Footing or thicker slab?

[kyles974]

Hello,

first, great site! I've learn alot here. Love reading, etc., Great people equeals a great site!

I need some opinions on what to do here;

NW Florida build. High water table with a 24x36 metal/steel building.

The place I'm going to buy my building from says to have a 6 inch slab with rebar. Well, I thought a 4 inch slab with wire on a 12x12 inch footing would be the way to go?

Need some feedback please!?

 

[Frank The Plumber]

With a high water table you may end up with pressure exerted by that water upon the bottom of the slab. I would personally if it were mine remove maybe a foot of soil from the planned base, use a high compaction substrate and pour a heavily reinforced 6" pad. I would also place precuts in it to control the inevitable stress cracking. I would at the least use a 12" deep footer around the perimeter and tie this back into the slab.

 

[rburke65]

As a rule, you shouldn't have to reinvent the wheel. If they are telling you that you need a 6"floor, there is reasoning behind their suggestion. Just my 2 cents.

 

[kyles974]

so Frank, you are saying both 6 inch and a footing?

(I lived in Michigan most of my 36 yrs, there, a footing and 4 inch with wire always seemed to be fine,.... this is why I'm asking

 

[aabirdman]

I've never installed a slab for a building without a footing. If you don't use a footing what supports the wall and roof weight? Your just asking for slab cracks without a footing IMO.

 

[toolman1967]

Whatever thickness slab you use, I went with 4 inch, install a good deep footing. It will set the slab from heaving or sliding with a high water table and leave a solid foundation for the walls.

 

[Justanoldguy]

Use a footing for sure.
Here in New Zealand, nothing gets built without a footing.
Good assurance it won't move at least.
Slab thickness, I reckon, is personal preference.

 

[gnxtc2]

I think the OP is talking about a pre-fab metal building that gets bolted down to a slab. I have no experience in this, just heard about them.

Billy T.
[email protected]

 

[djjsr]

I always thought a deep footing was to stabilize the foundation by getting it below the frostline. Does Florida even have a frostline? Follow the building code.

I had a house in California that was built on a 10" slab, rebar and no footing. That was code for the area because there was no frostline and the slab was designed to "float" during an earthquake. It did, several times.

IMO, wire is almost useless for any slab that will be supporting a load. It won't prevent cracks for anything but a patio.

 

[kyles974]

@ gnxtc2 ........yes, you are correct. Not a heavy building. The cabinets/shelving and everything else I end up putting in the shop will most likely be much heavier the the building.

I just wanted some of your opinions, thanks
(I never heard until now to have a slab without a footing, but I will check local codes here, thanks again)

 

[burleymike]

Growing up in Colorado everything had a footing 4' deep. Then I come to Idaho and I have seen many buildings with a footing 2" wider than the stem wall and only 6" below grade. My neighbors house is done like that. Been there 25 years and no cracks or sticking doors. Talking to the county the frost line is 2' and they said the footing should be below the frost line, yet many many places are built like this and don't have any problems.

I would call an engineer and pick his brain. I have done that many times and most of them have been more than willing to talk for free, one guy spent an hour on the phone with me on how to do my basement drainage system.