What is a foundation survey?
If you are buying a new home or building a custom home, then you should have a foundation survey completed. A foundation survey is not the civil survey you get when buying or selling a home. A foundation survey is a document that shows a schematic floor plan of your house with elevation readings throughout. The elevation readings represent the high and low points of your foundation at the time the readings are taken. Consider it a snapshot of the current position of the foundation. The initial foundation survey establishes a baseline of the foundation's contour.
Why do I need a foundation survey?
If you are buying a new home or having a custom home built, the initial benefit of a foundation survey is that the document becomes a recorded, independent record showing the elevation readings of your foundation at a point in time (date of measurement). The document can be referenced later if you ever suspect the foundation may be moving or has foundation-related problems. If you suspect the foundation is moving, another foundation survey can be completed, and the elevation readings can be compared to provide you (or a structural engineer) with information on the degree, location, and relative rate of movement. For example, you purchase your dream custom home tomorrow, and today you had A-1 Engineering provide you with a foundation survey. The survey would show your floor plan with spot elevations throughout. Three years from now, we have a severe drought, and you begin to see cracks throughout the building. Obviously, you become concerned with whether you have foundation problems. Since you have acquired a foundation survey taken today, we will remeasure the foundation three years from now and compare the elevation readings to better understand the extent of movement and determine where it is occurring. This information may indicate plumbing leaks or movement caused by other sources, such as trees, drains, irrigation systems, settlement, or septic systems. This information becomes invaluable when deciding whether to have the foundation of your custom home “repaired” or “leveled”.
Who needs a foundation survey?
Any homeowner who is proactive in monitoring the performance of their foundation or a homeowner who recently purchased a home. Consider the following scenarios:
Scenario #1: One year ago you watched the construction of your custom-built home, and now you notice cracks throughout one wing of the house. Just before the flooring material (carpet, tile, laminate, etc.) was placed, you had a foundation survey completed for the entire floor plan. Now that you suspect possible foundation movement, you have another survey completed. The data from the first and latest surveys are compared, indicating the corner of the master bedroom has dropped 1.25 inches. You call the builder, and he says his warranty coverage takes effect if the movement exceeds 1.0 inch. If you had not taken the initial survey, then the builder can claim that the foundation started 0.5 inches low; hence, the builder is claiming that the foundation only moved 0.75 inches (1.25” – 0.5”), and the warranty will not cover the damages. Without your initial survey taken a year ago, you have no data to counter the builder’s assumption. However, since you proactively had a foundation survey completed, the data clearly show that the elevation difference between then and now exceeds the 1.0-inch criterion. Keep in mind that the one-inch warranty clause is used in this scenario to illustrate a point and does not imply that all home builders have similar clauses or offer a warranty.
Scenario #2: You purchased your home five years ago; now you see cracks within one of the walls of the main corridor. You call a foundation repair company to get a quote for possible foundation repairs. The four contractors that you call tell you that the foundation has dropped 2 inches across the front of the house as a result of the drought, and this drop is what caused the damage. They recommend a foundation repair costing $10,000 to bring the foundation back to where it started. You go to your file cabinet and pull out the foundation survey that was completed just before you first moved in. According to the survey, the front wall was already 1.5 inches low when you first bought the house, and it did not have all the cracks that are now showing up. Instead of agreeing on foundation repair, you have another foundation survey completed, and the data indicate that the restroom near the corridor is 0.5 inches higher. Without the initial foundation survey, the current elevation readings suggest a two-inch drop, but according to the data, the foundation has only moved 0.5 inches (keep in mind that the foundation was already 1.5 inches low when you moved in). The higher elevation reading in the restroom may have been due to a plumbing leak. Relating the soil movement (damage to the wall) to the plumbing leak provides a more viable explanation (supported by historical data) than simply accepting that “the drought” caused the damage.
Scenario #3: You purchased your home 15 years ago, and this past summer you began noticing cracks at the edges and joints of your newly remodeled kitchen. Suspecting the worst, you call a foundation repair company to provide you with a cost estimate and recommendations for foundation repair. The contractor states that you need 30 piers at a cost of $15k because your foundation has tilted, causing the damage. Again, you pull the foundation survey completed 15 years ago from your file cabinet and get a current one. The data from the two surveys are compared, and they are relatively similar, suggesting the foundation has always been tilted and has moved very little. Since the foundation surveys do not indicate significant movement, you save the $15k on foundation repairs and have the cracks assessed.
Are foundations constructed level?
Concrete contractors and custom home builders certainly try hard to construct a level foundation. The tile contractor and the framing contractor appreciate a level foundation. However, constructing a perfectly level foundation using common industry practices is not easily possible. As an analogy, consider the task of icing a square flat cake. The icing may be pasty enough for a smooth finish, but because the icing knife is hard to control, the finish will have slight highs and lows. You may not be able to see the difference, but they are there. That same phenomenon occurs with the construction of concrete foundations. Concrete foundations may have differences of up to ¾” to 1” from one side to the other (high or low). Once the concrete foundation is constructed, it is not feasible to remove it and start over. Having a foundation survey once the foundation is constructed will give you an idea of where the highs and lows are. This information is valuable in monitoring the performance of a foundation. Consider the foundation survey as a baseline of where your foundation starts.
I am buying a home, should I have the foundation completed before or after I move in?
If you are considering buying a home, then we recommend getting a general (Level A) structural assessment after the home inspector has completed their inspection. The structural assessment should include the roof framing and the overall building condition. Buying a home with broken or overstressed roof members may cause ceiling cracks that may later be mistaken for foundation problems. The structural engineer should take elevation readings to get a general idea of the foundation's slope relative to any visible cracks. His assessment should comment on the general levelness of the foundation. If you decide to buy the home, then you should ask the structural engineer to complete a foundation survey of the whole house prior to moving in. This will allow the engineer to have greater access to the entire house for additional elevation readings.
How often should I get a foundation survey after buying or building a home?
Obviously, the first foundation survey should be completed prior to moving in, regardless of whether you buy a new home or have a custom home built. If you build a custom home, we recommend that a foundation survey be completed every 3 years after construction for the first 12 years, and then as needed. This monitoring sequence allows the soils to undergo 12 climatic seasons between foundation surveys. The three-year interval (12 climatic seasons) assumes that the foundation will experience one very rainy year, one drought year, and one normal year. Problems with the foundation's performance are more likely to be identified early.
If you are buying a home, the sequence for monitoring foundation performance depends on the foundation's age. If you buy a fairly new custom-built home (5 years or less), the previously mentioned 3-year interval is recommended. If the home is older, we recommend consulting a structural engineer to help you plan the sequence of foundation surveys to monitor its performance.
Regardless of whether you buy a new home or build a custom home, we recommend a foundation survey if you suspect foundation movement. Some cracks are misinterpreted as caused by foundation movement, and homeowners are convinced to “repair” a foundation that has moved very little (and is performing relatively well). The foundation survey for new home buyers is the most valuable document to monitor and detect possible foundation problems.
What would Confucius say about a foundation survey?
“It is better to have the information and not need it, than need the information and not have it”.
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