Topic: Leveling Garage Floor

My shop floor is very uneven and I am looking for some ways to level it out.  As it stands there is upwards of -4in of deviation from the maximum height.  With an average of of -2in from the peak.  Integrating the deviations shows that I will need around 3yards of material to level it.

What are people's ideas on how to level it out?

Remove and re-pour?
Clean, roughen, and pour over top?
Commercial leveling product?
Some kind of concrete jacking system?

Moot Point Racing - 1991 Volvo 240

Re: Leveling Garage Floor

Here's a website that you may find your answer at: http://www.garagejournal.com/forum/
Search there or sign up and post the question.

3 (edited by OnkelUdo 2016-11-16 05:58 PM)

Re: Leveling Garage Floor

More the question is what is your goal with having a level floor?

Stop tools from running to the NE corner when dropped?
Keep the spilled fluids from creating a river and form a lake instead?
OCD?
Some valid reason I really can't think of?

Now if it is cracked, uneven, spawled, etc...I get it.

FYI, by code, most garages built now slope to the door(s).  Minimum slope can even be listed as 1/8" in some jurisdictions.

Re: Leveling Garage Floor

Mike's right. By code most places will require that the floor slopes to the door. Yours however sounds like it has settled after it was poured as even concrete will level out somewhat, or at least more so then what your floors sounds like.

There is one solution if your floor is a floating floor, that is it's not attached to a house or the floor was poured after the walls were built.
It's called 'Mud Jacking".  It where holes are drilled in the floor and a cement like slurry is injected under the floor under pressure. It will raise the low spots for sure and get you close to level. I had this done to my patio some years ago. It can be done even if the floor is cracked but works best if the floor is one piece.

Re: Leveling Garage Floor

So let me clarify a few things.

First, the floor is not sloped in any one direction it is cracked and uneven.  The reason I want to level is is that, putting a car on jackstands can be precarious because they are never the same height and often it is hard to find a spot where the jack stand sits securely.  Also  tables don't sit  level because it is much higher near the edges. It is also very hard to roll things around. 

Second, the shop is in a barn that was built pre 1920 they used to build custom carriages in it and then it was a dealer for Moon Motor Cars.  Anyway the result is that the slab probably does not conform to any standards .  For instance there is not a concrete sill along the edge.  The slab was poured flat and then the sill is made out of wood. 

I think mud-jacking might be the way to go.  I think they also do it with foam nowadays too.

Moot Point Racing - 1991 Volvo 240

Re: Leveling Garage Floor

With that description...if it looks like I expect...you probably need to rip out and replace.  Part of your issues will be age and inadequate reinforcement and/or depth but I would bet a c-note it is mostly improper prep with a dash of drainage issue if your soil is even slightly expansive (usually clay).

So if you want to verify, drill some test holes with a hammer drill.  Check concrete depth (probably rat-slab 2-3").  Then stick a piece of rigid tube in and pull out a 3" deep sample.  It will be dirt and likely either lots of organic material in it (settling) or clay (jacking).

If I am right, you want a pro or gifted amateur to assess what you need.  With organic, uncompacted soil you usually scrape off 6", put in compacted gravel.  For clay..it gets more critical to avoid drainage issues from the garage and for about 10' feet minimum around it...then do a decoupling membrane and sand.

All that said...want a redneck fix?  Knock out the high spots and re-pour those.  Drop in 6 x 6 mesh and poor a 3" rat slab right on top.  Bonus if you rent a concrete nailer (Ramset, Hilti, etc) that can shoot either studs or forming nails in the existing slab, tie the 6 x 6 to that elevated at least a 3/4" off the old slab.

Re: Leveling Garage Floor

I'm not sure on the material, but I do not think that it is clay.  Organic seams likely because if I had to bet it was a dirt floor and then they poured on top of that after the barn was built.  I think the verdict is to leave it to the professionals, and it sounds like at least a $10k job. 

Your redneck fix sounds tempting, but it does not sound like a project I want to undertake. I have a few race cars to build.

Moot Point Racing - 1991 Volvo 240

Re: Leveling Garage Floor

Got to be sure foundation is nice and solid. Otherwise what ever you gona build on top wont last.
lazy me is going for self leveling concrete. My want to put some mud of regular concrete in the lowest area. then make a form and pour out self leveling, just do math so you use just the right amount. adding reinforcement is a big bonus like rebar or mesh.

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Re: Leveling Garage Floor

kakarot1232001 wrote:

Got to be sure foundation is nice and solid. Otherwise what ever you gona build on top wont last.
lazy me is going for self leveling concrete. My want to put some mud of regular concrete in the lowest area. then make a form and pour out self leveling, just do math so you use just the right amount. adding reinforcement is a big bonus like rebar or mesh.

I have a plan for that.  I think I am going to make a massive jig to hold the project car nice and level.

Moot Point Racing - 1991 Volvo 240

Re: Leveling Garage Floor

Seems like quality screwjack type jackstands might work as a stopgap

1990 RX7 "Mazdarita" 
1994 Jaguar XJ12 (Winner C-Class 2013 Sears Pointless)
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1980 Rover SD1 (I Got Screwed 2014 Return of Lemonites) (Sold -> Houston.  Gone and forgotten)

Re: Leveling Garage Floor

One corner of my 40x22 garage was sunk about 6 inches due to poor alley water drainage.

Had a teammate of mine jack that corner up, remove the broken/sunk pieces, and repour the leveled corner, and set the garage back down. 90 bags of concrete to give you an idea... Roughly a 6x10 area?

Anyways, it's a 100 year old garage,we used car jacks and screw posts to lift/support it, there were lots of creaks and pops from the structure, but for about $1800 in materials and 3 days of labor... it should last at least 10 years, and was much more DIY friendly than I expected it to be. Can take pictures and elaborate if you're interested.

"THE WONDERMENT CONSORTIUM"
Nothing's for certain, it could always go wrong. Come in when it's raining, go on out when it's gone.

Re: Leveling Garage Floor

We have jacked more than one house up to re-pour perimeter foundation walls (crawlspace on footer...above grade was two wythe brick).  Jacking is nerve racking even with the right equipment until you have done it a few times.

Sounds like the OP's barn is probably a mortared ruble perimeter foundation with a poured rat slab since he mentions there is no concrete sill (not definitive).  My 1930's garage is a stacked brick footer one brick extended above grade with a poured rat slab.  Our water table is high and the garage sits basically on beach sand...oddly, has not move much in the past 3/4 century.