How tall should your foundation be?
With more people finding Beaufort in their search for milder temperatures and a less hectic lifestyle, real estate sales and new home construction have remained steady over the last 5-7 years.
All indications are that this trend will continue. Many prospective new residents come from cold, faraway places like New England and the Midwest. Others from nearby North Carolina, Virginia and Georgia seek permanent residence in the Lowcountry after years of visits and vacations.
This column is an opportunity for readers to send in questions about home design, construction and remodeling in Beaufort and the Sea Islands. To submit a question, email email@example.com.
This month’s question examines why houses are built at various heights. Next month’s Q &A will address the pros and cons of a slab foundation vs. floor system.
Houses are seen built at varying heights in Beaufort and the Sea Islands. How is the height of the foundation determined?
In the Lowcountry, flood zones determine how high off the ground a house needs to be built.
In most areas, the base flood elevation is 13 feet. However, this may soon change as some insurance companies are already requiring 14 feet to offer a better rate.
Some examples of different types of foundations include:
• Slab on grade — Concrete poured 6-12 inches above the natural, existing grade is the least expensive and most common height for houses not in a flood zone.
• Raised or elevated slab — A house is built up to 4 feet above the ground using two methods: a poured footer with a block laid to the desired height, then filled with clean fill dirt and a 4-inch slab poured on top; or the concrete is poured into a form for the raised wall using the fill dirt as the inside form. This is commonly called a monolithic slab.
• Continuous block walls are commonly used when a house is to be raised above grade and a crawl space is desired. This will use the block as the foundation and individual block piers under the house as support. Individual communities have guidelines to determine how high a house should be built above grade.
• Houses that are raised up high enough to park under are commonly built with block piers and filled in with some type of lattice to allow air and water to flow through the garage space.
• Driven pylons are 30-80 feet long, 12-16 inches round, pressure treated poles driven into the ground by pounding or vibrating to the specified depth determined by soil tests. These are usually required by structural engineers on Fripp and Harbor islands. This has recently created a problem in terms of new construction scheduling because dock builders who drive the pylons are still backed up rebuilding docks from Hurricane Matthew. This has left the available pool for new construction almost nonexistent.
Other items to keep in mind:
• Flood vents are required in house foundations and garages that are below the area floodplain.
• Build height may be determined by individual communities. They may require a certain height to achieve a particular look. Often, the use of porch piers, in conjunction with a raised slab, can create a desired appearance.
Todd Bradley owns Live Oak Builders, a construction company specializing in traditional Lowcountry style and custom-designed homes. Send your questions about building a home in the Lowcountry to firstname.lastname@example.org.