In certain parts of the US, basements are a ubiquitous component of houses. In other parts of the country, basements are rarely found. This is due to several factors, the most significant of these being moisture in the ground.
While it is possible for houses near the coast to have basements, they are not common in coastal homes. This is due largely to the water table in these areas. If an area has a high water table, it will be difficult to build a basement because the underground water levels are too close to the surface.
Groundwater levels play a huge role in whether it is plausible to build a basement or not, but numerous other factors can also play. It is essential to investigate the ground conditions in a specific area before making an informed decision.
Can You Have a Basement Near The Ocean?
Coastal areas, wetlands, and other areas with a high water table are synonymous with having difficulty when excavating. This is because excavation sites quickly become flooded once the underground water level is reached, and this level is found even higher in coastal areas.
Certain states such as Florida, for example, are synonymous with high levels of underground water and enormous aquifer systems, which pose a major problem for excavation.
Upon digging, water is often found within 6 feet from the surface, and as a result, building sites are very quickly filled up with water. This can pose enormous difficulties for building projects, as the water may have to be pumped out constantly for construction to continue.
Due to the difficulties encountered when building a basement in coastal areas, with the result that special equipment and/or specialized persons have to be brought in, the costs are often too high to justify constructing a basement.
In some cases, it may be impossible or simply infeasible to build a basement due to numerous factors. Soil types and soil conditions can play a major role in this, as can the presence of underground sewage systems, which may be closer to the surface in some areas than in others.
Why Is It Easier to Build a Basement In Some Areas Than In Others?
Upon investigation, one might find that basements are commonplace in some areas of the US, while they are rare in other areas. This is due to numerous factors.
North of the Mason-Dixon line, the percentage of homes built with basements is around 90%. In the south, however, the majority of houses are built without basements.
The biggest contributing factor to this is the levels of moisture in the soil. Southern states such as Florida and Louisiana boast extensive areas of swampland, wetlands, and/or long stretches of coastline.
As a result, these areas have high amounts of water in the ground, thereby making basement construction difficult.
The soil type also makes a significant difference to the feasibility of basement construction, which is not exclusive to areas with extremely moist soil.
Soils that possess higher levels of clay can create major issues with basement construction.
While this soil may not cause flooding, it tends to absorb water during wet periods while drying out completely during dry periods. As a result of this, expansion and contraction occur, which can create major structural problems for any basement construction.
Another factor to consider in the south is the presence of limestone below the surface of the soil. While this is a relatively soft rock compared to other types of bedrock, it can still become a costly exercise to break through it to build a basement. Naturally, the deeper one excavates, the more rock needs to be broken through, and the more expensive the project becomes.
In the colder states further north, the prevalence of basements can often be explained by the colder climate. To avoid cracking and freezing of pipes, building foundations must be constructed below the so-called “frost line.” This line is much lower in colder climates, and so the foundations must be built deeper, making it somewhat logical to create a basement if the foundations are already built to such depth.
How Are Basements Built in Areas with a High Water Table?
Technologies have evolved considerably in recent years, and the development of features such as dehumidifiers, sophisticated sump pumps, and moisture barriers have assisted in the potential to create dry, safe basement environments in most areas of the United States.
While it is inevitable that at a certain depth, the excavation site will begin to fill with water in areas with a high water table, there are ways to work with this to create a safe site. Using a specialized team and special equipment, concrete can be poured essentially underwater, with the water only being removed once construction is complete.
It is, in fact, essential in these cases that the water is left in the excavation pit because without the water in place, a pressure difference would be created between the pit and the surrounding earth, potentially causing the excavation pit to collapse in on itself.
This is especially dangerous if there are any nearby structures, as the foundations of these could begin to crack or slip due to the nearby shifting ground.
The latest developments make use of a secant pile system that is placed in the ground without the need for extreme vibrations or pressure changes. The secant pile system is created by using an auger that rotates through the earth to the required depth.
Once at the correct depth, concrete is pumped through the auger until a pile is created, and when the piles have cured, the soil is removed while leaving the natural groundwater in place.
A concrete slab is poured below the water, preventing any new water from entering the site.
The water the slab has sealed in is pumped out, and the construction can begin on the basement itself.
What Alternatives Are There to Having a Basement?
In the absence of a basement, many houses in the south have used their attic space as an alternative storage space, laundry, or – in many cases – an entertainment area. Attic spaces also give the benefit of natural lighting, which is often not present in basements.
Outdoor garden sheds are another relatively inexpensive alternative to a basement, where the purpose of a basement, in this case, would have been purely for storage.
In conclusion, while it is possible to build a basement in a coastal region, it is often not plausible or simply too expensive. Before deciding to build a basement on the coast, one must embark on thorough research to establish whether it will be feasible or not.