Causes of settling/how to minimize settlingExpansive soils equals settled concrete

January 18, 2014by Jerald Sargent

slabjack logo

Do you have slabs that seem to rise and fall with the seasons?  Then you are likely dealing with expansive soils, in our area, generally clay. Much of the United States has expansive clays to a greater or lesser degree.

In a typical year in the United States, expansive soils cause a greater financial loss than earthquakes, floods, hurricanes and tornadoes combined.

Clay in and of itself isn’t the problem, the problem is the change in moisture content.  If the moisture content stays the same no swelling or shrinkage will happen.  In Washington State, and in particular Easter Washington, we have four seasons where we can expect cold wet winters followed by warm dry summers.

When we combine expansive soils and wet winters followed by dry, hot summers, heaving and settling are to be expected.

I personally have one section of my driveway that magically rises from the ground about 3/4″ each spring and as the ground dries, settles back down.  Not surprisingly it is on bare soil with no gravel bed.

Some people call to tell us their slabs used to rise and fall, but now they are staying up, why?  First let’s try to eliminate the issue.  In my case the section that rises and falls is the lowest of six driveway panels, water seeps between the expansion joint when it rains or snow melts, (I really should seal that joint) saturating the underling soils causing expansion.  As the summer heat comes on, the soils dry allowing the slab to settle.  To reduce heaving and settling, seal all expansion joints on your concrete. A good, inexpensive product is Sika brand (Home Depot) or Quickrete brand (Lowes) polyurethane caulking.

If slabs are not resettling as they used to, then two issues may be in play;  first, debris washes under slabs which cause the slab to remain high, this is very common. Second, you may be over watering your soil keeping it saturated and swollen.

When expansive soils shrink, fissures can open up which allow water to run off and carry away soils, causing settled concrete slabs along with cracked and damaged driveways, porches and patios.

The key to building on these type of soils is to insulate concrete as much as possible from the soils. Gravel should be used as a foundation in the construction of driveways and walks.  Caulking along seams and  joints and along foundation walls minimizes water penetration under slabs and, especially important to basements, making sure concrete slabs are not settling toward foundation walls draining water along the basement walls.

If you have sunken and settled concrete call the concrete raising and leveling professionals 1-855-752-2522, for a no cost, no pressure estimate to have your damaged concrete raised back to proper grade, using state of the art Geo-Polymer injection technology.

Superior equipment, superior Polymers, superior Training, producing superior results.

Full article found here“>“>

Leave Us A Review Below:
50 reviews Home Advisor
10 years with Home Advisor
top rated Home Advisors
bbb logo 2023
Proud Member of:


630 Valley Mall Parkway #431 East Wenatchee, WA 98802

Hours of Operation:

Monday – Friday: 8am-5pm

Saturday & Sunday: Closed

We have local branches serving Idaho and Washington.

Contractor License #SLABJG*833K2

Slabjack Geotechnical, 2020 © All Rights Reserved