At Sea Level: Architecture in the Lowcountry
Hello, readers! Welcome to the Architecture Plus blog! We provide useful information concerning architectural design, unique trends, and essential aspects of the residential and commercial building process. Based out of Charleston, our full-service firm specializes in new residential construction, renovation, and commercial design. We aim to create sustainable structures which facilitate the health of their inhabitants while pairing harmoniously with their surrounding community. We encourage you to take a look at our residential and commercial galleries to glimpse our work and assess our artistic vision. If you need any additional information, reach out to us! We are members of the Better Business Bureau, the American Institute of Architects, the National Association of Home Builders, the Royal Institute of British Architects, and are licensed in South Carolina, North Carolina, as well as several other states. The members of our firm hold over sixty years of combined experience and are dedicated to continued excellence. You can contact us through our website or by calling (843) 718-3416.
Our last article tackled the fundamental differences between designing for commercial builds and residential builds. While residential builds can vary according to their scope and layout, they serve a primary purpose–that is to act as a residence. Commercial buildings, on the other hand, can (and often do) serve a variety of purposes. Commercial buildings are held to a different standard than residential buildings and, as such, certain considerations are necessarily undertaken during the design process to ensure all of these qualifications are met. We defined what exactly commercial architecture is, before delving into the architect’s role in designing commercial projects. We left off with a few important considerations to take into account when designing commercial architecture—such as scale, budget, requirements, and classification. We hope to expand our resources on commercial architecture, but if you’d like to learn more about the basics, our last article is a good place to start!
Today, we’re exploring the architectural features of residential and commercial buildings in the Lowcountry. Specifically, those design elements which have been included for the purpose of mitigating flood risk. The Lowcountry is called the lowcountry for a reason. At an elevation of a mere thirteen feet, the Lowcountry is poised at about sea level. Several rivers and waterways–such as the Stono, Ashley, Cooper, and Wando rivers–pose a significant flood risk. The Federal Emergency Management Agency (FEMA) has several designations for flood zones, with Zones A and V considered “high hazard flood zones” and Zones X and D considered to be outside of the Special Flood Hazard Area (SFHA). Much of Charleston County consists of the AE flood zone, which is defined by FEMA as “areas that present a 1% annual chance of flooding(opens in new window) and a 26% chance over the life of a 30-year mortgage.” The coastal areas of Charleston–riverfront and beachfront–fall under the VE flood zone, which is defined by FEMA as having a “1% or greater chance of flooding and an additional hazard
associated with storm waves. These areas have a 26% chance of flooding over the life of
a 30‐year mortgage.” The inland portion of the Lowcountry mostly falls under the X flood zone, which is defined by FEMA as an “[area] of moderate flood hazard, usually the area between the limits of the 100‐year and 500‐year floods… Zone X is the area determined to be outside the 500‐year flood and protected by levees from 100‐year flood.”
Such high exposure to flooding means homes and businesses within the Lowcountry need flood insurance and are likely to pay higher premiums for said insurance. This also means homes and businesses need to be designed and built with such risk in mind. Today, we’ll take a look at those regulations which are stipulated by local housing authorities in the Lowcountry to make residential and commercial properties safe from flood risk. If you’re more interested in reading about Charleston’s architecture in a general sense, we recommend giving our Celebrating Charleston Architecture article a read! If you’re interested in learning about how architecture makes homes and businesses in the Lowcountry safer, then you’re in the right place!
Grade Level
Elevation is considered to be the best method of flood protection. For this reason, it’s usually required for homes within flood zones to be elevated above grade level. Grade level, or grade elevation, is defined by FEMA as “the lowest or highest finished ground level that is immediately adjacent to the walls of the building. Use natural (pre-construction), ground level, if available, for Zone AO and Zone A (without BFE).” In Charleston, in V Zones, this elevation is measured using the “bottom of [the]lowest horizontal structural member,” while in A Zones this elevation is measured using “the top of [the] lowest floor.” In non-residential buildings, dry floodproofing to the minimum elevation is allowed. Dry floodproofing is defined by FEMA as “measures that make a structure watertight below the level that needs flood protection to prevent floodwaters from entering.”
New construction residential homes must be built to minimum flood protection elevations (FPE) if they are located within the flood zone. In Charleston, this minimum requirement is set at two feet above grade level.
Methods of Elevation
The method of elevation used is dependent upon the quantity of elevation necessary and whether the building is new construction or in need of improvement. If a home is being built in an X Zone and the risk of flooding is low, the elevation required can easily be achieved through the right choice of foundation. A new block, helical, or pier foundation can provide an adequate basis for the home to fulfill its flood zone requirements. If a home has already been built in an X Zone but, due to shifting zoning designations (which FEMA updated at the start of 2021) is now part of the AE Zone, raising the foundation might still be possible. The home can be lifted and the existing foundation extended. If a home is being built in a V Zone, then a piling foundation is usually required. These deep-rooted piles effectively anchor and lift homes that are exposed to a higher risk of storm surge, wind, high tide, waves, and flooding. Pilings can be made from timber, steel, or reinforced concrete.
Certification
Looking to build or renovate within a flood zone requires multiple certifications and permits. For example, you’ll need an elevation certification. An elevation certification is necessary for obtaining flood insurance, as well. To complete the elevation certificate, you’ll be asked to provide information such as:
The square footage of crawlspace or enclosure(s).
The number of permanent flood openings in the crawlspace or enclosure(s).
The height of the top of the bottom floor (including basement, crawlspace, or enclosure).
The height of the attached garage.
The height of the platform of machinery and/or equipment servicing the building.
Much of the information provided on the certificate will need to be signed off by a land surveyor, engineer, or architect. The most common reasons elevation certificates require correction are: 1) the certificate isn’t the most recent edition, 2) Field A8d or Field A9d is marked “YES” but the ICC-ES Report or the Certification of Engineered Flood Openings isn’t attached, 3) Field B1 reads “Charleston” but doesn’t also read “455412,” 4) the certificate is for Charleston County but Field B7 doesn’t read “1-29-2021” or is for Berkeley County but doesn’t read “12-07-2019,” and 5) Field B8 is marked “VE” but the V Zone design certifications aren’t attached.
The V Zone certificate certifies that “buildings built in V Zones are anchored to resist wind and water loads acting simultaneously… A registered professional engineer or architect must certify that the design and planned methods of construction meet NFIP requirements. The community must maintain a copy of this certification in the permit file for all structures built or substantially improved in the V Zone.”
Living in the Lowcountry comes with plenty of perks, but flood risk isn’t one of them. It’s important our homes and businesses are built according to regulation, to help mitigate the potential damage caused by flooding. If you’re interested in learning more about flood zones and flood-based architectural regulation, reach out to us! For more information on architectural design and building, keep up-to-date with the Architecture Plus blog. If you’re ready to sit down with an experienced team of designers and hash out the elements of your next project, reach out to us! We’re eager to hear from you. Until next time, thank you for reading!