Landscape Architect Articles

The Joy of Clay Pavers03-01-03 | News

The Joy of Clay Pavers

By Ted Corvey

A residential home in Wisconsin-Salem, North Carolina, displays a classic use for clay pavers reminiscent of Joy Street in Boston?EUR??,,????'???s Beacon Hill.

Strolling up Joy Street in Boston?EUR??,,????'???s Beacon Hill, you can take the same walk that Paul Revere may have taken in 1802 as he supervised the copper cladding on the new State House dome. ?EUR??,,????'??The same walk??EUR??,,????'?? you ask. The very same walk. That?EUR??,,????'???s because Beacon Hill preserves its heritage by maintaining the brick row houses, gas lamps and clay paver sidewalks put in place 200 years ago. Behind the times? Maybe. A testament to durability? Absolutely.

Despite a rich heritage and a track record of longevity, clay pavers were slowly forgotten over the centuries since Revere?EUR??,,????'???s time. Today, they are being re-discovered as a premium pavement material offering permanent color, long-term life and a variety of styles. But, as with anything forgotten over time, knowledge decreased and misconceptions developed about what once was the only manufactured paver you could buy.

Sturdy Enough?

200-year-old clay pavers still in service are all the proof needed to demonstrate that clay pavers can stand the test of time. True, you may see an older paver that has failed. Usually that?EUR??,,????'???s because the paver was actually not a paver at all but a ?EUR??,,????'??solid?EUR??,,????'?? face brick not fired to the proper temperature.

A private residence, also located in Winston-Salem, shows how clay pavers will interlock effectively in sand-set segmental pavement. The above hardscape is designed for both pedestrian and vehicular use.

Today?EUR??,,????'???s clay pavers are made to stand up to everything that man and Mother Nature can hand out. Modern pavers are produced to meet the stringent standards of ASTM C902 & C1272. Most clay pavers feature compressive strengths in excess of 10,000psi, cold water absorptions of less than 8% and can handle the harshest North American freeze-thaw environments where the use of de-icing salts are common.

The Interlock Myth

To their credit, the concrete paver industry has done an excellent job at promoting flexible base paving and associating their product with the word ?EUR??,,????'??interlocking.?EUR??,,????'?? This association creates a myth that shape and material are critical to creating interlock. In reality, clay pavers will interlock effectively in any sand-set segmental pavement, pedestrian or vehicular (properly designed, of course).

Clay pavers in this park are used solely for pedestrian use.

Research conducted by J.M. Clifford concludes that proper joint width (1/8") is important to establishing optimum interlock. Clay pavers featuring spacer nibs address proper joint width in that the nib establishes proper spacing. However, as a general rule, molded clay pavers and square edge clay pavers do not feature nibs/spacers. Hand tight placement may eliminate joints all together, compromising interlock and promoting chippage. With non-nibbed units, installers need to employ the click and drop method of placement or other spacing methods in order to create a proper joint.

Sizing can also be an issue in establishing proper joint width and straight lines. Clay pavers shrink about 10% during the firing process where temperatures reach in excess of 2000 degrees. Depending on the type of kiln and raw material, size variation can occur and as a result, the clay paver standard calls out three different standards for permissible variation (PX, PS, PA) with PX providing the most consistent sizing.

Another walkway captures the classic style of Beacon Hill. The walk runs the length of a residential neighborhood.

For the installer, a dimensional inspection of the pavers prior to installation is important. The laying module (with string or chalk lines) must be established based on the largest pavers at the job. In this way, patterns such as herringbone and basketweave can be laid without major adjustment of pavers on the ground. In some cases, a simple switch to running bond can solve a size problem and create a colonial look. In other cases, a switch to a more consistent paver may be the answer. Several manufacturers, including Pine Hall Brick, are employing specialized production and firing methods to minimize size variation to plus or minus 1/8" (PX) or better.

Natural Color, Natural Product

Kiln firing at 2000 degrees fuses clay particles together in a vitrified bond to produce permanent color and long life.

Since natural deposits of clay differ slightly from region to region, similar colors will vary from manufacturer to manufacturer offering a wide range of choice. The most common color is red, and that color can be altered through a firing technique called flashing. Flashing changes some red pavers to browns and charcoals to form what is known as ?EUR??,,????'??full range?EUR??,,????'?? or blends. Other clays like kaolin and fire clay can be mixed with red clay (or fired alone) to produce lighter colors like pink and buff. Whatever the color, the vitrification process means that clay pavers don?EUR??,,????'???t fade or change color over time.

Traditional and colored pavers are used to beautify this residence.

Although most clay pavers are rectangular in shape, some manufacturers are offering dog bone shapes and octagons. Pine Hall Brick recently introduced an 8 X 8 paver with Accent one corner cut off to offer a tile-like appearance.

The joy of clay pavers is found in their natural beauty and heritage. By tossing aside the misconceptions, you can discover an opportunity to expand your business by offering genuine clay pavers.

About the author:

Ted Corvey is the Paver Business Director and Marketing Director for Pine Hall Brick in Winston Salem, North Carolina. In addition, He serves as Chairman of the Brick Industry Association’s Paving Committee. He can be reached at info@pinehallbrick.com.