Garage Concrete Floor Slab

[cheddar 86]

Anyone have a ballpark idea of what it would cost to have a concrete garage floor slab replaced? Apparently the geniuses that owned our place never hosed salt down after the winter, and I think they may have practiced the keg toss (like on strongest man competition) on it.

Average size two car garage...just looking for rough numbers - I don't want to contact any businesses to get a quote because they seem to think that means I'm seriously considering doing it right away.

Thanks

[MinnesotaMike]

I have the same problem, very pitted where the tires sit in the garage. I heard about a company that resurfaces the slab without replacement. They beat it up with steel bearings or something and resurface.

Sorry, I don't recall their name.

Good Luck,

Mike

[BoxMN]

I am not a concrete guy, my cousin does it for me. But I think a ballpark range could be in the $4-$7 per square foot arena. The low might be if it is all prepped and ready, and the high might include removing the existing and then putting in new. You would have to figure prolly about $350-$400 for a dumpster too. Those are just guesses though, based on old quotes I got several years ago, and bit increase for COGs. Good luck!

[trolloni]

wow 7 bucks a square ft !ive been doin somethin wrong,

[BoxMN]

wow 7 bucks a square ft !ive been doin somethin wrong,

Umm, what does that mean? Is that cheap or expensive? He charged me only material and time for his guys so was pretty cheap for me, but he said that is the general range of what he quotes depending on the job, but did include site prep (skidloader) prep and fill and steel. So like I said, I am only guessing, but it seems somebody here might have more than a guess like me And the OP's job is kinda unique in that he has to remove the old slab too...

Good luck.

[DRH1175]

There are many resurfacing products out there. And a few companies that will do it. Unless the entire slab is breaking up. All you need is it to be resurfaced. That would be way cheaper than complete replacement. And sealed to keep the salt etc from getting back in.

I hear your pain though. My back garage, when poured by previous owner was never jointed so I have cracks running all different directions from the frost. Not to mention they put it in the lowest place in the yard so in spring thaw it is under 2 to 4 inches of water before the frost comes out.

[JohnMickish]

For about $500 a guy can cover the whole floor with those hard plastic interlocking tiles that are made for a garage. They come in lots of colors too.

[cheddar 86]

I should've posted a picture of the floor so people could wince and say....ouch that's way worse that I imagined - there are tons of deep craters (somewhere in between the size of a baseball and softball), including a bunch of crumbling near the driveway. I appreciate the mentions of resurfacing but it's way past that point. Problem is if I get it fixed it has to be just for my "enjoyment" because no way I'm gonna add value to the house with a normal looking garage floor.

[trolloni]

Box ,i am a concrete contractor since 1976 and its tough to get 3 bucks in this current time of economic boon! Chedder is it a floating slab or sitting on a foundation? do you have a drain?is it sloped? or is it flat?if its a floating slab they will have to saw around the perimeter ,[more cost 5.50- 8.00 lineal foot] if its a foundation they can just hammer the thing out be careful it might be tied to the wall or sitting on a ledge.once you have it openened up make sure the fill underneath is not sunkin or wet, if it is address it [more cost for the labor, fill ,compacting] is it 4, 5,or 6 inches thick?any codes or permits needed?does it have rebar ,mesh or fiber mesh in it? the root of youre problem sounds like it was placed too late in the year and probably froze after they poured it either that they drove on it to soon before it was cured[28 days for concrete to get 90% strength] and when they did the vehicle had salt on it ate it up! one other thing may have caused this they poured it in summer and it set up fast and they threw water on it to be able to finish it. this is why i try to sell people sealer on all concrete it gives you some protection against salt oils the worst part nowadays concrete is full of admixtures that allow em to pull cement powder out of the mix .its not all cement like it used to be !sealer will help overcome that problem .now this is out of the way i say forget patching it [never lasts]youre floor is deteriorating and will continue to do so,tear out and repour is youre fix ,call around and get some ideas from youre local contractors they can help,[its what they do] make sure they have been around for awhile .but if you want cheap then get some scabs to do but once again youll be stuck with what ya got just like now !

[cheddar 86]

I don't know if it's floating or not. What should I look for to find out? No drain, to the best of my knowledge no slope. Not sure about thickness. Most likely need permit, don't see any rebar/mesh or fiber atleast where I have craters.

[1johntimm]

Is there a coarse of block around the edge? Do the block go into the ground or are they just on top of the slab?

[cheddar 86]

I'll have to get back to you on that one I can't picture it in my head (what it looks like).

[BoxMN]

In general, if it is attached it is usually not floating, and if detatched it is usually floating, unless very large, isn't it? Again, just guessing based on my limited knowledge.

Trolloni, thanks for giving that info, that helps me to understand better, I always try to learn a bit, even though I don't do it myself. FWIW - my cousin used to be bricklayer then turned fireman, now the concrete is his second business. Been doing it as a business for about 20-25 years, and I know from watching the serious concrete guys (like you and him) that have the right equipment and knowledge, that I will never do concrete myself, there is a lot to it if you want it done right, including the proper equipment. BTW - since his concrete is not only job, he can pick and choose a bit more the jobs he wants, as he has other income. but not sure what his cost is nowadays. I know my 1000' garage and 36'x50' driveway is a beautiful sight I love concrete.

edit - cheddar, if it is not floating, when you pour it again, I would recommend doing a gentle slope towards the doors. Water will flow out gently, and works really good for me, when you don't have a drain. Even in winter, especially if it ia attached or you heat it, snow and slush goes right out or is easily "Helped" out more than flat. Good luck.

[cavalierowner]

I can't respond about cost. I would suggest contacting 3 concrete contractors for that. And remember that the cheapest price is not always the cheapest price if things go wrong. Ask for and check references; do some research on the contractors.

I can talk about what you have. In addition to not maintaining the slab by previous owners, that kind of damage can also be caused by an inferior concrete mix or an inexperienced concrete finisher overworking the slab during finishing. If you decide to have a new slab put in, I would suggest telling the contractor what mix design you want and ask for the mix design documentation from the ready-mix plant. For a good, weather resistant slab, I always specified a minimum 4,000 psi mix, air entrained, minimum 540# cement per CY, and maximum 4" slump; and don't let them add water at the site. Then, as others have said, put on a good quality sealer.

[tyrant]

In Bismarck I was quoted 3K to replace my drive way if I demo the old concrete.

Two car driveway very close to the same size as my garage.

[boatfixer]

Its perfectly permissable to add water on site if allowable. By that I mean all mix designs have specified cement to water ratio,(usually in the .4-.5 range) not are all the same. We allow the aggregate moisture to determine how much water is to be held or added during batching, depending on moisture readings and also on the mix design. If the design allows for "X" gallons per cement weight and we hold some back, that water maybe added back in and may not sacrifice or be detrimental to strength whatsoever. Its nearly impossible leaving the plant with a typical 4000 psi (for instance) at a 4" slump and still having that upon site arrival, of course time has a lot to do with it as well as admixtures, temperature, humidity, flyash etc. Personally I like to roll out of the plant slightly tighter than spec, drier mixes tend to aggitate more consistantly, less tendancy for caking.

We prefer the use of midrange water reducers or plastisizers if a contractor has a situation where a less viscous mix is desirable. Also, our mixes are designed around end strength and we dont pull powder because admixtures, not sure of what admixture we would have that would do that.

[cavalierowner]

Yep, I don't have a problem with adding water on site as you are describing boatfixer. What I DO have a problem with are the few contractors who don't like working with a stiffer mix and start adding water until they get a slump as much as twice what was specified. I have seen that almost exclusively in residential work because we generally don't require a lot of testing. In commercial work we always require testing, including slump tests, so the contractor seldom will chance doing something that could compromise the mix design or concrete durability. So the general rule I use is don't add water at site; if you want to do so, tell me why and show me it will still meet spec.

[boatfixer]

I agree and will add that we don't add unless requested, then documented and signed.