Concrete slab questions...

[Capt. Jim]

What can be done to ensure that water doesn't get between the foundation and the slab and cause this mess again?

As small as those slabs are, I doubt any leakage between the slab and edge of the structure is contributing to excess water in your sump system. I also don't think any such leakage contributed to the soil erosion you described. Be sure not to overlook something else.

Also 4000 psi concrete mix would be way overkill. Use 3000 psi if you need to pump it. Otherwise, 2500 psi is more than adequate.

 

[Toyo FJ40]

I would just pull the slab, regrade with gravel and compact it. The new slab should be fine. What usually happens is the slab is pored onto dirt that was just pushed back into the footer trench. As the dirt settles it takes the slab with it. If the area had been compacted first it probably wouldn't have moved.

 

[constructeur]

Ib-

If you care to research it, all the engineering standards and specs are available online for your respective city: City of Wichita - Engineering Standard Specifications

You should find all necessary info under section 300 and 400.

Three other thoughts are:

1. All 'borrow' materials are considered engineered soils, some are designed for structural integrity, some for water flow. Keep that in mind when you're backfilling.

2. If you do have a clay issue you may want to lay down a layer of 5 oz. filter fabric before you backfill with gravel. If you look at clay under a microscope it's essentially the finest silt imaginable, and the dense fabric helps keep infiltration into your drain or structural gravel to a minimum for a longer period of time.

3. I'd use a jumppingjack to compact into that small tight area. You'll be looking for 95 plus % compaction, and foot stomping or using a hand tamper just won't cut it.

So far you've had lots of opinions from all corners of the country (me included) but the link I gave you should help you on the path to how your local engineers have sorted out how to best deal with your local conditions.

 

[IBCRUSN]

Awesome, thanks. I have tried to read through the Wichita City code for other projects and I always end up with a headache.

Ib-

If you care to research it, all the engineering standards and specs are available online for your respective city: City of Wichita - Engineering Standard Specifications

You should find all necessary info under section 300 and 400.

Three other thoughts are:

1. All 'borrow' materials are considered engineered soils, some are designed for structural integrity, some for water flow. Keep that in mind when you're backfilling.

2. If you do have a clay issue you may want to lay down a layer of 5 oz. filter fabric before you backfill with gravel. If you look at clay under a microscope it's essentially the finest silt imaginable, and the dense fabric helps keep infiltration into your drain or structural gravel to a minimum for a longer period of time.

3. I'd use a jumppingjack to compact into that small tight area. You'll be looking for 95 plus % compaction, and foot stomping or using a hand tamper just won't cut it.

So far you've had lots of opinions from all corners of the country (me included) but the link I gave you should help you on the path to how your local engineers have sorted out how to best deal with your local conditions.