Modular Homes Section

Soil Expert Talks About New Home Construction

Bob Eppinette
Soil Scientist
Lowcountry Soil Consulting, LLC
September 2011

Modular Today was fortunate enough to talk with Mr. Eppinette in between his soil analyst projects. We typically do not think about the soil and just think dirt is all the same. Lucky for us Mr. Eppinette shares his soil wisdom and explains why you should never take soil for granted especially when that soil is supporting your home's foundation.

Modular Today: How did you become involved in soil consulting?
Bob Eppinette : I spent my professional career working as a soil scientist with the United States Department of Agriculture - Natural Resources Conservation Service (33 years). I started my soil consulting business in 1998 as a sideline business. I work mostly with developers, engineers and individual property owners or buyers. Mainly, my clients need to know if there are wetlands on a property or if a property will "perk" for a septic system. My work involves just about anything dealing with the soil.

Modular Today: Why do new home buyers need to be concerned about soil?
Bob Eppinette : New home buyers should be concerned about the soil at the very beginning of the house buying process. It is a lot less costly to get the right piece of land with no or few soil limitations before any contract is signed or any house is planned or designed.

The two main concerns in the Lowcountry area of South Carolina are wetlands and suitability for septic systems. Avoiding wetland impacts can save property buyers thousands of dollars in wetland permitting and mitigation.

Knowing if the property can be permitted for a standard or engineered septic systems is a major concern in areas without public sewer. Standard septic systems can cost anywhere from $2,500.00 to $6,500.00 depending on soil water tables, soil textures and the number of bedrooms. Engineered septic systems can cost $15,000.00 to $30,000.00 and higher.

Modular Today: Do consumers who plan to use municipal water & sewers need to worry about the soil?
Bob Eppinette : Yes! They should always do their homework when sinking a lot of money in a property. Check to see if the soil has flooding or ponding problems. FEMA flood maps are a good start, but they only address flooding not ponding. County Soil Surveys published by the Natural Resources Conservation Service are also good guides, but they are not site specific.

It is always a good idea to have a licensed soil professional do a soil/site analysis on any lot or acreage before you buy. It may cost a few hundred dollars for this service, but it is well worth the money to avoid any costly engineering or other problems later.

Modular Today: What soil analysis should be done when new home buyers pick a building site?
Bob Eppinette : As mentioned above, check for wetlands, check soil suitability if using a septic system, and check for flooding or ponding problems. There can be other soil limitations such as: high shrink-swell clays that cause foundation failure; areas that have been filled in with unsuitable soils, building materials or organic debris - even hazardous materials; shallow limestone areas which are subject to sinkholes; soils prone to landslides; soils with possible high radon levels; soils with wetness problems which can cause mold and rot; soil erosion on steep slopes can be an ongoing problem if not dealt with properly; some soils are highly corrosive and can eat away at metals.

The location of the building site in the watershed can be crucial because the natural flow of runoff has been radically altered in some areas by intense development. This will become more of a problem in the future and can cause flooding in areas that are not in a natural flood zone. Also, an analysis of the drainage system in an area should be done to see if it is properly maintained by the city or county. Ask people living in the area if there is any drainage or flooding issue. Many homes have been flooded due to poor maintenance of ditches and storm water systems and they were nowhere near a flood zone.

Modular Today: What common mistakes do new home buyers make?
Bob Eppinette : Home buyers are mainly concerned about the final cost. They spend most of their effort in designing the new house to suit their wants and needs. However, with all the things to think about in designing a new house - soils are given little or no thought at all.

The biggest mistakes I see in the area I serve is that new home buyers purchase a lot or acreage (sometimes at a cheap price) and end up spending thousands of dollars to overcome soil limitations. It would have been much less expensive to buy property that doesn't have these problems.

Modular Today: What questions should new home buyers ask their builder?
Bob Eppinette : Is the house sited properly? Make sure all water drains away from the house. Is the right kind of foundation being used - crawl space vs slab? Does the property have wetness problems? If so, then the builder needs to bring in suitable fill material to elevate the house. Ask the builder about the drainage system in the area. Where does all the runoff go?

Modular Today: What advice would you give to consumers who are about to start foundation work?
Bob Eppinette : The main advice I give my clients before they build a new house is to make sure they bring in 1 to 2 feet of good fill material to elevate the house so water is directed away from the foundation. A good sand fill will help alleviate any wetness or moisture problems around and under the foundation. Be sure to muck out all topsoil and organic materials where the foundation will go. Organic materials tend to hold moisture and have poor load bearing characteristics.

If consumers build in an area with high shrink-swell clays, then a properly designed foundation is a must. I would think building codes in areas with that type of clay probably already exists.

Modular Today: How does technology help you with your soil analysis?
Bob Eppinette : I use GPS and GIS in most of my soil reports. The hand held GPS receivers are becoming more accurate and the GIS systems are becoming easier to use.

I don't think anything will ever replace the trusty ole hand auger and a knowledgeable soils person on the other end. All of my projects are the "hands on" get dirty kind. Technology is great, but it has its limitations too.

Modular Today: Have you ever been surprised with the results that your work uncovers?
Bob Eppinette : I can distinctly remember a time when I was checking the soils on a site to determine the presence of wetland. As I was boring the hole, I smelled the very strong odor of some type of fuel. It was my opinion that the fuel from fuel tanks at a nearby air base/airport was leaking into the ground water.

There was also a project on an old phosphate mining operation where some kind of chemical was used to separate the phosphate. This chemical odor (even after the operation was closed nearly a hundred years ago) was still present in the soil.

Modular Today: What costly mistake(s) have you come across?
Bob Eppinette : People buying property they never should have bought. Land can have a Jekyll/Hyde effect. You can walk the property in the summer when it is dry and the property looks well drained. Then, you can come back in the winter and it may have water on the surface. The depth of seasonal soil water tables can fluctuate several feet over several months.

The most costly factor I encounter quite often is someone having to install an engineered septic system Some times these systems cost more than the property. This is when I tell my clients to go buy a better piece of land because the economics doesn't make sense to install a septic system that cost as much as the property.

I have a quotation on my website about buying a "pig in a polk". The most important advice I can give someone is to have a licensed, insured professional soil scientist perform a soil/site evaluation before they buy property. Some states have licensing programs for this profession and licensees are listed on rosters on the state's website.

Bob Eppinette can be contacted at Lowcountry Soil Consulting