Foundation repair can be the most expensive repair that you will make to a property. One of the saddest things I’ve heard in the investment community are the stories of investors who have purchased a property, rehabbed it, and put it on the market only to have the buyer’s inspector tell them there was a problem with the foundation. Foundations can be very expensive to repair, and repairing them after the house has already been fixed up and painted can mean redoing a lot of sheetrock and paint work. All of this means money out of the investor’s pocket, and if the expense goes deep enough, it just might wipe out your profit.

Part of my mission on this planet is to help keep the investor’s money in his or her pocket. It comes under the heading of “Comforting the disturbed and disturbing the comfortable” in my charter. That’s why we are going to learn how an investor stays out of trouble when a house has a foundation problem. We are going to talk about what the foundation does, what causes problems with it, how to tell those problems, and how they go about fixing them. This is the lecture portion of the foundation training. To get the required lab, you’ll have to go with me on an inspection. I will show you all about it and soon you will be able to make the evaluation of the foundation with a certainty born of knowledge and experience. Sounds good, huh? Let’s get started.

The foundation of a house, whether it is a concrete slab (slab on grade) or a block and beam (pier and beam) foundation has a job. The job is to keep the house level and stabile. When the foundation moves up or down or side to side, then the platform that the house is sitting on enters a state of failure. It is failing to perform the function for which it was intended. What this means is that everything that was depending on the foundation for support is now in jeopardy, because the support is no longer there. It is like one of your legs suddenly becoming 2” shorter than the other one … it has consequences for the way you stand and the way you walk.

When the foundation is no longer doing its job, there are certain tell tale signs that appear. Here’s what to look for when you are checking out the house before you buy. On the outside, look for cracks in the brick veneer. These cracks may be stair-step, vertical, or horizontal. There may be cracks in the grade beam (the part of the concrete slab that you can see at grass level), and there may be a separation between the doors or windows and the siding that comes up against those doors and windows. The cracks next to the doors and windows will look like a long skinny pie slice with one end open wider than the other, or it may look like. Stand at one corner of the house and look along the mortar lines or the lines of the horizontal siding. If there is a deflection (a rising or falling of the foundation) then you will most likely be able to pick it out here.

On the inside, look for cracks radiating diagonally from the doors and windows in any direction. Look at the tops of the doors, do they have that little pie slice between the top of the door and the door jamb? Do the doors open, close and latch properly or do they stick? Are the windows operating the way they should or are they jammed? Now look at the floors. If there is hardwood flooring and the foundation has moved, you will see little cracks open up between the sides of the boards where they abut one another, and you may also see where the boards have separated end to end due to the stress of the foundation moving.

Now get out your 4’ level and go from room to room. Put the level on the floor near the outside wall of the room at right angles to the wall. There is a bubble in a little glass vial in the middle of the level, and on either side of this vial is a line. The bubble has to be exactly in the middle of these two lines for the level to be sitting level. If you have to lift up one end of the level to get the bubble to go between these two lines on the vial, then you have deflection. Deflection means the floor is not level and foundation has probably shifted. The distance between the floor (carpet, tile vinyl) and the bottom of the level is the amount of deflection in 4’. The allowable deflection is ¼” in 4’. If you have to lift the end of the level up ¼” or more, then you need top have the foundation looked at by a licensed structural engineer or a reputable foundation contractor.

Once you have checked the floor with the level at right angles to the outside wall of the room, turn it to be parallel with the wall. In other words, you have checked the foundation from left to right, now test it from front to back. Go from room to room and check all the floors. You can also put the level on top of the door trim and on the window sills to check for level as well. Again, the maximum allowable deflection is ¼” in 4’ before you need repairs.

We know about the doors and windows and sheetrock cracks, but is there anything else that happens to a foundation? Yes. There can be damage to sewer lines that run under the foundation, they can become separated or broken, and then you have to dig them up to fix them. That gets expensive. Gas lines are forbidden to be placed under concrete slabs, but some people put them there anyway because they think that it is more convenient for them. If a gas line gets ruptured under a slab it turns into a very expensive mess to repair. The other thing we see is that water lines, especially the line that comes into the house from the water main, gets pulled apart when the slab gets raises again.

What I have told you about checking out foundations by looking for separations and checking the floors also holds true for block and beam foundations as well. Block and beam and pier and beam are the same for purposes of this discussion, they both mean that the house is up off the ground. The main difference between pier and beam and slab on grade is that the pier and beam house will move more than the slab house. That means that the front door sticks when the weather gets dry for awhile, and then it will work just fine again three days after the rain comes back.

What causes all of this hopping around of the foundations? Clay, mostly, black gumbo clay. The type of clay that we have in the majority of the subsoil; in this part of the country is a nasty black material. It is hygroscopic, which means that if there is water in the soil surrounding the clay, then the clay will attract and absorb the moisture. When it does this, the clay expands like a sponge. When it expands, it increases in volume and lifts everything that is sitting on top of it. When the moisture level of the soil surrounding the clay drops, as in a drought, then the moisture will migrate out of the clay into the surrounding soil to be evaporated back into the atmosphere.

So now you know what to look for when you’re looking at a foundation repair, and why it does the foundation does things it does. In the next post I’ll tell you about the different ways to fix foundations, both slab and pier and beam, and how you can prevent this from happening to your own home or your rental properties.


Kevin Smith
Forward Assist Inspections
(713)858-1330
Texas Real Estate License #3234