I suspect that many people do not spend much time reading the terms and conditions that come with repair proposals. If they did they might ask a lot of questions. They might even rethink the need for foundation repair.
How repair contractor proposals offer a roadmap to foundation repair risks
Consider that foundation repair contractors understand the risks associated with foundation repair better than anyone else. Better than even some engineers. Should the repair go south, there is likely to be a very unhappy homeowner and it is likely that there will be a lot of fingerpointing arguments about money.
Reputable foundation repair contractors do try to minimize risks to the extent that they can be mitigated. They do this by training their crews and providing experienced supervisors to make sure the job is successful.
Foundation repair contractors use repair proposals to identify risks that cannot be avoided. In some cases, a repair contractor might agree to absorb more risks if the owner is willing to pay more money.
The goal of slab-on-ground foundation repair?
The goal is simple: make the foundation surface more level. Unfortunately, levelness is an aesthetic issue. From an engineering perspective, it is better for the foundation surface to be level, but levelness is not an important structural characteristic. Stability and stiffness are far more important from an engineering perspective.
To give the contractor his due, the typical proposal also says that it is their goal to stabilize the foundation and to prevent future settlement.
You might ask: If levelness is not important, why do repair contractors focus on how level the foundation is? The answer is simple: pilings and piers can be used to lift low areas and this makes the slab surface more level. Just as a carpenter sees the world as consisting of nails in need of a hammer, foundation repair constructors see low areas on a slab-on-ground foundation as in need of being lifted.
Theoretically, a foundation could be made more level by grounding the high areas ground down, but this is rarely economical.
Let’s look at the goals to stabilize the foundation and prevent future settlement. This can only happen if the piles are driven to a depth below where the soil moisture does not change much. The problem is that the appropriate depth cannot be known without a soil report made by a Professional Engineer. The cost typically runs between $800 to $1,200. Future settlement can be reduced by foundation repair, but settlement is rarely the source of s serious problem.
Heave is much more of a problem than settlement. Foundation repair has no effect on heave. Any risk that the foundation will heave in the future has to be borne by the homeowner.
The foundation is to be made as level as the house will allow
What does this mean? There is no promise to make the foundation level.
Consider that as low areas are lifted, the brittle wall and floor coverings will inevitably be stressed and may fracture. Once the house reacts in a visible, adverse manner, the lifting will cease. The house is, in effect, saying loud and clear that the lifting must stop: the house cannot tolerate more lift.
Consider the implications of this. Let’say that one area is 2-inches lower than the rest of the foundation. The initial lift will be 1/2 inch. As the low area is lifted, the brick veneer fractures and the drywall cracks. The contractor now wants to lower the area the was just lifted.
The cost of the work is not known when you accept the repair proposal
The proposal probably states that the cost can go up for a variety of reasons. Some work such as sewer line inspection is typically charged at $135 per hour.
In addition, the contractor is not normally responsible for leaks in water and sewer lines, damage to any utilities above or below grade. These include sprinkler systems, plumbing leaks caused by the lifting process and landscape lights.
The owner is normally responsible for moving any air conditioning and pool equipment. The repair contractor is not normally not responsible for any collateral damage.
A bunch of other things that drive up the cost to the homeowner
There are conditions that might appear only when or after the work begins. Examples include insufficient or damage that were nor obvious prior to the start of the work such as insufficient reinforcing steel, poor subgrade condition, inadequate drainage or improper construction methods. A perimeter grade beam normally not deeper than 3-feet. When the grade beams are deeper than 3-foot, there will be additional costs.
At the end of the day, it may simply not work
There is a church not far from where I live. When the structure reached around 40-years in age someone noticed that there was a floor slope at an inside corner. A decision was made to call in a foundation repair contractor. (no engineer was consulted so far as I know). The contractor was reputable and had been in the business for many years.
When the work was started, the foundation refused to move. They tried everything they could think of but nothing worked.
No one was happy, but an agreement was reached that everyone could live with.
I would never recommend underpinning to address a floor slope issue. There are alternatives that are much more cost-effective.
The engineering certification
The typical proposal for foundation repair includes providing the homeowner with an engineered certification of the pile layout. There are costs involved, but more importantly, this is likely to be misunderstood. The certification is required to get a repair permit. It is not a certification that the repair plan was made by a Professional Engineer. I strongly suspect that, in the large majority of cases, the repair plan was not made based on a soil report and the engineer never visited the site before or during the repair.
At the end of the day
The typical situation almost always holds. When you sign that repair proposal:
You do not know what the final cost will be.
You have no idea how well or poorly the repair will work. Making a judgment of how well or how poorly foundation repair works should not be made until a couple of years have gone by.
You will not get the best results unless any drainage and any tree or other vegetation issues are corrected. I frequently see homes that have undergone foundation repair with obvious drainage and tree/vegetation issues that have not been corrected.
At the end of the day, you will get the pleasure of writing a large check still not knowing what the final results will be.
Count the costs
Jesus warned his disciples that they should always count the costs before starting a project. I would caution any homeowner to count the costs and understand the risks before deciding to underpin a slab-on-grade foundation.