Beachfront homes have specific requirements in terms of many aspects of their construction. This includes the physical building materials as well as other aspects of construction such as walls and foundations. This is due to the climatic conditions associated with the coast.
Beachfront houses are best served by making use of pier and beam foundations or pile foundations. This is due to the ability of these foundations to withstand harsh coastal conditions, as well as to be able to create stability in unstable soil conditions such as sandy areas.
There are numerous factors to consider in making a choice for your house foundations. There are also several different types of foundations, and each of these is best for a different type of situation.
What Type of Foundation is Best for a Beachfront House?
Due to the sandy environments found in coastal areas, certain foundation types are better equipped to withstand these conditions than others.
In addition to the structural benefits, making use of pier or pile foundations afford the possibility of enhanced views for the house as well as breezes. This is due to the elevated position afforded by this type of foundation system.
Pier & Beam
Pier and beam foundations are considered to be the best option for a beachfront house. Beachfront areas are synonymous with unstable, sandy soil conditions, and pier and beam foundations are best able to withstand these types of conditions.
Pier foundations provide a robust and safe structure that can easily be adapted to a variety of difficult land situations.
Also known as post and pier foundations, this structure makes use of square or circular pads of concrete placed at strategic spots around the structure of the building itself. The footing pads are dug deep into the soil and usually set on a stable underground feature such as bedrock.
Once the concrete footing pads are placed, timber columns are attached to the footings. These columns, in turn, are connected to one another through the use of girders. These girders are horizontal timber (or steel) beams that support the structure of the building above.
This type of foundation is ideal for a beachfront area due to its ability to endure shifting grounds and loose soil which are highly prevalent in sandy beach areas.
Pile Foundations
Pile foundations are another good option for a beachfront home foundation. These consist of individual supports which are driven deep into the ground until they reach a stable support layer of bedrock.
This allows the house to withstand any flooding and storms and grants it the ability to provide a stable support system in less-than-ideal soil conditions such as sandy coastal areas.
Pile foundations allow homes to be constructed in a way that floodwaters are unable to reach the home and therefore cause damage to the building structure.
Pilings are set into the ground by injecting water into the ground, and these are held in place through the pressure of the surrounding sand.
8” by 8” pilings are placed at a minimum of 8 feet underground, or 16 feet underground when it comes to buildings closer to the ocean.
Another advantage of homes built on piles is their ability to be moved due to issues of settling or erosion. This moving can happen relatively easily, and these homes can be raised up or reset when and if necessary. There is even the option to load the home onto a truck and move it to a different location if this ever becomes necessary.
Types of Pilings
Timber pilings have been used for a number of years in coastal building projects. They are ideal for wet climates and loose soil compositions. Most building codes require buildings in flood zones such as coastal areas to be elevated above the floor level.
Due to the exposure to harsh conditions and the reliance on a stable foundation to keep the building intact, the pilings become the most structurally important aspect of the construction project.
Despite their numerous benefits, pile foundations have a tendency to be more expensive and take far longer to build than standard foundations.
There are numerous types of pilings that are used in coastal construction projects, and whether these are made of concrete or timber, there are advantages and disadvantages to each type.
Square and round pilings of timber (Southern yellow pine) have excellent properties when it comes to strength versus cost. This type of timber is also able to accept multiple types of treatments, giving it good versatility.
Polymer coated pilings are usually timber pilings that are coated in a protective polymer membrane that bonds to the wood. This polymer membrane prevents destruction which would otherwise be caused by wood borers, dry rot, and termites. The polymer coating also resists damaging UV rays as well as the negative effects of freezing.
Gun barrel pilings are usually solid pilings with a uniform diameter throughout their length. The advantage of this type of piling is how it combines the strength of regular round pilings with the uniform nature of square pilings.
When it comes to water, gun barrel pilings are ideal because water is able to move more quickly and smoothly around the pilings, having very little negative impact on the structure.
Another advantage of the gun barrel piling is its ability to prevent attacks from marine borers and termites. This is due to the lack of exposed heartwood when compared with square pilings.
Why Does a Beach House Need a Stronger Foundation?
While in a normal residential area, typical foundation systems are perfectly adequate for most buildings. With a waterfront property, however, there are numerous issues such as heavy winds, bad soil conditions, and floodwaters.
The above harsh conditions can cause difficulties in creating long-lasting foundation systems.
Sandy ground is often subject to erosion. The land beneath the foundations may be gradually removed, causing the building to collapse.
Due to this, normal slab construction is prohibited in coastal areas for the majority of building codes. This is because this type of foundation has a larger surface area which would be exposed to sea swells rushing up against the house.
The greater the surface area of the foundation which comes into contact with the water, the greater the danger of the structure collapsing. Therefore, as a result, homes on the coast usually require an open foundation system that allows water to flow between the elements of the structure.
There is also usually a minimum height requirement for the main deck of the house, ensuring that floodwaters are unable to reach the main area of the house while allowing floodwaters to flow safely underneath the house.
Types of Foundations
There are many different foundation types that are best suited to different environments and types of structures. While some of these are not suitable for use in coastal areas, it is important to know how they function and how they differ from one another.
Basement Foundation
Basement foundations are popular in the US due to their structural stability as well as their potential to create extra space within the home to be enjoyed by its users.
This type of foundation, however, is less popular in coastal regions because it is mostly impractical in these contexts due to high water tables, etc.
Basements are mostly found in the Northeastern and Midwestern areas of the US where the soil is able to support the structural components of this type of foundation.
In order to create a basement, a hole has to be created which is at least 8 feet deep. This foundation type is created through the use of footings that are placed below the depth of the frost levels, solid concrete walls, and a solid concrete floor slab. This creates a secure, stable structure that will support the rest of the building above.
Basements are often built by default because foundation footings have to be built to a certain depth in certain regions, which makes the construction of a basement an easy addition to create.
Crawl Space Foundation
A crawl space is not dissimilar to a basement, however, it allows the main structure of the building to be kept above the ground level. Concrete footings and short foundation walls are poured which creates just enough space to access plumbing equipment in the event that repairs are needed.
The space between the house’s floor structure and the foundation is referred to as the crawl space, and this is literally an area around 20 inches high which allows space for the plumbing and HVAC equipment to be kept.
Slab Foundations
When land is stable and relatively flat, slab foundations are usually the ideal choice. This foundation type consists of a flat concrete slab of 4 to 6 inches which is poured over a bed of gravel or small stones. Perimeter footings and interior support footings are poured as support for walls or columns.
This foundation type is usually lower in cost than a basement foundation while remaining relatively easy to construct. Plumbing systems can be buried underneath the slab, however, this creates potential difficulties in the event that repairs are needed.
Factors Affecting Depth of Foundation
The depth of the foundation is affected mostly by the bearing capacity of the soil. How capable the soil is of bearing the weight of the proposed structure will determine whether improvements have to be made to the soil, or whether foundations will need to be created deeper to compensate for the lack of soil stability.
Pile foundations, for example, must be driven as deep as necessary to reach a solid bedrock surface, as the sandy soil will not afford any stability for the foundations.
What To Consider When Choosing a Foundation?
It is extremely important to ensure that the type of foundation chosen is one that is best able to support the type of structure being built.
The foundation of the house needs to support the entire load of the house above it. Depending on the weight of the house, as well as its size and the type of house, different foundation types will perform differently.
An architect or structural engineer may design a specific type of foundation for your house. It is not at all advisable to deviate from this initial design in any way without consulting with the relevant building professionals.
There is always a reason that this type of foundation was initially chosen, and any deviation may have extremely detrimental ramifications for the entire structure, potentially causing collapse and other structural damage.
The soil is naturally another major consideration when looking at foundation choice. The soil in question must be fully settled and undisturbed. If this is not the case, shifts in support for the foundation structure may occur which may cause a complete breakdown of the structure.
In order to determine whether the soil conditions are suitable, a professional should be brought in to perform the relevant tests before any digging or foundation installation can occur.
Dryness of the foundation is another important factor to consider. Groundwater can potentially become an issue, and this is especially problematic and prevalent in coastal areas where the groundwater is particularly high.
Damp foundations are never good foundations, and this is especially true for deep basement foundations. Usually, a percolation test should be performed on the soil before commencing construction on a house. This will ensure that the soil will be able to percolate water properly for the purposes of a septic system.
If the soil is able to pass a percolation test, this means that groundwater should not become an issue when it comes to the foundations.
A properly performed soil test will determine what type of soil is present, and resultantly will determine the moisture content as well as the compaction qualities of this soil type. This test will ensure that the foundation is able to perform properly at all times.
It is important to always attempt to redirect water away from the building foundations whenever possible, especially when it comes to basement foundations. Drainage materials such as gravel and sand can assist in protecting the foundations from any major moisture issues, as can a sub-slab drainage pad.
Conclusion
Beachfront houses have unique needs in terms of their structure, and so it is extremely important that their foundations are carefully considered to suit their specific environment. This will ensure a safe, well-performing, and enjoyable structure.
Sources
- https://www.coastalhomeplans.com/ten-tips-building-coast/
- https://theconstructor.org/question/which-type-of-foundation-should-be-used-in-coastal-area-and-sloping-ground/
- https://www.newhomesource.com/learn/house-foundations-difficult-terrain/
- https://www.theplancollection.com/house-plan-related-articles/tips-for-choosing-the-best-foundation-for-your-new-house-plan
- https://www.paynebuildingmovers.com/articles/why-a-beach-house-needs-a-stronger-foundation/
- https://www.grayberryman.com/wp-content/uploads/2018/06/Gray_Newsletter_008.pdf
- https://buildingproductsplus.com/beach-home-materials/
