With Flooding On The Rise: How To Elevate Your Historic Home

Home foundation

Flooding is a topic high on the agenda of many Charleston SC residents. If you are planning a significant renovation or remodel then elevating your home really is a topic worth investigating, primarily if the cost can be distributed or “amortized ” over an extended period within the initial construction loan or mortgage. We know this firsthand, as this is expertise that we are well versed in, and the task of elevating a home is the exact route we have taken with our latest six historic renovations. Here is some insight to the “why and how ” of these projects.

So firstly, what are these projects? Each one is a historic home located downtown on the Charleston peninsula with an original build date between 1840 and 1890. One is on St Philip Street in the Elliotborough neighborhood, and the other five are located on Nassau and Hanover Streets on the East Side. A further two will follow, also on Nassau St., one of which we are doing the work for our own portfolio and one for Star Gospel Mission. In each, the renovation is a “strip to the bones” variety for a derelict or very dilapidated property. In two instances, we are also correcting a distinct lean of the home, probably resulting from the earthquake of 1886 or a subsiding chimney stack, the result of being footed directly on dirt and as been slowly sinking since -or in some cases suffering from both of these! There was a time in the very recent past when the City of Charleston Board of Architectural Review (BAR) discouraged elevating buildings, preferring instead to preserve the historic street frontage. This was the case with a current project we completed at 63 Radcliffe St. However, times are changing, and after several consecutive years of visits by a hurricane or two, a tropical storm and persistent “King Tide ” flooding, the City of Charleston has responded to considerable public and political input with a more conciliatory stance, often agreeing to request to elevate a home provided that the additional construction remains in sympathy with its surroundings.

So here we are, in possession of a portfolio of buildings in a miserable state of disrepair, with construction financing from Pinnacle Bank in place and we are off to the races. The first steps for us are to focus on elevating these older homes because the benefits are obvious and favorable for long-term ownership. Here’s what you can gain from elevating the foundation:

• Lower flood insurance costs (helping considerably to pay for the additional financing)

• Less flood risk – no one likes the mess that comes with a home repeatedly filled with water, mud and in some cases, sewage

• A level and upright home – “old Charleston charm” only goes so far when you actually live in the house

• New, substantial footings that meet Code and adequately connect the building to the ground. A better foundation and a bit of added fortitude against the the hurricanes that blow in this part of the country

LIFTING THE FOUNDATION

So how does this all work? You need contractors who understand the task at hand, both regarding the actual lift process itself, and that includes  the “pre-lift ” demolition, the “shoring ” and the “post-lift ” reconstruction. That’s a lot of work to cover, but it’s by no means out of the ordinary for the contractors who work daily in this city. You also need to understand your soil conditions. On Nassau Street, we have ancient sand and dirt mixtures that are a suitable substrate for load bearing. On St Philip, we have a softer substrate necessitating the addition of “auger footings, ” driven to 25 feet depth then continuous concrete footers constructed on top of these. I know of at least one elevation near Colonial Lake (on Rutledge Avenue) undertaken by a friend that needed to have piles installed to 80 feet depth before they hit load bearing marl layer. The “pluff mud “so commonly found in the marshes and creeks of the Charleston lowcountry does not make for a stable foundation!

Elevating-your-charleston-sc-home-lift-foundation

Next, the building is stripped. This can be down to the studs – or to a lesser extent – but in either case must be sufficient to allow the structure to be reinforced or otherwise secured. A older, balloon-framed house with considerable termite damage cannot itself be trusted to stay upright.

So the building is demolished internally. We remove window sashes or risk them breaking as the structure becomes once more square and upright. Shoring is in place, plus whatever reinforcement necessary to provide for a secure point for the lifting jacks and support beams. Chimneys can be a real problem, as they are very heavy and the BAR like to retain them if at all possible. The old lime mortar of brick chimneys is basically sand keeping the bricks apart but with no real integrity of adherence. They will need elevating also, though a frequent compromise is to remove them and then rebuild the chimney only above the roof line. If the exterior has been previously removed, then the whole chimney stack can be demolished internally making for much more space in an often small cramped home.

Elevating-your-charleston-sc-home

Next, the home will need to be lifted 2 feet or so higher than its final elevation. This is to allow for access to footings and support block work. The lift points need to be carefully planned so as not to interfere with the installation of new footings once it’s raised. Usually, this means lifting either internally or external to the foundation footprint through the whole structure and supporting wall plate or rim beam. Old footings are typically “grubbed out ” and replaced with steel rebar and new continuous footings. Footings will also have metal straps leading from the rebar through to the actual framing of the house ensuring all are tied together.

Foundations are inspected, poured, inspected again. Block work is set to support the home at its new final elevation, and when all of this is in place, the old house is gently lowered and secured. The process is slow, but it’s also quite remarkable the difference you experience once all the windows and doors return to level and square.

Then the process of reconstruction begins in earnest. And in the end? You will gain a historic home but with the performance and maintenance requirements of a brand new one. A home secured against torrential rain storms and free of flood risk short of something so catastrophic it would be akin to total Armageddon. It’s a scary process in some respects, but also one that’s now thankfully happening with increasing frequency all over this beautiful historic city of ours.

One final thought, your home is now free of flood risk, but your yard is not. Be careful where you park your vehicle when the wind blows up a tropical storm, or the tide rises on a full moon!