Garage foundation depth?

[Z71Gladiator]

Planning to add on an attached garage and using cinder blocks block for the outline and eventually pouring concrete in the center, not really sure what kind of foundation this is called but I have seen it done before.

Anyone know what depth below grade I would have to go to make it secure or what the minimum required is in south dakota? Thanks in advance.

 

[LB-1911]

A good place to start might be -

http://www.rcgov.org/Growth-Management/building-permits-inspection.html

http://www.reedconstructiondata.com/building-codes/south-dakota/rapid-city

 

[Stuart in MN]

The frost line appears to be 42", so you need to be below that: http://www.amlegal.com/nxt/gateway.dll/South%20Dakota/rapidcity_sd/title15buildingsandconstruction/chapter1513internationalresidentialcode?f=templates$fn=default.htm$3.0$vid=amlegal:rapidcity_sd$anc=JD_15.13.270

(in that link, look for TABLE 100-B CLIMATIC AND GEOGRAPHIC DESIGN CRITERIA, you may have to scroll up a little bit.)

 

[Xray Dave]

When I was living in NH many years ago the foundation footings had to be a couple feet below the frost line/depth. So check with your local building commission/department. In Russia I understand that they excavate for footings then leave it "open" to the elements for a year or more. ???

 

[Z71Gladiator]

Thanks everyone. I think im going to take your advice and talk to the building official on tuesday and see how far below the frost line I have to be for sure.