What Foundation Is Required?

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Posted by: from Chelsea
11/26/2011 at 6:33:46 AM


We are planning to build a 20 x 24 detached garage with an 8/12 roof pitch to allow for attic storage. The site is flat but approximately 2 feet below the grade of the existing driveway so would need to be elevated to allow proper drainage. Our soil is clay and we live in Western Quebec

What would be the appropriate foundation? We have had conflicting recommendations from full foundation to just a slab. We would like to avoid the expense of a full foundation but do not want to compromise the quality of the structure.

Thank you,


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Date/Time11/26/2011 at 7:37:19 AM

Hi Karrie!

Well just a slab is not good enough and not up to the code so forget that right away. Best thing to do is contact your local building inspection office for what your requirements are. But you should be at least 4 feet into the ground on a pouring footing. Frost walls is what the term is. That is your best and permanent solution. Hope this helps.


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Date/Time3/6/2012 at 10:10:01 PM

Hello Karine,

What you are asking is verry technical. The best would be an engineer to answer but yes you can build a cement slab you would have to dig then installe a menbrane geotextile put 2 feet of 3/4" gravel, then 4" of blue styrofoam the steel reinforcement bars and a 4500 mpa. But doing all this some time it is cheaper to do it the old fation way but like I said before just asking an engineer and you would get the right answer.


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