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Thread: My Building Code and Concrete slab??

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    SNOW JW is offline Junior Member
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    Default My Building Code and Concrete slab??

    Ok so things are getting more sticky on the codes and they are now sending inspectors within 1 mile of town so if say I was to build more units what can I get ready for as far as what specs will be needed for the foundation-slab. I don't want to go into it with a bid then get a pour done and find out it's not up to spec because my Sub was out to lunch and did not know the codes.


    Below are the codes the city has adopted. I will get the book on the way but curious if anyone knows off-hand what is needed.

    2009 International Building Code
    2009 International Residential Code
    • 30 lb Ground Snow Load
    • 90 mph Wind Load
    • Exposure C
    • Seismic - 0
    • Frost Depth - 48 inches

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    SMSSId's Avatar
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    Default Re: My Building Code and Concrete slab??

    I think you will find maybe not all, but most inspectors do not know all the codes and are not necessarily willing to vary from what they know. Some communities go so far as to ADD some of their own code requirements.

    The big red flag I see is the 48" frost depth. It shouldn't be an issue with a floating slab and/or monolithic pore; however, most inspectors and many concrete subs are not familiar with this type of construction. I can hear them now; you need to have your footers below frost line. Not So. We run into this issue with every building we’ve put up. Spend the time and money to hire a structural engineer that KNOWs what a floating slab is. The money saved in concrete should more than pay the engineers fees. Whoever you’re purchasing your building from can often recommend an engineer licensed in your state that’s familiar with floating slabs. With the engineers seal on the plans, it makes a big difference in how the local inspector interprets what is going on.

    Best of luck
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    SNOW JW is offline Junior Member
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    Default Re: My Building Code and Concrete slab??

    Thanks for the reply.

    The floating slab is a gray area I agree I would much rather not do footers. When talking to the city they said "Just keep it in the context of the code and you will be fine" it's almost like they have not a clue what to say either so to keep liablity off them they just sidestep the ??

    Sure that's all fine and dandy till I have $6 per sq foot in mud on the ground and my luck I get a PITA inspector. I don't think it will be an issue but I am a worry worm when it comes to these things.

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    Steve_hajewski is offline Senior Member
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    Default Re: My Building Code and Concrete slab??

    I'm a marketing guy not an engineer by any means, but I would suggest that you should get in contact with your building supplier to figure this out. We provide foundation plans for all of our buildings which are designed by our engineers who are licensed to figure this out. The plans account for various loads and are adjusted based on many factors including what codes your area follows.

    Your local (and I believe in most of not all areas) state inspectors will need to review the engineer's plans in order for you to get building permits. Feel free to contact one of our regional managers to find out what the process is for your state. 800-356-5824. Just ask the receptionist for the regional manager for the state where you wish to build.

    I think that floating slab works for our basic one story buildings in most places unless you are heating it.

    Steve Hajewski
    Marketing Manager
    Trachte Building Systems
    www.trachte.com

    Quote Originally Posted by SNOW JW View Post
    Thanks for the reply.

    The floating slab is a gray area I agree I would much rather not do footers. When talking to the city they said "Just keep it in the context of the code and you will be fine" it's almost like they have not a clue what to say either so to keep liablity off them they just sidestep the ??

    Sure that's all fine and dandy till I have $6 per sq foot in mud on the ground and my luck I get a PITA inspector. I don't think it will be an issue but I am a worry worm when it comes to these things.

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    SMSSId's Avatar
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    Default Re: My Building Code and Concrete slab??

    If you’re not sure about floating slabs here is a detail of what we use in our area. However, our frost line is only 24"
    Concrete_Slab.jpg
    Also as Steve_hajewski posted, check with your building supplier, not just a contractor, inspector or installer.

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    Louis Gilmore is offline Junior Member
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    Default Re: My Building Code and Concrete slab??

    The 2009 IBC will not allow for a floating slab in a zone that requires a 48" frost line footing, for a heated or unheated "self storage" building. Call Miller Buildings 800 323 6464 X104 ask for Louis Gilmore. www.MillerBldgs.com

    P5180739.jpg
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    SMSSId's Avatar
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    Default Re: My Building Code and Concrete slab??

    Quote Originally Posted by Louis Gilmore View Post
    The 2009 IBC will not allow for a floating slab in a zone that requires a 48" frost line footing, for a heated or unheated "self storage" building. Call Miller Buildings 800 323 6464 X104 ask for Louis Gilmore. www.MillerBldgs.com

    P5180739.jpg
    Wow! Code never ceases to amaze me.

    When the ground freezes, it’s no different than water, it expands (frost heaves). Maybe someone would be so kind as to explain:

    If you build an unheated building and your concrete footers are below the frost line that means the footer will not be affected by the ground freezing. However, what is going to keep the floor slab from being affected by the frost heaves in the other parts of the building that are not below the frost line?

    Thank Louis for the heads up, you got me back to doing some code catch-up.

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    MZC&D is offline Senior Member
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    Default Re: My Building Code and Concrete slab??

    I had never heard of using a floating slab on anything structural befor, but if they will allow it and it works I can see the cost savings in concrete alone. The only floating slabs I have know to be used were no structural such as floors in a pole barn or a patio.

    As for why the ground doesn't heave in the middle of a slab with or without footers, from my understanding the slab somewhat protects the ground from the frost there, and is somewhat of an insulator for the ground.

    Now my questions is with a storage building on a floating slab, do you have any problems with it heaving, or does the whole slup move up and down? I don't have any experiance with floating slabs, all the years I was in construction( mostly metal buildings and storage facilities) we always had footers in everything we poured or built.

 

 
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