SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

I am installing an emmitter line around my slab to help with shifting or settling. This was suggested by an engineer that I met. I have assembled all of the equipment needed, but I do have one question. I am going to bury the line 12" from the slab and 12" underground. I have alot of clay in my soil so I am concerned with absorption. My question is should I put a layer on sand or pea gravel on around the emmitter line?

In coastal Texas the houses are built on a 4" concrete slab. This slab basically sits right on top of the ground. We have very high clay content in our soil. If you think about clay it will shrink when dry and swell when wet. In this area we are in a severe drought which has made the ground shrink alot. I have cracks in my yard that are 2" wide due to lack of water. In the winter we tend to get large quantities of rain which cause the ground to swell. Now think of that 4" slab of concrete sitting on top of this very unpredictable surface. Concrete does not bend very well it tends to move up and down with the soil this causes cracks in the walls and floors of our houses.This cracking in the house is very destructive and demoralizing to a homeowner.Now this is a basic explanation of the house foundations in Texas there is engineering in the design of the slab, but I just wanted to give an idea of what I am talking about.

The answer to this problem is to control the moisture in the soil. If a person can control the moisture level they can minimze the damage that is done by our irradic weather.I have read engineering studies that claim a soaker system placed 12"from the slab and 12" underground that is closely monitered can help with slab movement.

This is the system I was describing in my first post. I plan on installing a 1/2" emmitter house all the way around my slab. The line will be hooked into a standard sprinkler system. The system will have a scheduled run time and be equiped with a rain switch that can shut off the system if we get to much rain.

My question in the earlier post was about puting a bed of gravel underneath and on top of the emmitter hose to help the water be absorbed into the high clay content soil.I have decided to put 3" of pea gravel below the emmitter line and 3" above it. Then I will cover the trench with the excess soil. I will monitor the moisture in the soil and set the timer as needed.
The reason for my concern is that we have just spent alot of money replacing flooring and patching walls and painting.

I don't know if I am right in my decision, but I have made up my mind. I hope that this post will help other people in their pursuit of a stable foundation.I will post my results in a few months.

Linear absorption was a major factor in my decision to use the gravel but I am also concerned that the heavy clay soil will clog the emmitters. My thought is that the gravel may prevent this from happening.