discussion/comment/119338744#Comment_119338744

I store a car over my scissor lift. Are you planning to double deck them?

PS my scissor lift is only "mid rise" but has been good for all jobs so far.

lomb

https://www.boards.ie/discussion/comment/119340385#Comment_119340385

Double deck for storage yes. I kind of had my heart set on a Twin Busch two post ,the scissors are also class though it has to be said

https://www.youtube.com/watch?v=FE6Zv5G07jI

lomb

Il crack on with what's there, I might run a length of 16mm rebar the full 10 m length in the center tied to the base mesh as I don't want her to sink like the Titanic in two! Sink as one piece..

really looking forward!