View Full Version : (new garage & pouring floor) need concrete specs for 2 post lift?


9t8z28
04-12-2009, 08:26 PM
I am building a garage and I want to install a 7K 2 post lift. I need to pour the floor but I am unsure what thickness and p.s.i. concrete I will need?

What size area around the posts?

vaticano
04-12-2009, 09:15 PM
A 4 inch slab will be sufficient. Most garages are 4", but you can go deeper if you like. Just thicken the areas under the posts to 8-12 inches deep, and 2 foot square, put 4, 4ft pieces of rebar, #4 should be fine, bend them a bit so they go down into the thickened areas. You want 2 each way centerd on the hole. A standard 6 sack 4000 psi mix will be fine. Just don't let whoever pours it, add to much water, it will weaken the concrete. You want a 4 inch slump. You should also put some wire mesh or rebar in the slab itself. This will hold it together when it cracks. Rebar is better but mesh is cheaper. If you use the mesh make sure to pull up so it is in the center of the slab. Also you will need to cut exspansion joints to control cracking and relieve the exspansive stresses. You should cut the joints so that you have 10'x10' sections. If you need more info let me know.

9t8z28
04-12-2009, 09:43 PM
A 4 inch slab will be sufficient. Most garages are 4", but you can go deeper if you like. Just thicken the areas under the posts to 8-12 inches deep, and 2 foot square, put 4, 4ft pieces of rebar, #4 should be fine, bend them a bit so they go down into the thickened areas. You want 2 each way centerd on the hole. A standard 6 sack 4000 psi mix will be fine. Just don't let whoever pours it, add to much water, it will weaken the concrete. You want a 4 inch slump. You should also put some wire mesh or rebar in the slab itself. This will hold it together when it cracks. Rebar is better but mesh is cheaper. If you use the mesh make sure to pull up so it is in the center of the slab. Also you will need to cut exspansion joints to control cracking and relieve the exspansive stresses. You should cut the joints so that you have 10'x10' sections. If you need more info let me know.

How deep should the rebar be if say I make the 2 foot square section under the posts 6" ?

When you say "4" slump", what do you mean?

Thanks for the info in detail

vaticano
04-12-2009, 09:59 PM
How deep should the rebar be if say I make the 2 foot square section under the posts 6" ?

When you say "4" slump", what do you mean?

Thanks for the info in detail

The rebar should be just above the bottom of the fasteners you are using to hold the lift posts. So if the fasteners are 4" into the floor, you want the rebar at 3" down.

Concrete is tested with a slump test. What this means is a tester will take a 1 foot cone and fill it with concrete, consolodate it with a rod by poking it, the cone is then removed and a measurement is taken from the from the top of the cone to the top of the concrete. That # in inches will be the slump. When you order it just tell the batch plant you want a 4 inch slump, then when the driver gets there tell him the same. They will get you close. Plus or minus an inch wont hurt, but I have seen people pour out concrete that flows like water. This is not good and will cause failure.

If you are doing this your self, make sure you have all the tools to finish it. Finishing is what you do to the surface to smooth it out.

9t8z28
04-12-2009, 10:03 PM
The rebar should be just above the bottom of the fasteners you are using to hold the lift posts. So if the fasteners are 4" into the floor, you want the rebar at 3" down.

Concrete is tested with a slump test. What this means is a tester will take a 1 foot cone and fill it with concrete, consolodate it with a rod by poking it, the cone is then removed and a measurement is taken from the from the top of the cone to the top of the concrete. That # in inches will be the slump. When you order it just tell the batch plant you want a 4 inch slump, then when the driver gets there tell him the same. They will get you close. Plus or minus an inch wont hurt, but I have seen people pour out concrete that flows like water. This is not good and will cause failure.

If you are doing this your self, make sure you have all the tools to finish it. Finishing is what you do to the surface to smooth it out.

Wow. Awesome info.

Thanks

01ssreda4
04-14-2009, 01:33 PM
wow i know who to ask advice from on my concrete project....

Bad Blue WS6
04-14-2009, 02:57 PM
that is some good stuff.

9t8z28
04-14-2009, 03:45 PM
What is the difference from pouring it in one shot (footer and floor) vs. pouring the footer, letting it dry and then pouring the floor?

Someone mentioned to me (mono-lithick).? What does this mean?

vaticano
04-14-2009, 07:48 PM
Monolithic is just as you explained, Pouring the 2 pieces as one.

A footing or footer is nothing more than a stable block for a wall to sit on. It will help to spread the weight of the wall over a larger area to prevent sinking, while stablizing the wall from falling over.

The wall will be centered on the footing with 1 foot of concrete on each side of the wall. So if you had an 8" thick wall the footing would be 2' 8" wide, for residential walls, 12" deep. This will vary depending the what the wall will be used for and it's size.

Pouring a footing and a wall at same time is very dificult for several reasons.

With a footing you have a solid surface to build the wall forms on.
Without the footing you would have suspend the wall forms in the air.

(Could you imagine the trouble you would have holding a 30' long 8' high wall of plywwod in the air. And that would be just 1 side. If this was a house you would have 4 of these all together.)

This does not provide for a stable form. the form can easily move laterally making it hard to keep it straight.

You have vibrate concrete to prevent large holes in a wall.
This vibration causes the concrete to flow or move very easily.

Doing this monlithic would cause most of the concrete to move from the wall and overflow out of the footing.

You could put a lid on the footing, but the lid would allow for alot of trapped air and prevent the footing from filling properly.

It is alot easier to pour these types of things in 2 pours.
There are a few exceptions to this, but not many.


If any of you guys have any questions feel free to ask. I will answer them the best I can.

Just a little extra info.
Here is the formula for figuring how much concrete you need to fill a space.

Legnth X Width X Height / 27 = Cubic Yards

That will be the # you need to order it from the batch plant.

9t8z28
04-14-2009, 08:46 PM
Once again, you have helped alot. I am trying to rap up the plans and get the ball moving.

Thanks

vaticano
04-14-2009, 09:02 PM
No problem.

SSJIMMY
04-20-2009, 07:53 PM
I think 4" is considered the minimum but I would say 6" shoud be the minimum but follow vaticano suggestions cause you cant have to much support for a lift.

post some pictures up once you get the slab poured and the framing started.

9t8z28
04-20-2009, 07:59 PM
I think 4" is considered the minimum but I would say 6" shoud be the minimum but follow vaticano suggestions cause you cant have to much support for a lift.

post some pictures up once you get the slab poured and the framing started.

I will. Hopefully it stops raining!

SSJIMMY
04-20-2009, 08:33 PM
Send some of that rain down here we could use it to get rid of some of the fires.

whats some of the specs on the shop your building.

9t8z28
04-20-2009, 09:49 PM
Send some of that rain down here we could use it to get rid of some of the fires.

whats some of the specs on the shop your building.

It was going to be 20 x 30 but that just wouldn't cut it. I have an Impala that is over 18 FOOT long and I wouldn't be able to manuver it around (on coasters) along with my Chevelle being in there. We are going to increase the length by 15' and that will be enough for all of my tool boxes and engine blocks. The ceiling is 16' in the center. Next week I am going on the road to go and pick up my 9K Rotary lift that I scored for $800 !!!

cresswellracing
04-21-2009, 08:10 AM
Nice price on the lift. I have seen 7K units for over $1400. Most of the 7K units I was looking at called for min of 4" 3000 PSI concrete. So I poured 6" in that area and dug 2 24" round by 36" deep pillars and poured them along with the floor. Now my lift posts will sit right on these pillars. Super easy to do when you have an auger on a skid loader. Do yourself a favor, coat the garage floor with some epoxy while it is still new. I did mine with epoxy-coat and it came out great.

Phil99vette
04-21-2009, 03:50 PM
4" with rebar is enough, 6" is what I did with rebar.

9t8z28
04-21-2009, 07:14 PM
4" with rebar is enough, 6" is what I did with rebar.

4" with a 9K lift?

Phil99vette
04-21-2009, 08:09 PM
I ordered a Challenger VS10 lift, its symetric and asymetric if needed. It requires a 4" slab with rebar, I chose to do 6". Its a 10k lift. Check out...
http://www.challengerlifts.com/VS10.shtml

Phil99vette
04-21-2009, 08:10 PM
The lift was 2600 installed, more than the greg smith but I'm still not sold on a the cheap lifts, lets face it.... If the lift comes down you could lose your life

as35thss
04-21-2009, 10:20 PM
Here is some pics of my garage I finished middle of last year. I found a Rotary lift, 9000 lb for $2200.00 installed. It is 23x40. I added it on the side of the house and attached it to the old garage. So it gives me about 6 car spaces, seven if one is on the lift. We went 8 inch down on 4 ft pads and reinforced with rebar.
Good luck with your garage. If you have any questions. I will be glad to help.

9t8z28
04-22-2009, 07:56 AM
Here is some pics of my garage I finished middle of last year. I found a Rotary lift, 9000 lb for $2200.00 installed. It is 23x40. I added it on the side of the house and attached it to the old garage. So it gives me about 6 car spaces, seven if one is on the lift. We went 8 inch down on 4 ft pads and reinforced with rebar.
Good luck with your garage. If you have any questions. I will be glad to help.

Thats one kickass garage!

as35thss
04-22-2009, 11:26 AM
THANKS 9t8z28. IT WAS ALOT OF WORK. BUT IT IS COMING TOGETHER. THE BEST THING I DID WAS PUT AC AND HEAT IN IT. I CAN US IT ALL YEAR ROUND.

HUNTER02SS
04-22-2009, 11:46 AM
On your slab, make sure you can a mixer truck to the foundation. If not you will have to have it "pumped" by a concrete pump. If this is the case, you need to make sure that you tell the concrete plant that you are pumping the concrete and that you will need a 2.5-3in. line pump mix. Depends on the size of the concrete hose the pumper will be using. Most likely 2.5in. It's a little easier to move around.:D

9t8z28
04-22-2009, 12:11 PM
On your slab, make sure you can a mixer truck to the foundation. If not you will have to have it "pumped" by a concrete pump. If this is the case, you need to make sure that you tell the concrete plant that you are pumping the concrete and that you will need a 2.5-3in. line pump mix. Depends on the size of the concrete hose the pumper will be using. Most likely 2.5in. It's a little easier to move around.:D

I am not sure that I understand your post. Can you revise it or explain it a little different?

landonew
04-22-2009, 03:45 PM
I am not sure that I understand your post. Can you revise it or explain it a little different?

He means that the location is accessable by a heavy cement truck.

If the truck can't reach the site, you will have to pump the cement to the site from an offsite location that is accessable.

ja_engineer
04-25-2009, 01:52 PM
You could also locate someone with a conveyor truck, instead of a pump. A lot of the time if you pump it you have to have it pretty thin (slump >6") and some people will just add more water and increase the w/c ratio which in turn ruins the compressive strength, instead of adding a superplastcizer. With a conveyor truck you can easily go 4"-6" slump. The other thing you want to look into is the amount of air entrained in the mixture as this greatly increases durability when subjected to freeze and thaw cycles. If you have any questions shoot me a PM.