Are Foam Injections and Piles Equal?

We would love to hear from you, click here to comment!

Recently I have become aware of the practice of substituting urethane foam for piles in foundation repair. Are they equal? Can one be substituted for the other?

Helical and push piles offer the advantage driving to a deep loadbearing strata for support and attach mechanically to a point loaded footing with brackets specifically designed to accommodate those loads. Although piles can be used to raise and stabilize slabs and paving, I don’t think they are ideally suited for that because of the inability of the slab to span between piles effectively. For those situations either mud jacking or urethane foam grouting is usually a more suitable repair technique.

Urethane foam does offer some advantages as a mud jacking technique balanced with its costs, which typically  can cost a little more. Mud jacking or foam injection by definition does not improve the soil conditions that support loads. So unless the foam is improving the soil at a deep level it will not be effective in permanently stabilizing foundations.

So can urethane foam improve soil conditions at deep levels? I argue persuasively in my previous blog grouting smoke and mirrors part two that it does not. 

http://www.foundationaz.com/2014/05/grouting-smoke-and-mirrors-part-ii.html

No third-party testing data has shown conclusive proof of deep soil densification with injection of urethane foams. In my blog cited above I actually show evidence of the opposite.

While urethane foam does offer cheaper costs than piles for foundation stabilization it does not offer a solution comparable in performance and should not be used as a substitute.

I came across a new story the other day from KFDX of Texas

We would love to hear from you, click here to comment!

I came across a news story the other day from Fox News KFDX of Texas. I have embedded the link here for viewers to access.

 http://www.texomashomepage.com/story/d/story/heavy-rainfall-causes-foundations-to-crack/33692/wr6SSkOK80Sr7gjdjpDzXA

If you will recall recently Texas has had a lot of rain….. including flooding. The new story deals with the aftermath of that heavy rain. It goes on to state that during the drought Mitchell Armstrong’s house was functioning quite normally. After this year’s heavy rains he noticed his house start to move excessively. As a matter of fact the movement was so great that it shows huge gaps that he is duct taping up on his front door.

Mitchell then goes on to attribute the problem to settlement due to humidity and moisture being absorbed in the wood of his house. The news segment goes on to interview the owner of a local foundation repair company who gives a rather muddled explanation to the phenomenon without really realizing the true cause of the problem.

This is a perfect example of how misdiagnosis happens. Both the homeowner and the contractor do not clearly state the cause of the problem because in my opinion they either don’t understand it or don’t want to understand it. The paradigm of understanding these problems both from homeowners and contractors is that when you have house movement is automatically settlement. Not even giving a second thought to heave. Why is that?

From the homeowners perspective it is perfectly understandable because no one has ever suggested anything different to them. From the contractor’s perspective it is a problem that needs to be rectified. Why does the contractor not understand?

1.       No one has educated him properly about how heave can move foundations and look similar to settlement from a symptom perspective.

2.       He likely is not following any standardized investigation procedures accepted by any engineering consensus.

3.       There is very little likelihood of engineering oversight of his investigation.

4.       He in all likelihood has nothing of value to sell the homeowner to fix the heave problem and so frames his understanding in a way that lets him provide a solution that he can offer.

So here it is another perfect example of what I’ve been talking about for almost two years now.

Why ICC Regulation is having opposite effect of its intended benefit for Foundation Repairs

We would love to hear from you, click here to comment!

There have been four helical manufactures to receive ESR’s for their products. No ESR’s have been issued in the last several years. Is it possible that the remaining manufacturers have realized that the current rules do more to hinder jurisdictional approvals than help?

On Commercial projects there are usually design submittal requirements that require a licensed engineering stamp to be included and there are almost universally soil borings to provide needed data for design. As such the ICC ESR does not provide significant tangible additional benefits as the local jurisdictions rely on the stamp of the local engineer, who almost always insist on boring data as a matter of practice regardless of ICC requirements.

On residential projects, the ICC requirement provides a distinct disadvantage. One of the requirements of all ESR issued products is a soil report with borings on every project. If the Regulating officials read and enforce that requirement in the ESR, then a full geo report is required with borings. On residential projects, this provides little benefit at cost of $3000-$5000 or more. This is required on even the smallest project of a few thousand dollars, providing a disincentive to pull permits or seek jurisdictional approval because of its imbalance in costs and benefits for the homeowner.

On residential projects the governing factor is almost always the span of the footings between the piles as opposed to the weight of the structure. What this means is the factor of safety is usually many times more than the required factor of 2. Even if the piles lock up on a hard lens with soft soil underneath, there is little likelihood of failure because of the large safety factors and lighter loads.

The reality is that although the requirement is that the ICC requires soil borings in all residential applications, it is almost universally ignored, signaling an almost unanimous rejection of it in practice and setting up a de facto alternative. This is a dangerous precedent with unpredictable outcomes and inconsistent enforcement. The opposite of what  ICC intended.

There is a possible alternative. The IRC is intended to provide prescriptive measures in residential applications with a larger FOS to compensate.  I think this qualifies. Rather than requiring soil reports with borings, a standardized prescriptive measure could be prescribed with larger FOS than non-prescriptive applications that could eliminate the need for borings. On new residential construction the same sort of logic is used with a minimum soil bearing capacity without borings.

As in other IRC applications permits and pre-engineered ICC approved products could be required, thus preserving the quality of the products and proper application and installation. Code officials could have a standard that could be uniformly enforced and the industry would more uniformly regulated, providing motivation for the remaining manufacturers to apply for and finish becoming ICC approved, making the foundation repair industry safer and more reliable, utilizing a standard that the industry is more likely to adopt in practice.