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View Full Version : leveling compound on cracked garage floor?


Lars
05-05-2013, 08:28 PM
Bought my house about a year ago and the condition of the garage floor is driving me NUTS! I'd love to put down an epoxy over it, but it is very pitted and spalled. None of the cracks look structural, I think it's just 60 years of water freezing and thawing on top.

See pictures below.

Can I just clean it and put some leveling compound on this front half and then epoxy it? Back half was added much later btw.

94523

94524

JohnE
05-05-2013, 08:35 PM
Wish I could help. You need someone who really knows about this. I'm thinking jack hammer it all up and start over including a little digout of the soil below and filling with good gravel and compacting properly.

Cloaked
05-05-2013, 08:46 PM
Bought my house about a year ago and the condition of the garage floor is driving me NUTS! I'd love to put down an epoxy over it, but it is very pitted and spalled. None of the cracks look structural, I think it's just 60 years of water freezing and thawing on top.

See pictures below.

Can I just clean it and put some leveling compound on this front half and then epoxy it? Back half was added much later btw.

For what I would expect out of your request (a good long term fix), the answer is no.

That looks to be old concrete (relatively speaking) with freeze/thaw cycles, salt/brine from your location...

John has the best answer for best results. Anything else will be like a coat of Thompson's water seal <<SPIT>> on a wooden deck... It won't last long...

A small project like that is really not difficult as a DIY if you plan properly. The key to any and all concrete placement is reinforcement and control joints. I am not talking about wire mesh either.... That is even more useless than Thompson's water seal....

JohnE
05-05-2013, 09:43 PM
A small project like that is really not difficult as a DIY if you plan properly. The key to any and all concrete placement is reinforcement and control joints.

If concrete moves (and it almost always will) it will crack. My understanding is that you either need to keep it from moving or control where it cracks. The first part is almost impossible, so control and expansion joints need to be installed. On the floors I just poured, the installer placed 1/2" foam around the perimeter for expansion and cut control joints in with a diamond blade saw. My last house was done the same way, and it's amazing that the floor cracked within almost every saw cut. You could see it if you looked into the saw cut. (I never did get around to filling the saw cuts with silicone - hopefully I do on this one.)

Cloaked
05-05-2013, 09:52 PM
The key to any and all concrete placement is reinforcement and control joints..

........, so control and expansion joints need to be installed.

....control joints and expansion joints are two different applications.... both necessary for different uses....

SOunds like you had yours done correctly....

Control is the issue most lazy concrete finishers choose to ignore or skrimp on. Concrete will crack...

I could go on and on.... (civil engine-ear) :)

.

JohnE
05-05-2013, 10:11 PM
I do realize you have much more experience than I do in this. I was just trying to clear things up for OP. Expansion joints as name indicates allows for the entire floor to expand by creating a space for it to do so. Foam or some medium is placed around the perimeter where the floor abuts the walls. Otherwise it will crack upon expansion. Control joints (in the middle of the floor) create a weak spot such that when the floor does crack it does so in the controlled location.

Cloaked
05-05-2013, 10:38 PM
I do realize you have much more experience than I do in this. I was just trying to clear things up for OP. Expansion joints as name indicates allows for the entire floor to expand by creating a space for it to do so. Foam or some medium is placed around the perimeter where the floor abuts the walls. Otherwise it will crack upon expansion. Control joints (in the middle of the floor) create a weak spot such that when the floor does crack it does so in the controlled location.
That was not the point. I was agreeing with you.. :D You're on it....

I could say the same about electrical and your experience.. I know on and off with a light switch.... That's it... You're the electrical guy....

,

BrooksfamX2
05-05-2013, 11:38 PM
cover it with some garage matting or outdoor carpet?

Thrall
05-06-2013, 04:09 AM
Yeah drop in some of those rubber garage tiles.
Or pull it out and re pour.

Traxx822
05-06-2013, 07:48 AM
Break it with a sledge. Put in new wire mesh, rebuild up the settled stone, compact it. Run expansion joint around perimeter only. Fill it up with Crete. Joint the floor into 4 pieces. California finish it so it looks pretty. That is all you can do to that floor. Any bandaids will not solve this issue. Good luck

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half a can
05-06-2013, 06:24 PM
I do epoxy floors for a living. Everything said above is correct. Your concrete has failed due to a bigger issue than just freeze/thaw. It looks like you have either expansive soils, improper compaction, slab to thin, concrete mix improper...the list could go on and on. There is really nothing that will fix that other than to tear it out and start over. If you are looking for something cheap to make it look a little better I would recommend a good degreaser to get the oil and grease out of the slab and a cheap porch paint. You will still have problems with the concrete and coating, but it may look a little better for a few years at least.

88 PS190
05-06-2013, 06:46 PM
Agreed on porch paint, really its so cheap you can throw some more on it, skip the compounds, you might be able to level the broken concrete with a roller or compactor.

88 PS190
05-06-2013, 06:51 PM
Reminds me of another guy who wanted a level floor to work on his motorcycles, leveled up plywood sheeting, nailed it to the floor with a ramjet nailer, then followed up with those garage floor tiles glued down.

Pretty nice result, fairly inexpensive.

Lars
05-07-2013, 12:35 AM
Thanks for the advice everyone! Bummed I can't just level it, I like the idea of degreaser and then porch paint, this is a starter home after all and don't plan to be here forever.

Kyle
05-07-2013, 04:18 AM
Yeah drop in some of those rubber garage tiles.
Or pull it out and re pour.

If you paint it and it gets wet then it will be very slickery. Yes slickery.

Agree on tiles

madcityskier
05-07-2013, 09:31 AM
Also, porch paint will peel sooner rather than later where your tires go on it. If the concrete gets wet, expect it to peel, particularly if it's ground water coming up.

Thrall
05-08-2013, 02:17 AM
If you paint it and it gets wet then it will be very slickery. Yes slickery.

Agree on tiles

Yeah epoxied the floors in the garage and shop. Should see when the kids forget and come flyin in on their bikes when it's wet ! Usually pile up against the wall!
No paint gonna fix that floor.
Good point though. That floor is pretty cracked up. Might not bust out too bad with just a sledge

onewheat
05-08-2013, 03:55 AM
One of those big car-sized rubber mats or two if your garage is that deep. It won't be "slickery", it will look nice and you can take them with you when you go.

Traxx822
05-08-2013, 10:34 AM
Just bust it out. Sledge will break that up quick. Crete is cheap. Your foundation walls can act like the frame. Throw down a little stone where needed. Compact it down. Then fill it up with new Crete. No saw joints just joint it with a finishing joint. Expansion the edges, throw in some wire or rebar. You're talking one days work and around $500 and its done. Or spend half a day. And $100 and it last for a year. 0.02

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Big tic
05-08-2013, 06:12 PM
There is many different types of concrete cracks.

If cracks appear shortly after placement (12 hour to 36 hours) they are considered "drying cracks" (although concrete does not "dry" the hardening is a chemical reaction). This happens because the mix water is evaporating and hence creating less volume in the concrete creating cracks. These cracks are using only surface cracks and are using filled with paste during power troweling. They can reappear later but are only super fiscal and pose limited to no concern for epoxy or cement based topping coats.

If they appear 36 hours to 28 days later usually this is plastic shrinkage cracks (caused by chemical reaction in the concrete along with evaporation of mix water). Typically saw cuts are used to create a controlled and visually pleasing crack. (ensure saw cuts are 1/3 depth of slab). If you would rather not saw cut there are ways to reduce your risk of cracking for a typical garage floor (20X24). WET CURE, nothing is better for concrete then to be flooded and keep wet for at least 7 days. When we do bridge decks we wet cure until full design strength is reached (28 days to 56 days) same with ice rinks.

NOW what you are dealing with is not a concrete issue at all. Your sub base was not compacted correctly and you sir have sub base failure. Is this a big concern, short answer NO your house is not going to fall down (unless your footings move highly unlikely). If this was a warehouse with automated fork lifts then this would be a disaster.

Option one remove slab. My preferred method is to use a gas walk behind saw and cut the slab out by pieces. I just hate the jack hammer and the walk behind is very easy to use. Rental rates will dictate your method. Rent a large compactor and cycle 3 times between wet and dry compacting. Put down welded wire mess but also use pyramids or bricks to hold the mesh off the ground and in the middle of the slab. NOW for the trick. Call up your local Ready Mix supplier and ask for Self Consolidating concrete (I work for Lafarge and we offer a product called Agilia (R) youtube it pretty unreal stuff). Follow the directions and pour it. You will be very happy with the finished product.

Option 2 top the floor for levelness and then cover with rubber tiles, carpet, etc (I would stay away from any mortar based tiles as the floor is still going to move and the cracks will come though the tiles). The concrete will still crack and you have not solved the main issue but it is a very viable low cost low effort option.

Option 3 (Which one of my customers recently did) removed only the area that had sunken. Compacted the subbase, drilled dowels into the existing slab and used 14mm rebar tied together at 16 inches. He order 35mpa concrete with poly fiber and re poured area. Wet cured for 7 days. He then rented a floor grinder and smoother out the entire floor. Followed by decorative saw cutting and acid staining. Came out really nice. Only time will tell how long it lasts but for then next 10 years it will be great.

Once again consult your local concrete supplier. Ask what they suggest and

Eric