Footings?

sandyman720

The construction office in my town says footings need to be 30". I dug the corners and from the top of my slab to the bottom of the concrete is 24". How do I go about adding to this to meet the code so I can build on this slab?

Thanks!

concretemasonry

What are you building? - Garage, house?

Excavate to the proper elevation. If not, you may have to fill for frost protection and end up changing some building elvations and/or details.

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Dick

Engineer, designer and consultant recently active domestically and internationally on construction and design in about 35 countries.

gregj

Looks like you didn't get much help on the DIY site.

You're on the right track now by ensuring that your addition has a good foundation. You're really not suppose to post here but since no one is helping you at the other site I'll recomend that you ask your building department if you can use a "Frost-Protected Shallow Foundation" (FPSF). Your foundation might work for that with the addition of some insulation. Google up "Frost-Protected Shallow Foundation" and you'll find lots of info.

However, it's really difficult to know whether an existing outdoor slab is adequate to build on unless you know the construction details of the slab - and 99.9% of the time (or more) they are not adequate to support walls and a roof. If you can find out exactly how your slab was built then discuss that with your building department to see if it's adequate for your addition with FPSF insulation added. If you can't get all the details on the slab then your best bet is probably to remove it and put in a foundation designed for your addition. You'll be putting a lot of money into this addition so don't take a risk on the foundation.