Watering your foundation may be more psychological than an engineering requirement
Some engineers blame foundation movement to homeowners because the engineer did not observe soaker hoses watering a foundation. Interestingly enough these are Engineers who are hired by the home builders. So we went through manyl of our engineering design manuals, building code, theories, and software to look for the engineering parameters that influenced the foundation design if the foundation is watered or not watered. Not to our surprise we found NOTHING in terms of accounting for a soaker hose. Anyone that blames you for not watering the foundation simply doesn’t know what he is talking about. We design foundations to react to the movement of the soils based on the soil classification, relative moisture content and climate. It is important to understand that foundations are designed to move. Especially those that rely on the near surface soils for support. Let’s discuss each parameter:
Considering the three general foundation design factors together, if we design the foundation for your house there is no way for us to take your watering effort into consideration. We simply design for a worst case scenario which is a foundation on very dry soil that gets wet and swells up based on the historical regional factors previously discussed. If the foundation soils dry out and shrinks then the foundation design effects are the same but in the opposite direction. Something else to consider is the basic observation that the soils you are watering are not the soils that support your foundation since they are next to the foundation and not below it.
A very important factor that does influence the performance of your foundation is the depth the foundation is below the ground. The deeper that your foundation is the less susceptible it will be to the climate. The International Building Code states that all foundations should be at least 12” below the adjacent soil. This is a minimum. A depth of at least 24” into natural soil will be less susceptible to moving soils, plus the beam will be stiffer and more capable of withstanding soil movement better than a shallower beam. If you hire your own structural engineer to design your foundation you should insist on a deeper beam – 3ft deep minimum in San Antonio and Austin is our suggestion.
There is obviously a cost increase in the construction of the foundation but this cost will be substantially less than foundation repair later. So having a blanket recommendation to water your foundation falls short of the full consideration that structural engineers take into account for foundation design. Simply put, any engineer or home builder who tells you that you didn’t water your foundation is the problem is not clear or doesn’t know anything about foundations.
Does an engineer inspect the work of a foundation repair company?
Foundation design, performance and leveling are complicated concepts to understand because a variety of factors influence each other. When a foundation repair company states that an engineer certifies the work of their press pile installation they are referring to an inspection that an engineer performs to tell you what the contractor did, how they did it and the engineer may report the relative elevations of the foundation after the work is completed. The key point is that the engineer is asked to inspect the work after the fact. The inspection by the engineer does not consider a structural assessment of your building or the foundation. So if your foundation, walls or roof framing are broken then you will need to hire another engineer to assess the building, however you indirectly paid for the first engineers inspection. Many of the engineers that inspect foundation “repair” work are not structural engineers. Why does it make a difference? Because once a foundation beam is lifted off of the ground it is no longer a soil supported beam, it becomes a true structural beam. Beware of Engineers claiming they are Structural Engineers when in fact they are not. For more info on engineers pretending to be Structural Engineers, please read Structural Engineering License in Texas.
This may sound confusing so lets discuss the difference. Basically a structural beam is a beam that spans between two points; similar to the beam that is over your window. The beam over the window spans from one side of the window to the other. A typical foundation beam is not a structural suspended beam because the beam is continuously supported by the soils, it’s considered a structural foundation, usually called a strip footing. It does not span between two definite points so structural engineers do not design foundation beams in a similar manner as a structural beam. So if the engineer that inspects the foundation “repair” is not a structural engineer they may not understand this difference and NOW a full structural beam (which is supported from pile to pile) may exceed the allowable span which is not permitted by the International Building Code (the actual code). Foundation repair companies will not ask the engineer if he/she is qualified to inspect the foundation (because they don’t care… see foundation repair page) so its imperative that you seek the engineers qualifications.
If this was a little too technical of an explanation, we have “translated” this article under our page entitled Water Soaker Hoses for your Foundation.