Fact: MOST Foundation Repairs leveling DO NOT WORK !
The most common type of foundation leveling repair done in Austin and San Antonio, Texas, is the press pile or push or forced pile. Most geotechnical and Structural Engineers (who are not associated with a foundation repair company) know that this type of repair is temporary and hence does not fully work. By the way, read also FREE Foundation Repair Inspections.
This is a fact because the Engineering formulas and building codes used for foundation design clearly deduce that the science behind foundation leveling repair using these concrete press piles is temporary; nobody knows how long a house or structure foundation will remain level before additional foundation repairs or re-leveling are required. Not only many foundation repair systems are not reliable, but many times foundation repair is not necessary and sometimes even not advisable; We can help you make such a determination.
In our experience, foundations go bad (i.e. need re-leveling) as soon as 6 months after the repair and as late as 10 years. Because we’re unable to apply engineering principles to measure any consistent effectiveness of this system, then we believe installing such as system may be as just reliable as hitting heads or tails in a coin flip. The following article is meant to educate the general public and assist in making the right choices.
By the way, for those of you who are more technically inclined, please also read Concrete Press Piles Foundation Repair does NOT meet the building code
Please also read other popular articles before spending a dime on a foundation "repair", How to successfully help to sell a house with Foundation Problems.
By far, the most common type of foundation repair used in San Antonio and Austin Texas is the press Pile or Push or forced pile. Unfortunately, this is for the most part also one of the most useless and ineffective types of foundation repairs. This is not just our opinion, but also the opinion of many, if not the vast majority of, independent engineers (structural engineers and geotechnical engineers).
A Press Pile or Push Pile foundation repair consists of cylindrical concrete pieces, usually 6” in diameter x 12” in length, which are pushed or pressed down into the soil and below the existing foundation beams through the use of a hydraulic jack using the weight of the house. Sometimes these piles might be called piers, but strictly speaking that’s not the correct terminology. These cylinders are considered precast concrete driven piles, which the building code says would need to be at least 8” in diameter in order to meet code (yes, without even going into calculations and formulas and complicated Engineering stuff, this system is code non-compliant already).
The intended purpose of this repair system is that as you push down these round concrete sections eventually you will reach soil that is very hard or stiff, not necessarily rock (actually, most of the times it is not Rock, especially in San Antonio). Usually this is known as driving until refusal. Once you have reached this very stiff stratum of soil (supposedly), the hydraulic jack won’t be able to keep on pushing the sections of concrete down because the force required to push the piles down is more than the proportional weight of the house; at this point, the hydraulic jack will start lifting (leveling) the existing foundation of the house. We ought to say that even this very stiff stratum of soil may in fact not be a very stiff stratum of soil but instead the very same bad soil; it may just be that the friction of the soil, or the accidental tilting of the sections creates a bigger bearing area, or whatever other reason, are preventing the concrete sections from being pushed any further.
The Picture above shows what a concrete cylinder used for a concrete press piles foundation repair looks like. Other Similar and equally bad systems would have a hole down the center to run a cable through it.
Different types of Foundation Repair systems, Most with the same FLAW
There are different types of systems but all they are is mainly a slight variation of the same push pile or press pile foundation leveling repair system. Some companies put a cable through the different cylindrical sections, other companies put a steel pipe at the bottom and then put the typical push piles on top. Another system uses a combination of steel pipes with concrete push piles, while others use 100% concrete sections and inject water or some chemical by hand in to the surface of the soil.
The reason there are different systems that are basically slight variations of the original system has to do mainly with competition. Foundation repair companies need to differentiate themselves from each other because after all there are literally dozens and dozens of foundation repair companies in Austin and San Antonio, so they need to claim their system is better than their competitors. But also, foundation repair companies are interested in getting patents for each system they come up with, thus presumably giving them the upper hand against their competitors.
Mostly all of these systems do not effectively repair or level a foundation because they mainly share the same flaw. This flaw is that the piles themselves are not deep enough and do not act monolithically (i.e. don’t act as one piece), and because they are surrounded by bad soil, then the piles will be subjected to the same heaving and settlement that the original slab is subjected to.As long as concrete push piles (in sections) are used, the foundation repair system will almost always be temporary.
Why most push or press pile Foundation Repair Leveling systems do not work
There is a zone in the soil known by geotechnical and Structural Engineers as the active zone. This zone is simply a certain depth of soil in which variations in moisture content (i.e. water) varies as the environmental conditions change (e.g. change in temperature, rain, exposure to sun, etc.). As long as a foundation is bearing within this zone, then a foundation will move depending on the moisture content in the soil. If the soil is dry then the soil (clay) will shrink and the foundation will settle; if the soil is wet the soil (clay) will expand and the foundation will heave.
But the problem of bad soil in the active region also affects piers and pile foundations, regardless whether they bear below the active soil. The reason is the changes in water content in the soil creates suction in the surface of the pile or pier (i.e. swelling of the soil pushes on the pile through skin friction), thus making the pile or pier heave up. Yes, you read right, the pile or pier will move up! The problem also with press piles is that although the piles are pushed into much harder soil (or so they claim), this soil is still bad soil within the active zone and therefore, will move up or down as moisture in the soil changes.
A way to prevent heaving or settling of a press pile foundation repair system is by ensuring that the entire pile works as one unit, monolithically, and extending to a sufficient depth so that it stays away from the soil active zone and it prevents uplift of the pile… This is just almost impossible for a press pile, even for those foundation systems where the post tensioned cables run through the middle of the pile! This is because the cable goes through what is called relaxation and the force on the cable might be too small (sometimes too large and it breaks the cylinders embedded into the ground without the installer knowing it) or not effective since the pile is usually not straight when it is pushed into the ground. The cable is also not protected from rusting. Eventually clay soil will get in between the sections and keep on pulling the pile apart (again, most of the times the piles will not reach below the active region anyway, so it doesn’t matter even if you are able to install a full monolithic section, the pile will still eventually move). Don't be misled by companies who claim they have been around for 20, 30, or even 50 years – If you’ve been painting for 50 years it does not make you Picasso, neither having 50 years of experience doing a repair mostly the wrong way make the foundation repair installed any better. Coincidentally, we learned recently (2011) that one of these biggest and most famous major foundation repair companies who provide a similar system had to file for bankruptcy protection after many homeowners decided to get together an get a lawyer involved.
Interestingly enough, many foundation repair companies will tell you that they pushed the press piles down to 10ft or 12ft in San Antonio, for example. They are in fact telling you that, if the piles were pushed exactly straight (highly unlikely) they have not gone well past the generally accepted depth of the active zone, which by definition means that the piles will eventually move even for those systems that claim to positively connect the cylindrical pieces to each other. In other words, many foundation repair companies are telling you and admitting from the beginning (without them knowing) that what they are installing will likely make your foundation move again.
The Picture above shows the Final product in a concrete press Pile foundation repair. Not a good idea...
here are many negative side effects to foundation leveling repair through concrete press piles. The first negative side effect is that you will likely develop more cracks in the walls and slab than you did prior to any foundation repair. Ideally, when you push up on the foundation the cracks should close, but in actuality the way the lifting operations are done will result in additional cracks.
Another negative side effect of leveling the foundation through press piles is that you may damage plumbing that goes underneath the slab and thus creating even a bigger problem than you had before doing the foundation repair.
You may also distort the roof and therefore create leaks which you may not have had before. Do you have floor tiles? They will likely crack too.
Eventually, many of these piles will move and re-create the damages you had before.
Picture of Foundation Repair with concrete Press Pile Filled with water. The press pile now becomes a "magnet" of water. Congratulations, your foundation is now worse than it was before.
Many of these foundation repair companies will tell you that your foundation is moving and you need a repair.
Let us start by saying that all foundations on soil move, the question is whether the movement is within some sort tolerance and whether the movement has compromised the structural system. If yes, the foundation has moved and yes, the structure has been compromised, then as we have discussed earlier, the foundation repair that most concrete press pile foundation repair companies suggest to do is mostly useless and almost completely a waste of your money because nobody knows when this "repair" will fail again. Please start flipping a coin, because your guess will likely be just as good as ours.
If you have any doubts about what you’re reading please ask your neighbors and people who have had this type of foundation repair done on their house (and we would suggest not relying of the reviews you find on the internet). Many, if not all of the people who have had this type of foundation repair done, will tell you that the foundation repair company has had to go back (several times in many cases) to re-level the foundation. Meanwhile, the cracks in the floors, walls, and ceilings re-appear, possibly plumbing leaks re-occur, and many other damages happen, most of which, if not all, are not covered repairs by the foundation repair warranty.
It seems to us that one of the main purposes of a foundation repair is to reduce the possibility of damages from continuing to happen; if you perform a foundation repair and the damages continue to appear, then it appears obvious in our opinion that one of the main objectives of the foundation repair has not been achieved.
However, many homeowners have discovered, through our help, that most of the time foundation movements are within acceptable levels and have not negatively affected the structure’s safety and the press pile Foundation Repair company is for the most part simply trying to sell them something that is not needed. While we do know some foundation repair companies that are honest people, the truth is that many and most of foundation repair companies out there only know one thing: if the foundation is not leveled then it must mean you have a foundation problem that they need to fix by "releveling".
Most of the Foundation Repair companies are just sales people in our opinion and you can verify this yourself when you get a few of them to visit you at your house. You will be amazed by the fact that if you get 3 companies to look at your foundation you will likely get 3 completely different answers on what and how many piles to install along with likely 3 completely different prices. Most of the ones who do have Engineers have also become sales people, attempting to sell you a system you probably don’t need and that doesn’t fully work more than perhaps just temporarily!
We don't want to make the public believe that the foundation repair companies are scam artists salivating to steal your money; Our point is that many foundation repair companies only objective is to raise your foundation that is not very level with a system whose effectiveness and reliability is inconsistent. They have no idea if the system works or not (we are giving them the benefit of the doubt on whether they actually know if the press pile system works); most of what they know is that this particular system (concrete section press or push piles) has been used by many people for many years and every time the foundation moves after the "repair" must be due to "normal" movement and it's not their fault. If you read the warranty terms and conditions most of these companies provide you will soon realize that it seems like not even they are confident in the performance of their product.
Look at the Size of that Crack. And they call this foundation repair?
Call us to schedule a consultation! We’re independent structural engineers in San Antonio and Austin Texas. We are not contractors. We simply assess and provide solutions for your structure and foundation, and we gain absolutely nothing by telling you that you have a foundation problem (we get no commissions from foundation repair companies). And if you do, we’ll advise you on what to do. But, many homeowners are surprised to know that many times foundation repair is not necessary and other methods could help you improve foundation performance. Our Structural Engineering advice could save you tens of thousands of dollars in unnecessary or faulty foundation repair. If you're buying or selling a house or building, our advice may be very valuable to you too. Please understand we cannot give engineering advice over the phone.
Allow us look at your foundation before anyone else has the chance to give you a sales pitch on how you should use their system and spend thousands of dollars to repair your foundation, when many times there’s nothing wrong with the foundation even if you see a few cracks. When there is something wrong, this press or push pile system is mostly not a consistently effective system.
Much movement of the Foundation and Cracks are not necessarily a sign of lack of Structural soundness; and if you're trying to sell or refinance your house then our expert opinion will not only save you thousands of dollars on foundation repairs you might not need but will also make it possible for the buyer to get a loan because the bank or lender will not release funds unless you present them with a letter from a Structural Engineer.
Please beware of some other engineers who make commissions from the foundation repair companies; we hope you agree with us that this is an inherent conflict of interest. For more please read Free Foundation Inspections by Engineers and Free Foundation Repair Inspections by Foundation Repair Companies.
Don’t be deceived by the many unethical engineers out there who claim to be engineers and claim to have 30 years of experience in design and inspection of foundations, there’s only a handful of us Structural Engineers out there servicing the residential industry. But even for those Engineers who are not structural engineers (Geotechnical engineers, civil engineers, etc.), everyone who knows about the science of foundation design also knows that most concrete press piles repairs do not work (meaning, the piles eventually move enough as to create noticeable damages). Please also read our article on Structural Engineer License in Texas.
By the way, for those of you who are more technically inclined, please also read Concrete Press Piles Foundation Repair does NOT meet the building code
For more on Foundations, visit our Foundation Engineering page.
Please also learn on the different types of Structural Foundation House Inspections