Sinkholes never happen at the right time as demonstrated by the sheer force of Mother Nature that destroyed 2 homes this past weekend in Land O’Lakes, Florida and forced the evacuation of 5 mandatory and 12 voluntary surrounding homes as a precautionary measure. And demonstrated by the magnitude of this situation, it also has brought our company into the conversation. We at Helicon pride ourselves on our company values and one of them is “Communicate Clearly.” We believe it is important to make a statement to clear up some of what is being miscommunicated, misinterpreted, or reported by the media to provide clarity on the situation.
The home at 21835 Ocean Pines Drive, Land O Lakes, FL 34639 had a subsidence investigation report carried out by MCD of Central Florida prepared for American Mercury Insurance Company in May of 2012. In this report, it stated “It is impossible to predict whether or not the identified sinkhole activity will continue to progress resulting in additional settlement damage. If preventative measures are implemented in an effort to minimize future potential settlement of the structure, a program of shallow and deep grouting, detailed in the following sections of this report, would be an appropriate method. A commonly used and effective remedial measure to stabilize subsurface soils typically involves completing of a subsurface grouting program. The intent of the subsurface grouting is to seal off the limestone surface, fill voids, and determine any loose or soft soils above the limestone/soil interface. This is accomplished by injecting low mobile, grout (typically 5-inches of slump) through 2 to 3-inch diameter steel pipes spaced at intervals approximately 8 to 10-feet around the perimeter of the structure and screen porch. The grout is injected at high pressures, beginning at the very dense soils and continuing up as a grout pipes are withdrawn. We estimate 34 grout injection locations installed to depths between approximately 45 and 60 feet bgs. We estimate 200 to 300 yards of grout.…Because of the presence of loose bearing soils, a program of shallow permeation or chemical grouting is recommended. Shallow injection locations should be completed an approximate 5-foot centers around the perimeter of the main structure, lanai, screen porch, and covered porch as well as the north and east interior walls of the garage. We estimate approximately 2,800 to 4,000 pounds of shallow grout material (estimate based on the use of urethane type of foam). Cost for both the deep and shallow grouting programs arrest which range from $105,000 to $149,500.”
The homeowner did not go through with MCD of Central Florida’s original recommended plan and opted to have another plan made 2 years later with an independent engineer, who the homeowner hired to put together an alternative plan. In a plan recommended by Basic Engineering and after reviewing the opinions and the initial report by MCD of Central Florida, work began shortly after. This alternative plan, which was elected by the homeowner, suggested the use of underpins to stabilize the foundation perimeter only. “Pressure pin piles in the areas marked on the attached engineering drawings have been recommended. The pin piles should be installed with hydraulics, which transfers the load of the structures through the problematic soils onto a load bearing stratum. The pin pile shall be end bearing on competent rock only and shall not be stopped in skin friction bearing material. Should the pin piles be stopped prior to reaching competent rock, the pin piles shall be drilled and/or sleeved….The elevation of the structure should be monitored continuously during the pinning process to minimize unnecessary upward movement and to avoid additional damage….in order to support the foundation, installation of pin piles (the “underpins“) is recommended)….A foundation bracket will be installed at each underpin location in accordance with the attached pin location plan. The pressure and depth reading should be required for each of the underpins.”
(Illustration of underpins being installed to load bearing stratum around the perimeter of the foundation)
Apparently, the homeowner chose not to have the more expensive process completed and went with the recommendation of the second engineer. “I can’t speak for the homeowner, but it may have been that the original grouting repairs were more than they could afford and felt that underpinning around the perimeter of the foundation is better than doing nothing,” said Jay Silver President of Helicon. Underpinning can run between $20,000 and $50,000, while compaction grouting and chemical grout, the process of hardening the soil closer to the surface, can run between $70,000 and $100,000, or even more. Engineers can only guess how much grout might be needed to pump into the ground, but if they’re off, the homeowner may be on the hook for tens of thousands of dollars more. Even homeowners who have sinkhole insurance are often forced to settle with the insurance company for a set amount of money, leaving them to make up the difference if the repairs cost more.
A past customer of Helicon has said, “many times the price for the grouting type “fix” exceeds the value of the house. Then if the insurance company will only pay out enough to underpin (the cheap “fix”) the homeowner doesn’t really have much much choice as the resale value of their property has already taken a 70-80% hit. Very often, the homeowner still owes more on the house than they could ever hope to recover, so do you what you can and trust the Lord for the rest!”
We were contracted to install underpins at the home per the engineer’s plans. “This is just a pure structural stabilization for the foundation but is not a sinkhole repair,” said Helicon President Jay Silver. “Underpinning is a repair method used to fix sinkhole damaged structures. It utilizes underground steel piers to stabilize the foundation.”
(Illustration of the compaction grouting process stabilizing subsurface soils)
Over the course of 6 days, a total of 33 pressure pins were installed demonstrated by the final engineering report made by Basic Engineering. “As requested, we have completed the monitoring of the subsurface pressure pin piles insulation as contacted by Helicon Property Restoration, Inc. (HPR). This work was completed utilizing the TMG Pin Pile and Bracket Systems. The remediation was started on October 9th, 2014 and complete October 15th, 2014. A technician from our firm was present during the remediation to monitor the operation. HPR installed a total of 33 pressure pin piles around the property as per our site plan recommendations). The depths of installation ranged from a low of 38 feet to a high of 59 feet below grade. Each pin pile was hydraulically driven into the soil until enough pressure was reached for refusal. The hydraulic gauge reading (psi) was required for each pin pile along with the installed depth. It is our opinion that the pressure pin piles were installed in accordance with industry standards. The proven technology utilized by the pier manufacturer and the ability to solve foundation settlement problems using a pressure pin piles, has demonstrated success without additional settlement. This report is a summary and certification of the work completed by Helicon Property Restoration.”
Unfortunately, some of the misinterpretation stems from the “Remediation Activities Summary Report” filed with the Pasco County Clerk of Court after the project was completed being mislabeled as compaction grouting which is incorrect as the final engineering report and description of services clearly indicate underpinning which we were contracted for and carried out. Also, the property appraiser website listing the home as “Sinkhole Activity Stabilized” is very misleading as well.
After completing thousands of geotech construction jobs in the state of Florida, the final engineer report was shared with the Pasco County Clerk of Court which was labeled as sinkhole remediation. Helicon is a firm proponent and as a leading member in FAS³ has been advocating for changes in legislation. FAS³ is an association of engineers, geologists, contractors and suppliers concerned with the ethical investigation, planning, design and remediation of sinkholes and sinkhole damaged properties.
FAS³ was formed in 2006 to:
· Set standards for conduct, workmanship and business practices for those involved in the profession.
· Improve and develop knowledge of new ideas and methodologies of subsurface grouting, foundation stabilization, and related testing and to share that knowledge with other professionals and interested parties.
· Improve the understanding of sinkhole formation, investigation, evaluation, and remediation by educating the public, government bodies and other interested parties.
· Encourage, fund, and participate in the practical application of research related to subsurface grouting, underpinning and foundation stabilization work, including providing educational opportunities for members of the organization, governmental officials, and the general public.
We have worked closely with legislators at the local and state level to clearly define these types of services and how they are being categorized and reported in addition to lobbying for insurance companies to follow through on sinkhole jobs rather than paying out the policy holder. It is in our expert opinion, that local counties should not label certain jobs as sinkhole remediation and to clearly define remediation as either sinkhole or structural remediation. The process of underpinning is not a sinkhole remediation but will stabilize the perimeter of the structure and not center on grade as reported by several news outlets that Helicon provided sinkhole repair on the property. It was, in fact, structural repair. Larry Madrid, of Madrid Engineering, mentioned, “I saw a photo that showed underpins under the (former) house. Underpins may support structure (evidently not enough in this case!), but do not remediate a sinkhole! A sinkhole by definition are voids and cavities in the limestone, and to remediate that you must backfill those voids and cavities with pressure grout. That’s the only way you can prevent it from collapsing again. One of the houses in question did not follow insurance company’s engineering recommendations to grout the subsurface; they evidently got a cheaper fix and kept some of the insurance money for themselves.”
(Our underpins that were installed in 2014 are still standing in place after the sinkhole consumed the home from the center on grade)
As a company, our hearts empathize with those impacted by the events of this past weekend and will work closely with engineers and county officials to remediate the area and continue to provide assistance to make the area safe. We will also continue with our industry peers to advocate for adequate legislation at the local and state level to better support property owners faced with the potential for similar situations.
Helicon is the premier geotech construction company in Florida. Based out of Tampa, FL. we are a licensed general contractor leading the industry in full-service geotech construction work.
We are experts in pre-construction, soil and structural stabilization, & sinkhole repair. As the premier provider of geotech construction services throughout the state of Florida for nearly 15 years, Helicon prides itself on providing high-quality service, for both insurance companies and private customers with handling all repairs and pre-construction work for both residential and commercial projects. We strive to exceed everyone’s expectations.
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