How big do the footings need to be

Old 05-16-04, 04:41 PM
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How big do the footings need to be

I am in the planning stages of building a small vacation cabin. Relative size is 20 x 30 slab. One story with a mainly open area.

I am wondering about the concrete slab. I'm thinking 4 inches should be pleanty.

This slab would be supported by a buried wall 8" thick and 36" deep which is below the frost line. The wall would be formed, on the outside of the trench, with plywood to the level of the poured slab. the plywood would have a total height of 42". This wall would also be the footing...any problems so far?
Old 05-16-04, 06:04 PM
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Any applicable building code would prevail, but here is a table to calculate footings for load.

Hope this helps.
Old 05-20-04, 09:19 PM
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Hold up a minute..

Footings as much as people hate to admit it are a Pretty IMPORTANT part of the building... Make sure you check the local building codes, but generally a 12-16 inch wide footing is more than adequate... Again, please check your local building codes... Be safe and not sorry...
Old 05-29-04, 10:21 AM
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Where I'm located rule of thumb is a footing twice as wide as the wall that sits on it. 8" wall 16" footing, but find out what the code for your area is.
I don't know exactly what you have planned but it seems to me you'll have a hard time holding plywood forms on one side. It would require a lot of kickers
to hold it from moving or giving-way. Might be easier to dig the hole wider,
pour footings, then rent forms to pour your walls.

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