Question of the Day - 22 November 2005

We called the City of Las Vegas Building & Safety Department to get the skinny on this. Interestingly, they didn’t have a definitive answer. They confirmed that there are certainly no impediments in the form of planning codes or building regulations that prohibit basements, but they did offer some likely explanations as to why they're unusual in Las Vegas:

• One theory they suggested was the fact that in parts of the country where the ground freezes, building foundations must be dug down below the frost line. Once you’ve dug that far down, you might as well keep digging awhile and create a useful basement level. In Las Vegas, however, it doesn’t get cold enough for the ground to freeze in the winter, so there’s no structural imperative for costly excavations.

• The issue of flash-flooding could also come into play. Although this is a very dry city for much of the year, dramatic thunderstorms do occur, particularly between July and September, when moist unstable air coming in from the Gulf of Mexico is rapidly forced upward by hot air currents over the desert. Because of the steep mountainous terrain surrounding the valley and the fact that the ground is so dry for much of the year, there’s a problem with surface runoff leading to flash floods. If your home is on the floodplain, as many are, that’s another good reason not to have a basement.

• The final practical consideration is the issue of caliche, a phenomenon that occurs in desert and semi-arid areas when groundwater that’s rich in lime (calcium carbonate) rises up through the soil via capillary action and evaporates, depositing an impermeable layer beneath the surface that’s as tough as concrete. It’s possible to have a soil test performed prior to digging your foundations, which is advisable if you're considering building a basement, because if caliche is discovered, you could be looking at a sizable bill if you want to dig down through it.

• The fourth, and perhaps most widely applicable answer to your question, is not so much a practical consideration as simply an issue of custom. Although our Building Dept. source confirmed that he personally knows of several houses in the area that do have basements, it’s just not the established style in Las Vegas, where homes have traditionally been based more on the single- or two-story "ranch" model.