V-zone

Laying Concrete in V-Zones

to minimize damage and ensure safety

V-zone

Laying Concrete in V-Zones

During a hurricane, Mother Nature is a force to be reckoned with.  The intense precipitation, flooding, and high winds strip materials from buildings, including siding, roof shingles, doors, and windows.  These airborne debris are a major contributor to home damage and human injury.  Therefore, when building on the coast, it’s imperative that your home is compliant with V-zone building codes.  One building material to be very careful with is concrete.  

V-zone
Large pieces of broken concrete can damage buildings and harm people. Image by Mark Wolfe, courtesy of FEMA

Forceful waters and high velocity winds can cause concrete slabs to hydroplane, flip, or break into large chunks that could damage buildings and injure, even kill, people.  As a result, building codes require such slabs be of frangible concrete.  This means they are designed to break into smaller pieces which will sink rather than travel.  So when constructing driveways, pool decks, and patios, it’s important your contractor follows these guidelines:

  • No reinforcement should be used
  • Slabs should not be thicker than four inches
  • Slabs must remain structurally independent of the building
  • Control joints must be spaced at 4-foot squares to encourage even breaking

When laying cement in V-zone areas, proper control joint spacing and depth are essential.  According to the Portland Cement Association, placing control joints in the concrete surface at strategic locations creates weakened planes allowing the concrete to crack evenly.  Spacing the control joints at 4-foot squares ensures the concrete will break into smaller pieces which will cause less damage during hurricanes.

Control joints may be tooled into the concrete surface at the time of placement or they may be sawed into the hardened concrete.  Regardless, control joints should be cut to a depth of ¼ the slab thickness.

V-zone
Control joint. Image courtesy of Portland Cement Association.

Not only is this control joint approach safer, it also produces a more aesthetically pleasing appearance since the crack forms below the finished concrete surface. This method can reduce the amount of hairline cracks on the surface of the cement.

So, when building your vacation home or remodeling to add a backyard oasis, make sure you only work with licensed contractors who are familiar with V-zone construction and the importance of cement control joints.  If you’d like to learn more about concrete, check out our post about reducing surface cracking.


Blog by Jessica T. Smith for the Coastal Cottage Company

One thought on “Laying Concrete in V-Zones”

  1. I did not know that on the east coast it is so important to have a v-zone. I now know that a v-zone is where there is an induced crack so that if there is a natural disaster the concrete does not structurally damage anything around it. Like you said, this style of concrete is not only safer but also more appealing to the eye. I will keep that in mind when looking for a concrete contractor to pave my back yard.

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