This is the 3rd of a series on important things to consider if you are thinking about buying raw acreage and building a home in the Blue Ridge Mountains.
Part 1 gave you a quick primer on how to us the county GIS (Geographic Information System) to analyze the property and decide whether it might be worth a closer look.
Part 2 talked about accessibility issues.
In Part 3, we’ll cover whether a piece of land can successfully support a home.
Evaluating Slopes
Buildable land comes at a premium in the mountains. According to ACM Design in Fletcher, as few 1/5th of parcels for sale in the Asheville Region are described as level.
The GIS Map shown above depicts Buncombe County with the Steep Slope and Protected Ridge overlay turned on.
Buncombe County’s Steep Slope Ordinance requires that structures above 2,500 feet be constructed on soils with a slope no greater than 35%. The Protected Ridge Overlay District requires that structures above 3,000 feet be constructed on soils with a slope no greater than 35% and be at least 500 feet away from a ridgeline.
Why is this ordinance in place? Anyone who lived through hurricane Helene can tell you: in the mountains, landslides are a risk. Here is more information on landslide management in Buncombe County.
Go to the GIS and search for the property you are considering. Turn on the Steep Slope layer (not all county maps make this available.)
If there is no steep slope layer, turn on the elevation layer and set it to view 20’ increments. Each line will show a 20’ change in elevation. If the resulting map looks like either of the illustrations shown above it’s important to take a close look at whether it is buildable.
Zoom in. Where the lines diverge, you’ll see that is where the buildings are. As the lines move apart, the land flattens out; where they converge it get steeper. When evaluating a parcel. Observe if and where the lines move apart. That will be your best build site.
If you decide to build where the land is on a steep slope, a geotechnical analysis must be done as well as a second analysis after the project is complete. My advice: if in doubt, have this done as part of your due diligence when considering a property.
Building on Slopes
Why are properties with steep slopes so much cheaper? Building on them is much more expensive. If you want to build up at the top of that parcel to maximize the view a road needs to be cut out. If the slope is steep, the road will need to have switchbacks, extending the length of the road and increasing the cost. Building a structure on a steep slope also gets expensive. The foundation will need to be engineered to accommodate the terrain which might add $100K or more to the budget. More materials are required and a lot of dirt (and rock) need to be moved around. Here is a link to a document illustrating the complications of building on a slope
Slopes and Septic Systems
Most areas in Western NC that have steep slopes are beyond the reach of municipal water and sewage systems. This means a septic system will have to be installed.
Where is the best build site on the property? Is it at the top or at the bottom near the existing road (if there is one). If it’s near the bottom you will have less road to clear to access the build site, but this will create more expense when installing septic. Water always flows downhill and ideally your septic system should be gravity fed, below the house. If locating it above is necessary, waste will need to be pumped up to the leach field which will require additional engineering and installation expense. Here is more information on septic systems. Your well will also need to be located above the leach field, requiring a long run to the house.
In the next installment of Buying Mountain Land, we’ll talk about further restrictions you might encounter, the process of clearing and homesteading. Stay tuned.
In the meantime, if you have any questions about purchasing land or anything real estate in Western North Carolina, please give me a call.
