How much to build a 20x20 foundation for a garage?

Discussion in 'The BS Topic' started by Chevy 350, Nov 4, 2010.

  1. Chevy 350

    Chevy 350 Veteran Member Lifetime Gold Member

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    Apr 4, 2007
    So. IL
    I have a 20x20 shed next to my house from the turn of the century. There are still ceramic knobs inside but not wired up anymore. Its rotten and ready to be torn down.
    I saw an ad for a 20x20 steel garage for $3535 in the southern illinois trader. Called and the guy said with 5% discount right now through the factory and sales tax it would be like $3601 installed. This comes with an 8x8 garage door, walk in door, and a window
    Framing is 2 1/2 x 2 1/2 14ga steel square tubing I think he said and it installs in less than a day
    Thats all fine and dandy but if Iget one I want a concrete floor. Right now its dirt. Im trying to get some idea what it would cost for me to have a 20x20 foundation built for this garage

    I was told to have rock packed down and leveled with one foot footings around the whole outside and to go atleast a foot down with the footing.I want 4 inch thick floor. I have no idea how much this will cost but I was told its very expensive
     
  2. vfw_1168

    vfw_1168 Veteran Member Lifetime Gold Member

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    May 3, 2010
    wheelersburg,ohio
    yes it is costly .... call around and get eastments ... if you dont know how to do it your self ... the footer is easy part it is floating the floor and figuring out how many yards you need
     
  3. Chevy 350

    Chevy 350 Veteran Member Lifetime Gold Member

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    Apr 4, 2007
    So. IL
    Guys at work keep telling me to get a portable building but they just seem kinda junky
     
  4. vfw_1168

    vfw_1168 Veteran Member Lifetime Gold Member

    1,212
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    May 3, 2010
    wheelersburg,ohio
    yea i know what you mean on that.... i would rather have a pole barn type any day.... my best guess is you will have about 10 to15k in the whole thing.... that is on the high end
     
  5. Chevy 350

    Chevy 350 Veteran Member Lifetime Gold Member

    484
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    Apr 4, 2007
    So. IL
  6. Gary S

    Gary S Administrator Lifetime Gold Member

    A wild guess would be that you need around 8 yards of concrete. Depending on what price you can get on the concrete, the cost can go either way. Let's assume $100 a yard so now you have $800. If you do the pour yourself, you can frame it and pour it for under $1000. If you hire someone to do it, expect to pay twice that if your site is already level. To pour a foundation for a building, you need to at a minimum dig around the perimeter for a thickened edge. Any extra excavating or leveling or fill probably would be added.

    I poured my 24x48 slab for my garage for under $3000, and put a stick built building on top of it. The final cost for the building and foundation for my 1152 sq ft garage ran around $12k. Then I put more money into insulating, wiring, and finishing the interior. But, I did all the work myself.
     
    Last edited: Nov 4, 2010
  7. At Home Camaro

    At Home Camaro Veteran Member Lifetime Gold Member

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    Mar 13, 2002
    Md
    I would think code for you footings would be deeper than 1 foot. In Maryland they are 30" if I remember right. Need to be below the 100 yr frost line.

    The above comment would be important if you are getting a permit.
     
  8. Chevy 350

    Chevy 350 Veteran Member Lifetime Gold Member

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    Apr 4, 2007
    So. IL
    I figured if I [ut the garage right where the old one is they wont even know I tore the old one down and put a new one up
    Is 12" good enough to actually work or do I actually need a really deep footing?
     
  9. mjoc

    mjoc Veteran Member

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    Apr 29, 2003
    Sherman Oaks, Ca
    In Los Angelos california. you need to go at least 18". Also don't forget the cost of rebar. You will probably want a sink so you need sewer and water supply. A nice drain in the middle of the floor is nice too. easy clean up.


    Mike
     
  10. Gary S

    Gary S Administrator Lifetime Gold Member

    Check your local codes. That will tell you how deep you need to go. Around here, a building that has water in it needs 4 foot footings. A building with no water meets code with 12" footings.
    And, we get to -45 degrees here in winter, so all this talk of frost line isn't as important as people think.
    Check your local codes.
     

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