(new garage & pouring floor) need concrete specs for 2 post lift?
04-12-2009, 08:26 PM
#1
(new garage & pouring floor) need concrete specs for 2 post lift? 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?
What size area around the posts?
04-12-2009, 09:15 PM
#2
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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.
04-12-2009, 09:43 PM
#3
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.
When you say "4" slump", what do you mean?
Thanks for the info in detail
04-12-2009, 09:59 PM
#4
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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.
04-12-2009, 10:03 PM
#5
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.
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.
Thanks
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04-14-2009, 07:48 PM
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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.
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.
04-20-2009, 07:53 PM
#12
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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.
post some pictures up once you get the slab poured and the framing started.
04-20-2009, 09:49 PM
#15
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 !!!
04-21-2009, 08:10 AM
#16
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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.
04-21-2009, 08:09 PM
#19
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
http://www.challengerlifts.com/VS10.shtml