Foundation Question

Scott Young

there is a house that has a slab poured on top of the gound with no footing. the slab is sitting on the original top soil. the original contractor formed the slab, leveled the dirt inside the form and poured the concrete. there was no permit or inspection. this is in an area where code is not inforced. presumably the slab is 4 inches, but i don't know as i wasn't there when it was poured. the slab is sitting the gound with water undercutting when it rains. the gound is extremely spongy when wet. there is no metal and no fiber in the concrete.

the house is near completion and is soon to be inhabited.


now my questions are: is there a fix for this? if this was in a municipality that had permits and inspectors, and it was determined to fail the inspection what course of action would one take to fix the foundation?

this is new to me as i have always worked under permit and inspection. we had to have our tickets for dirtwork, termite exterminator, plumbing, etc. done before slab was poured. there was even the inspector that was there to check the slump if the pour warranted it.

i know the person who is the owner of the home who will end up having to deal with the stupidity of the previous contractor. complete destruction and a rebuild is not an option. as much as i hate the hassle of permits and inspections they do keep this from happening.

thom

You could excavate and pour foundations around the perimeter. Won't deal with interior bearing locations or the slab thickness issue. Obviously the owner made a big mistake in hiring this guy and will be paying for a long time. Even a sale is probably out of the question. Your friend would be required to notify any prospective buyer. Any bright prospect would walk.

WNYcarpenter

How do you know there's no metal in the slab?

Spectatorz

In the interest of trying to save the house...

Consider digging and pouring a footing as well as tying into the slab with 6-8" of rebar.
Maybe 1 or 2 walls at a time. If this was done at least there will be support for the Dead Load at the perimeter.
Then there will be an issue with water run-off and drainage. Maybe a French drain system will help.

I do not believe the slab you describe will hold up for very long under the weight.

Even this idea will cost some money and time to try and make this work.

Just an idea.

Good Luck

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woodmagman

Building on top soil is a real NO NO. even a drive way poured on sand or gravel that is over top soil sucks. The ground is organic and will never stop moving. If frost is not a concern, hydronics will be. I hope you can tunnel, the entire area under the slab should be cleared of all organic material and if in a frost area that means down to the frost level even if it is clay. You could lay out a grid and under pin the entire slab. I would assume the worst and consider the pad having no steel. Even not using an engineer and professional labour the cost of the labour is going to make it cheaper to jack up the house, excavate and do it right