Paver Q&A

 For our focus on patios and walkways, Landscape and Irrigation asked Ted Corvey, paver business director at Pine Hall Brick, a Winston-Salem, N.C. manufacturer of clay brick pavers, about paver selection and installation.

LI: What are the benefits of clay pavers?

Corvey: Clay pavers are being re-discovered as a premium pavement material that offers permanent color, long-term life and a variety of styles. 200-year-old clay pavers still in service are all the proof needed to demonstrate that clay pavers can stand the test of time. Modern pavers are produced to meet the stringent standards of ASTM C902 & C1272. Most clay pavers feature compressive strengths in excess of 10,000 psi, cold water absorptions of less than 8 percent, and can handle harsh freeze-thaw environments where the use of de-icing salts are common.

LI: What should landscape professionals keep in mind regarding color and size of the paver?

Corvey: Kiln firing at 2,000 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 full range or blends. Other clays such as 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’t fade or change color over time.

Sizing can be an issue in establishing proper joint width and straight lines. Clay pavers shrink about 10 percent during the firing process. 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.

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 basket weave 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.

LI: What advice would you have for professionals when it comes to incorporating an intricate pattern?

Corvey: Patterns can help define or change the scale of space. In small areas, breaking up the pavement into smaller sections of pavement with different patterns tends to enlarge the area in the mind’s eye. Pattern changes can be used to create emphasis by leading the eye to a focal point such as a fountain or piece of sculpture.

Functional considerations include minimizing cutting. This is not as much a concern on larger jobs, but this can be a factor on smaller jobs where cost to the client is important. In this case, basket weave is ideal in that the pavement can use full pavers throughout given a square or rectangular shape. Using running bond or 90-degree herringbone in square areas requires only half cuts, which can be achieved by using simpler equipment such as a brick splitter or hammer and chisel.

Let go of the idea that every pavement has to be one pattern with a border band. There will be a learning curve to become efficient with new laying patterns, but once you get the hang of it, you have the opportunity to promote your skills. The best single source of leads for a paving installer is generally word of mouth.

LI: What are the benefits of permeable pavers and what special considerations need to be factored into the use of permeable pavers?

Corvey: The benefits are recharging the water table, reducing run-off, reducing storm water discharge into streams and rivers, and reducing thermal pollution. The biggest thing I see at this point is lack of knowledge as we all learn daily about this emerging trend. If you don’t use open-graded aggregates, the system won’t perform. The biggest misconception is that void area is key to infiltrating storm water; no, it’s the open graded aggregates — by using them, void areas can actually be reduced so that the opening are less than 1/2 inch to meet ADA regulations. The second biggest misconception is that permeable pavement systems clog and become ineffective, requiring maintenance. All storm water capture systems will clog over time and require maintenance. Studies show that even over time permeable systems will retain as much as 20 percent of their infiltration capability without maintenance. But maintenance is not that difficult, because most debris orients at the voids and remains on the surface and it can be brushed loose and vacuumed or swept off.

LI: How much training, or what type of training, should industry professionals pursue to become relatively proficient in paver installation?

Corvey: Hardscapes are hot because outdoor rooms are popular. They extend the usable square footage of the home. Outdoor fireplaces and kitchens/grills are adding to the momentum growth. Segmental paving isn’t hard to learn and it can be a nice add-on service for landscapers to boost revenue and profit. Having said that, there are some common mistakes. I said it wasn’t hard to learn, and I believe that leads some to assume that all you have to do is throw down a little sand and pavers. Also, contractors make the mistake of pricing jobs by the square foot versus estimating the job costs and allowing for contingencies. But all jobs are different. How big is it? How much cutting is there? Do I have access to the pavement site? How do I move the materials there? Where are the utilities? What if the customer chooses a more expensive paver and I’ve already given them a price? Should I factor in my overhead in my pricing (you bet you should)? Fortunately, there is good training available. The School for Advanced Segmental Training is excellent [visit] as are many of the ICPI [Interlocking Concrete Pavement Institute] programs. Contractors can also get training at Hardscape North America to be held in October 2010 in Louisville, Ky. Many training classes are available along with demonstrations, outdoor equipment exhibits, and, of course, the expo floor of suppliers to the industry.

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