Poo In The Shower and Foundation Subsidence

Most people think water restrictions is the worst thing that can happen during a drought. However, the risk of foundation settlement is a far greater threat to a home owner or buyer than losing a few plants due to lack of water. A foundation affected by drought conditions could cost you thousands and is far more difficult to fix than replacing a few plants in your yard. As I write, your house (or the house you are about to buy) may be affected already. It is vital that you take action now if you own a property. Or if you are buying, have the sewer line inspected using a sewer cam. Subsidence under a house often shows up in the sewer line long before it visually affects the foundation and structure.

Soils in North Texas contain highly active clays which exhibit a high degree of expansion when wet and shrinkage when dry. (When it's dry all houses in the DFW area go down; when it is wet they all rise.) This situation can result in severe vertical and/or lateral displacement of supported structures. Repeated variations in soil moisture content cause differential movement and undue stress to the structural elements of a building, resulting in broken and unlevel floors, masonry cracks and misalignment of doors and windows. Consistent soil moisture content is the key to controlling these problems. In this blog I will first tell you how to determine whether a property has the symptoms of foundation settlement before cracks in the walls, ceilings, and floors appear.

Whenever soil cracking occurs or you notice that soil is pulling away from the foundation, it is a signal that soil moisture levels are too low. Look carefully at the following two photographs of a house I inspected recently. The property is pier and beam and the first photo shows that the grade has pulled nearly an inch away from the foundation.

The second picture shows a steel rule lowered into the gap that has opened up and you can see it goes down close to 10 inches. This means that a large portion of the grade beam is not supported!

These photographs illustrate the problem in detail. Now you can go and make your own observations around your own property or the property you are considering buying. If you follow my instructions you will be able to expertly identify if the house has a potential problem.

Start on the south-facing side of the property and look to see if there is a gap between the foundation and the grade. Look carefully at the area along the grade walls. Do you see a gap? If so, can you get your fingers into the gap?

The sketch above illustrates how to make a positive identification of the grade pulling away from the foundation. (This simple test is the same for slab or pier and beam foundations.)

If the property has this condition, go into the house and look at the doors, floors, walls and ceilings. Do you see cracks in the sheetrock? Are any of the doors sticking? Are there cracks in the floor tiles or are the floor boards moving apart? If you have a gap between the grade and the foundation you have a potential problem. If you also have cracks then you definitely have a problem!

So what do you do if you find these conditions? If you own the house or are buying it, consider having the foundation evaluated using a ZIP level to measure how level it actually is.

The ZIP level allows the inspector to measure the variation in the slab level to withing 1/10" and this information can be critical when making a decision to buy. The measurements are made using the ZIP level during the inspection then uploaded to a computer for a detailed analysis.

In addition, have a sewer cam inspection to see if the sewer lines have been affected. The sewer camera allows the inspector to find bellying in the line caused by subsidence. The sewer line is a gravity-driven system. The line must have at a minimum, a continuous 2% slope that runs downward all the way to the public sewer. Water doesn’t flow uphill. When the sewerline gets shifted for whatever reason and lays flat or even has a turn up hill, this creates a belly in the line. Water and debris backup at a belly and can clog the line and you get poo in the shower or worse!

Remember a sewer back up can destroy your flooring, carpets and even the sheetrock on your walls -- not something you want!

The ZIP level and Sewer Cam will add a little to the cost of the inspection but can save you from buying a money pit.